t'f . Q c::;..ktz.d Lt1¢. P~ ,4ctc-..:>k'*'?e.Jl Re.ce:~ Ievols.library.manoa.hawaii.edu/bitstream/handle/10524/33706/1992... · c/o ARCO Oil & Gas 4550 California Avenue Bakersfield,

R- A- PATTERSON & ASSOCIATES

Manabu Tagamori-DOWALD a Date: November 9, ~992

SUBJECT: BOP

...._[,) . Q_ . ~ c::;..ktz.d" Lt1¢. "''t'f P~ ,4ctc-..:>k'*'?e.Jl Re.ce:~ \,_, Manual draft - Suggested reviewers REVISED I

A REVISED listing of suggested reviewers for the draft BOP Manual, is as follows:

Bill Rickard

Paul Stroud

y-Louis E. Capuano, Jr./

Allan Frazier

Jerry Hamblin

v-<>ete Wygle ,.....----

_.-Bi 11 Tepl ow~

...-- Bi 11 Craddi ckv-

Gary Hoggatt

Dunn, James c.

~ene Anderson~

Robert Wagner

1

ThermaSource, Inc. P. 0. Box 1236 Santa Rosa, CA 95402

0

Tecton GeoV(gic P.O. Box 1349 Healdsburg CA 95448

UNOCAL Geothermal Division P. 0. Box 6854 Santa Rosa, CA 95406

California DOG 1000 South Hill Rd. Ventura CA 93003-4458

1518 Excelsior Oakland CA 94602

Barnwell Industries 2828 Paa St. Ste 2085 Honolulu HI 96818

TRUE Geothermal Drilling P. 0. Box 2360 Casper WY 82602

Sandia National Laboratories P. 0. Box 5800, Division 6252 Albuquerque NM 87185

Nabors Loffland Drilling Co. P. 0. Box 418 Bakersfield CA 93302

PARKER Drilling Co. 8 East Third st. Tulsa OK 74103

f

~ Richard Thomas

'~.t. ~""'.......,(~ 17e-k wy,le ~ V'"' "' f'""" ~

Bowen E. Roberts

Geothermal Officer California DOG 801 K Street - MS 22 Sacramento CA 95814-3530

ARCO Oil & Gas 4550 California Ave. Bakersfield CA 93309

We have not included any Hawaii State or County officials, as many of these will likely see the draft anyway. A possible draft cover letter is attached.

If there are any questions about the above list, or if we can provide more information on possible reviewers, please call.

2

• R_ A- PATTERSON & ASSOCIATES

Date: November 9, 1992

TO: Manabu Tagamori-DOWALD

SUBJECT: BOP Manual draft - Suggested reviewers REVISED

A REVISED listing of suggested reviewers for the draft BOP Manual, is as follows:

Bill Rickard ('""' ~ti/. . .. _.( ). ( ,.- ~' ") ·/l < ~-.,: ~ l

Stroud · Paul

Louis E. Capuano, Jr.

Allan Frazier

Jerry Hamblin

Pete Wygle

Bill Tepl ow

Bill Craddick

Gary Hoggatt

Dunn, James C.

Gene Anderson

Robert Wagner

1

ThermaSource, Inc. P. o. Box 1236 Santa Rosa, CA 95402

" Tecton Geol-r'gic P.O. Box 1349 Healdsburg CA 95448

UNOCAL Geothermal Division P. 0. Box 6854 Santa Rosa, CA 95406

California DOG 1000 South Hill Rd. Ventura CA 93003-4458

1518 Excelsior Oakland CA 94602

Barnwell Industries 2828 Paa St. Ste 2085 Honolulu HI 96818

TRUE Geothermal Drilling P. 0. Box 2360 Casper WY 82602

Sandia National Laboratories P. 0. Box 5800, Division 6252 Albuquerque NM 87185

Nabors Loffland Drilling Co. P. 0. Box 418 Bakersfield CA 93302

PARKER Drilling Co. 8 East Third St. Tulsa OK 74103

Richard Thomas

Bowen E. Roberts

Geothermal Officer California DOG 801 K Street - MS 22 Sacramento CA 95814-3530

ARCO Oil & Gas 4550 California Ave. Bakersfield CA 93309

We have not included any Hawaii State or County officials, as many of these will likely see the draft anyway. A possible draft cover letter is attached.

If there are any questions about the above list, or if we can provide more information on possible reviewers, please call.

2

-JO~IN WAIHEE

GOVERNOR OF HAWAII

~F1 ~

Dear ~F2 ~:

~~}-~~-~~--~-;~~~~---.

~~-~) STATE OF HAWAII

DEPARTMENT OF LAND AND NATURAL RESOURCES DIVISION OF WATER AND LAND DEVELOPMENT

P. 0 fiOX 373

HONOLULU, IIAWAII 961:109

DEC -4 1992

,'-.. ,_/ {_ 0-r--·--l ' .

WILLIAM W PATY, CHAIRPERSON

BOAR[} OF LANO ANO NATURAl RESOURCES

[)EPUII~S

JOHN P. KEPPELF=R, II DONA L. HANAIKE

AQUACULTURE DEVELOPMENT PROGRAM

AQUATIC RESOURCES

CONSERVATION AND ENVIRONMENTAl AFrAIRS

!"":ONSERVATION AND RESOIJRCfS ENFORCEMErH

C'ONVErMKES fORESTRY AND WILDLirf HISIOfliC f'RESERvAriON

f'HO(;PM,1

LAND MIIN.~r,EMfNI .5\AI( P/lni'.S

1'1/ITER liND L/ltJD D~','f~OPMft-H

As a result of recommendations made in the "Independent Technical Investigation of the Puna Geothermal Venture Unplanned Steam Release", of June 12-13, 1991, the Department of Land and Natural Resources has contracted the preparation of the Hawaii Geothermal Blowout Prevention Manual.

This document is intended to provide clear guidance that both regulatory agencies and geothermal development organizations can use for plans and procedures regarding blowout prevention in their Hawaii drilling activities. The enclosed draft of the Manual is designed to improve operational and safety procedures for ALL geothermal drilling activities in the State.

A draft copy of this Manual is enclosed for your information, review, and comment; we would appreciate your review and comments on the draft so that the final Manual will reflect the exp<';riences and thoughts of the industry and other regulatory agencies.

In order to maintain our production schedule, we would appreciate your forwarding comments to us by December 28, 1992. Your comments, and others that we may receive, will be considered in the preparation of the final document.

Your help to the State of Hawaii in this review is appreciated; we hope to manage the Hawaii geothermal resources so that the best possible development practices are followed at all times.

JF:lc En c.

me rely, /------~------._

MA BU TAGOMO {I er-Chief Eng· eer

Mr. Bill Rlcitard cjo Resource Group P.O. Box 1483 Healdsburg, California 95448

Mr. Allan Frazier cjo Tecton Geologic P.O. Box 1349 Healdsburg, California 95448

Mr. Bill Teplow 1518 Excelsior Oakland, California 94602

Mr. James C. Dunn cjo Sandia National Laboratories P .0. Box 5800, Division 6252 Albuquerque, New Mexico 87185

Mr. Richard Thomas Geothermal Officer California DOG 801 K Street - MS 22 Sacramento, California 95814·3530

Mr. Paul Stroud c/o Resource Group P.O. Box 1483 Healdsburg, California 95448

Mr. Jerry Hamblin c/o UNOCAL Geothermal Division P.O. Box 6854 Santa Rosa, California 95406

Mr. Bill Craddick c/o Barnewll Industries 2828 Paa Street, Suite 2085 Honolulu, Hawaii 96818

Mr. Gene Anderson c/o Nabors Loffland Drilling Co. P.O. Box 418 Bakersfield, California 93302

Mr. Bowen E. Roberts c/o ARCO Oil & Gas 4550 California Avenue Bakersfield, California 93309

Mr. Louis E. Capuano, Jr. c/o ThermaSource, Inc. P .0. Box 1236 Santa Rosa, California 95402

Mr. Pete Wygle c/o California DOG 1000 South Hill Road Ventura, California 93003-4458

Mr. Gary Hoggatt c/o TRUE Geothermal Drilling P.O. Box 2360 Casper, Wyoming 82602

Mr. Robert Wagner c/o PARKER Drilling Co. 8 East Third Street Tulsa, Oklahoma 74103

.JOHN WAIHEE

GOVERNOR OF HAWAII

STATE OF HAWAII DEPARTMENT OF LAND AND NATURAL RESOURCES

DIVISION OF WATER AND LAND DEVELOPMENT

Mr. Bill Rickard c/p Resource Group P.O. Box 1483 Healdsburg, California 95448

Dear Mr. Rickard:

P. 0. BOX 373

HONOLULU, HAWAII 96809

DEC -4 1992

WILLIAM W. PATY, CHAIRPERSON

90ARO OF LAND AND NATURAl flESOURCES

DEPUTIES

JOHN P. KEPPELER, II DONA l. HANAIKE


AQUATIC RESOURCES CONSERVATION AND

ENVIRONMENTAL AFFAIRS CONSERVATION AND

RESOURCES ENFORCEMENT CONVEYANCES FORESTRY AND WILDLIFE

HISTORIC PRESEAVATION PROGRAM

LAND MANAGEMENT

STATE PARKS

WATER AND LAND DEVELOPMENT

A5 a result of recommendations made in the "Independent Technical Investigation of the Puna Geothermal Venture Unplanned Steam Release", of June 12-13, 1991, the Department of Land and Natural Resources has contracted the preparation of the Hawaii Geothermal Blowout Prevention Manual.


A draft copy of this Manual is enclosed for your information, review, and comment; we would appreciate your review and comments on the draft so that the frnal Manual will reflect the experiences and thoughts of the industry and other regulatory agencies.

In order to maintain our production schedule, we would appreciate your forwarding comments to us by December 28, 1992. Your comments, and others that we may receive, will be considered in the preparation of the frnal document.


JF:lc En c.

~[c;;;?_ M UTA~! Man er-Chi~~~~~!eer

JOHN WAIHEE

GOVERNOR OF HAWAU



Mr. Paul Stroud c/o Resource Group P.O. Box 1483 Healdsburg, California 95448

Dear Mr. Stroud:

P. 0. BOX 373


DEC -4 1992

WILLIAM W. f>ATY, CHAIRPERSON

90ARO OF LAND AND NATURAL RESOURCES

DEPUTIES

JOHN P. KEPPELER. II DONA L. HANAIKE

AQUACULTURE DEVELOPMENT

PROGRAM AQUATIC RESOURCES CONSERVATION AND


RESOURCES ENFORCEMENT

CONVEYANCES FORESTRY AND WILDLIFE HISTORIC PRESERVATION

PROGRAM

LAND MANAGEMENT STATE PARKS WATER AND LAND DEVELOPMENT

As a result of recommendations made in the "Independent Technical Investigation of the Puna Geothermal Venture Unplanned Stearn Release", of June 12-13, 1991, the Department of Land and Natural Resources has contracted the preparation of the Hawaii Geothermal Blowout Prevention Manual.


A draft copy of this Manual is enclosed for your information, review, and comment; we would appreciate your review and comments on the draft so that the fmal Manual will reflect the experiences and thoughts of the industry and other regulatory agencies.



JF:lc En c.

RI er -Chief Engineer

JOHN WAIHEE

GOVERNOR OF liAWAII

STATE OF HAWAII


Mr. Louis E. Capuano, Jr. c/o ThermaSource, Inc. P.O. Box 1236 Santa Rosa, California 95402

Dear Mr. Capuano:

P. 0. BOX 373

HONOLULU, HAWAll 96809

DEC -4 1992

WILLIAM W. PATY. CHAIRPERSON

BOAAO OF LANO ANO NATURAl RESOURCES

DEPUTIES

JOHN P. KEPPELER, Jl DONA L. HANAIKE

AQUACULTURE DEVElOPMENT PROGRAM

AQUATIC RESOURCES

CONSERVATION AND ENVIRONMENTAl AFFAIRS

CONSERVATION AND

RESOURCES ENFORCEMENT CONVEYANCES FORESTRY AND WILDLIFE HISTORIC PRESERVATION

PROGRAM

LAND MANAGEMENT STATE PARKS




A draft copy of this Manual is enclosed for your information, review, and comment; we would appreciate your review and comments on the draft so that the final Manual will reflect the experiences and thoughts of the industry and other regulatory agencies.



JF:lc En c.

--------------,~

JOHN WAIHEE

GOVERNOR OF HAWAtt

STATE OF HAWAII


Mr. Allan Frazier c! o Tecton Geologic P.O. Box 1349 Healdsburg, California 95448

Dear Mr. Frazier:

P. 0. BOX 373

HONOLULU. HAWAII 96809

DEC - 4 1992


BOARO OF LAND AND NATURAL RESOURCES

DEPUTIES

JOHN P. KEPPELER, II

DONA L. HANAIKE


PROGRAM AQUATIC RESOURCES

CONSERVATION AND



CONVEYANCES FORESTRY AND WILDLIFE

HISTORIC PRESERVATION PROGRAM

LAND MANAGEMENT

STATE PARKS WATER AND LAND DEVELOPMENT






JF:lc En c.

JOHN WAIHEE

GOVERNOR OF MAWAII

STATE OF HAWAII

DEPARTMENT OF LAND AND NATURAL RESOURCES


Mr. Jerry Hamblin c/9 UNOCAL Geothermal Division P.O. Box 6854 Santa Rosa, California 95406

Dear Mr. Hamblin:

P. 0. BOX 373


DEC -4 1992


BOARD OF LANO AND NATURAL RESOURCES

DEPUTIES

JOHN P. KEPPELER, II DONA L. HANAIKE


AQUATIC RESOURCES

CONSERVATION AND





LAND MANAGEMENT

STATE PARKS WATER AND LAND DEVELOPMENT




In order to maintain our production schedule, we would appreciate your forwarding comments to us by December 28, 1992. Your comments, and others that we may receive, will be considered in the preparation of the fmal document.


JF:lc En c.

JOHN WAIHEE

GOVERNOR OF HAWAII

STATE OF HAWAII



Mr. Pete Wygle c/o California DOG 1000 South Hill Road Ventura, California 93003-4458

Dear Mr. Wygle:

P. 0. BOX 373


DEC - 4 1992


BOARD Of LAND AND NATURAL RESOURCES

DEPUTIES



AQUATIC RESOURCES

CONSERVATION AND ENVIRONMENTAL AFFAIRS

CONSERVATION AND RESOURCES ENFORCEMENT










JF:lc En c.

JOHN WAIHEE

GOVEflNOR OF HAWAII

Mr. Bill Teplow 1518 Excelsior



P. 0. BOX 373


DEC - 4 1992

Oakland, California 94602

Dear Mr. Teplow:


BOARD OF LAND AND NATURAL RESOURCES

DEPUTIES



AQUATIC RESOURCES












JF:lc En c.

erely,

RI er-Chief Engineer

JOHN WAIHEE

GOVERNOR OF HAWAII

STATE OF HAWAII

-,



Mr. Bill Craddick c/o Bamewll Industries 2828 Paa Street, Suite 2085 Honolulu, Hawaii 96818

Dear Mr. Craddick:

P. 0. BOX 373


DEC - 4 1992

WilliAM W. PATY, CHAIRPERSON


DEPUTIES



PROGRAM AQUATIC RESOURCES CONSERVATION AND



PROGRAM


As a result of reconunendations made in the "Independent Technical Investigation of the Puna Geothermal Venture Unplanned Steam Release", of June 12-13, 1991, the Department of Land and Natural Resources has contracted the preparation of the Hawaii Geothermal Blowout Prevention Manual.

This document is intended to provide dear guidance that both regulatory agencies and geothermal development organizations can use for plans and procedures regarding blowout prevention in their Hawaii drilling activities. The enclosed draft of the Manual is designed to improve operational and safety procedures for ALL geothermal drilling activities in the State.

A draft copy of this Manual is enclosed for your information, review, and conunent; we would appreciate your review and conunents on the draft so that the final Manual will reflect the experiences and thoughts of the industry and other regulatory agencies.



JF:lc En c.

erely,

r -Chief Engineer

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Gary Hoggatt c/o TRUE Geothermal Drilling P.O. Box 2360 Casper, Wyoming 82602

Dear Mr. Hoggatt:

P. 0. BOX 373


DEC - 4 i992


BOARO OF LA.IIID AIIIO IIIATURAL RESOURCES

DEPUTIES



AQUATIC RESOURCES












JF:Ic Enc.

Mru,noU TAGOMORI r -Chief Engineer

JOHN WA!HEE

GOVERNOR OF HAWA.II



Mr. James C. Dunn c/o Sandia National Laboratories P.O. Box 5800, Division 6252 Albuquerque, New Mexico 87185

Dear Mr. Dunn:

P. 0. BOX 373


DEC - 4 1992

WILUAM W. PATY, CHAIRPERSON

BOARO OF LA.NO A.NO NATURAl RESOURCES

OEPUTIES

JOHN P. KEPPELER. U DONA L. HANAIKE


AQUATIC RESOURCES


CONSERVATION AND



PROGRAM




This document is intended to provide dear guidance that both regulatory agencies and geothermal development organizations can use for plans and procedures regarding blowout prevention in their Hawaii drilling activities. The enclosed draft of the Manual is designed to improve operational and safety procedures for ALL geothermal drilling activities in the State.




JF:lc Enc.

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Gene Anderson c/o Nabors Loffland Drilling Co. P.O. Box 418 Bakersfield, California 93302

Dear Mr. Anderson:

P. 0. BOX 373


DEC - 4 1992


BOARD OF LAND ANO NATURAL RESOURCES

DEPUTIES



AQUATIC RESOURCES




PROGRAM







JF:k En c.

JOHN WAIHEE

GOVER"'IR OF HAWAU



Mr. Robert Wagner c/e PARKER Drilling Co. 8 East Third Street Tulsa, Oklahoma 74103

Dear Mr. Wagner:

P. 0. BOX 373


DEC - 11 1992



DEPUTIES



AQUATIC RESOURCES

CONSERVATION ANO ENVIRONMENTAL AFFAIRS

CONSERVATION AND

RESOURCES ENFORCEMENT CONVEYANCES

FORESTRY AND WILDLIFE HISTORIC PRESERVATION

PROGRAM







JF:lc En c.

RI

JOHN WAIHEE

GOVERNOR OF HAWAII WILLIAM W. PATY, CHAIRPERSON

BOARD OF LAND AND NATURAl RESOURCES

DEPUTIES





AQUATIC RESOURCES

CONSERVATION AND


P. o. eox 373



FORESTRY AND WILDLIFE


LAND MANAGEMENT STATE PARKS DEC - ~ /992 WATER AND LAND DEVELOPMENT

Mr. Richard Thomas Geothermal Officer California DOG 801 K Street - MS 22 Sacramento, California 95814-3530

Dear Mr. Thomas:



'




JF:lc En c.

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Bowen E. Roberts c/o ARCO Oil & Gas 4550 California Avenue Bakersfield, California 93309

Dear Mr. Roberts:

P. 0. BOX 373


DEC - 4 1992



OE?UTIES



AQUATIC RESOURCES


CONSERVATION ANO


FORESTRY ANO WILDLIFE


LAND MANAGEMENT

STATE PARKS







JF:lc En c.

R. •A. PATTERSON& ASSOCI' .. ms_ 1274 Kika Street Aailua, Hawaii 96734-4521 (808) 262-5651 (808) 262-5350 (FAX)

September 20, 1993

Mr. Manabu Tagomori Department of Land & Natural Resources Division of Water and Land Development P. 0. Box 373 Honolulu, HI 96809

Dear Mr. Tagomori;

kECEJVEO

53 S E p 22 A 9 ; I 5

In accordance with, and in partial fulfillment of, our technical services contract, two bound, and one loose, copies of the HAWAII BLOWOUT PREVENTION MANUAL are forwarded.

A diskette containing the files used to produce this document is also enclosed. The document files are in WordPerfect 5.1 format; there are three WP master documents BOPPREFC.MST, BOPCNTNT.MST, AND BOPREVIS.MST. The cover and appendix division sheets were produced in Harvard Graphics format; copies of these files are also included.

We have made the changes and corrections requested in your letter of September 7, 19 3 3. However, we remain concerned that the DLNRdesired wording describing the optional BOP stack configuration, (Section IV, page 17) would create a hazardous situation in the event of another failure of the wing valves (similar to that which occurred at the KS-1 well in October 1982). If the wing valves are below the ram preventer, an important safety back-up would be missing in the event that the small valves fail or need repair; there would be no last resort to preventing a blowout in this area of the stack.

We are anxious to complete the remaining document reviews and delivery before the end of September. In order to do this, we will have to receive comments on the previously submitted draft of the "DRILLING GUIDE," by Friday, September 24th. If it is not possible to provide these comments by that date, we will have to delay corrections and completion of the Manual until November, due to our other commitments. These include attendance at the annual Geothermal Resources Council meeting, where discussions about Hawaii may include these important publications.

The corrections and deliveries can be expedited, but we will need a reasonable time to make the corrections and do the printing and binding when the staff reviews are completed.

enclosures cc: RCUH (letter only) bee: G. Akita, J. Flores

Sincerely,

TO: !NIT:

M. TAGOMORI L. Nanbu G. Akita

__ L. Chang E. Lau A. Monden

1 1~"'1 H. Young _T.Kam

R. LOUI S. Kokubun

__ See Me

=folh ~ ReVIew & Comment

Take Action __ Investigate & Report ..U r7t _ )?lraft Reply "- V' H-, __ /Acknowledge Receipt __ Type Draft __ Type Final

Xerox __ copies File

FOR YOUR:

Approval Signature Information

·; / ': ·,~. ~ i! \l"t: ~·c-/' ~.i~ I

Water Resourcr· 'nternationaL Inc.

Mr. Manabu Tagamori Manager-Chief Engineer Dept. of Land & Natural P.O. Box 373 Honolulu, Hawaii 96809

Resources

Subject: GEOTHERMAL BLOWOUT MANUAL

Dear Mr. Tagamori,

December 17, 1992

I received your Geothermal Blowout Manual. After reading it, I would like to suggest the following to be considered, as I believe these items to be very important.

1. The drilled hole must be surveyed as the hole is being drilled. This is necessary in order to drill an offset well to kill any well that has no capability to be killed from the original hole. You know the ramifications if one well ever blows out and we are not able to plug it because we didn't take all possible precautions.

2. The final cemented liner casing must be checked for damages. This is very important as the casing is subject to a lot of local wear, especially in a direction hole.

3. I think that serious thought should be given to completely enclosing the drill site so that no noise would escape due to drilling, unloading trucks, etc.

Should you have any further questions regarding my suggestions, I would be more than happy to discuss them in detail with you. I can be reached at the following Hilo phone number, 959-3852, during the next two weeks, as our Hilo office will be shut down for the holidays.

Yours truly,

~v)~ ~ W.R. ~ddick J Sr. Vice President

WRC/kw

2828 Paa Street • Suite 2085 • Honolulu. Hawaii 96819 • Telephone (808) 839-7727 • Telecopier (808) 833-5577 • Telex 7238672 WAll HR

Tl1erma5ourre,Nc. GEOTHERMAL CONSULTING SERVICES

83 JAN 8 A B : 22 January 4, 1993

Mr. Manabu Tagamori Division of Water and Land Development Department of Land and Natural Resources State of Hawaii Honolulu, Hawaii 96809

Dear Mr. Tagamori,

We have reviewed a draft of Hawaii Geothermal Blowout Prevention Manual, and offer the following comments:

1. As well data becomes public, DOWALD should maintain a summary of drilling information to be made available to Operators. This would include casing depths, hole sizes, temperature, pressure, and drilling problems encountered. This would aid in well design and hopefully expedite the permitting process.

2. More details of KS-7 and KS-8 should be made public in technical forums such as GRC meetings or seminars. We consider these wells valuable for case history purposes in order to prevent future well control problems and demonstrate unique aspects of drilling in the Kilauea East Rift.

3. Make Blowout Certification mandatory permit issuance. Since human error is a blowouts, then at least people trained to symptoms should be on-site.

as a condition to major cause of recognize well

4. With reference to Figure 2, we would recommend eliminating the rupture disk because it could lead to a sudden, possibly harmful discharge. If the pipe ram on the bottom of the stack is closed, there is no access to the annulus. We al~o qu~:?stit:·~ t~P. £'?ar.;ib.i.J it:y 0f a :rt?motely r!ont:!:"olled 12 11

valve on the blooie line because of the hydraulics involved. A consolidated hydraulic system to operate 8 separate valves might be rare and expensive to rent.

Thank you for the opportunity to comment. Happy New Year.

Y?-"9 truly, ,/

//-~~ Vice-Pksident

We wish you a

725 Farmers Lane • PO- Box 1236 • Santa Rosa, California 95402 • (707) 523-2960 • FAX (707) 523-1029

Water Resourc( International. Inc.

Mr. Manabu Tagamori Manager-Chief Engineer Dept. of Land & Natural P.O. Box 373 Honolulu, Hawaii 96809

Resources

Subject: GEOTHERMAL BLOWOUT MANUAL

Dear Mr. Tagamori,

December 17, 1992

I received your Geothermal Blowout Manual. After reading it, I would like to suggest the following to be considered, as I believe these items to be very important.

1. The drilled hole must be surveyed as the hole is being drilled. This is necessary in order to drill an offset well to kill any well that has no capability to be killed from the original hole. You know the ramifications if one well ever blows out and we are not able to plug it because we didn't take all possible precautions.

2. The final cemented liner casing must be checked for damages. This is very important as the casing is subject to a lot of local wear, especially in a direction hole.

3. I think that serious thought should be given to completely enclosing the drill site so that no noise would escape due to drilling, unloading trucks, etc.

Should you have any further questions regarding my suggestions, I would be more than happy to discuss them in detail with you. I can be reached at the following Hilo phone number, 959-3852, during the next two weeks, as our Hilo office will be shut down for the holidays.

Yours truly,

aivt!1o u)ai:iJu..JV

t w.~. ~addick Sr. Vice President

WRC/kw

2828 Paa Street • Suite 2085 • Honolulu, Hawaii 96819 • Telephone (BOB) 839-7727 • Telecopier (808) 833-5577 • Telex 7238672 WAll HR

TEL: Dec 28.92

TEPLOII GEOLOGIC 1901 Harriaon Bt., Suite 1590

Oakland, CA 94612 Tal. 618-763•7&12 ra~ 510-763-2504

Kanabu ta;oaori, Manaver Department ot Land and Hatural Resources P.O. Box 373 Honolulu, HI 96809 P~ ,, ,.,, h,,,.. ~zu, uu

Dear Manabu,

15:26 No.032 P.02

As per your request, I have reviewed the HewaH GeotherDal Blowout Prevention Manual. The rollowing are my coaments•

Lave tube, eah, and rubDl~ contribute primarily to very h19h horizontal permeability whereas vertical permeability ean be extreaely limited and eontrollad primarily br isolated, nearvertical fractures.

2. Page 7, last paragraph "Exploration well"

Recent geophysical work whioh I performed tor PGV !ndicatae that subsurtace ima;ino:r of kS-8 type fJ;acturea may be possible using newly rAfinad gaophy~ical techniques. It appear• from t.hio work ~hat •hallow <~seee· depth) steam•bearinq fractures can be pre.,isely located prior to drilling. Uae of thie technique prior to 4rillin9 may allow tor safer placement of the surface drillino:r location and more detailed planning of the depth to intersection of hioh~pressure fractures, espe<!ially in areee whore no previous drillino:r hae occurred.

If you would like to diacuss these commenta fu•thaJ;, par~ioularly in regard to the geophysics, please give me a call at PGV. tel. 808-965-6233 through January 18. After that I can be reached at tha letterhead address and phone.

DeB~ regard•, 'J'EPLOW Gl!lOLOGIC

~1(~~

~1111~ P.O. Box 418 NABORS LOFI"r.AND DRILLING COMPANY Bakersfield, California 93302

3919 Rosedale Highway Bakersfield, California 93308 805-327-4695 805-327-4311 (Fax)

MR. MANABU TAGOMORI STATE OF HAWAII

December 22, 1992

DEPT. OF LAND AND NATURAL RESOURCES DIVISION OF WATER AND LAND DEVELOPMENT P.O. BOX373 HONOLULU, HAWAII 96809

Dear Mr. Tagomori:

~

:7"> c:: c:; <

;

r .. ~: r )..> ~ ~

' f"""'; 3....::0 ~;>o -i

(f:")

'""' = ,...,., CJ

rv = ;I:>

c..o

c.....:> c:.o

In reply to your request for comments on the draft of the "Hawaii Geothermal Blowout Prevention Manual", the following are my comments.

On Page 30, "Shut in Procedures" #2. WHILE TRIPPING should begin with:

a. Sound Alarm b. Lower drill string to place drill pipe tool joint just above the rotary table or if

drill collars are in preventers, lower drill collars until drill collar box is just above the rotary table.

c. Set slips (install D.C. clamp on D.C.'s) d. Install the full opening safety valve. e. Close the safety valve; close the annular preventer. f. Notify the company supervisor. g. Make up the kelly; open the safety valve. h. Record the drill pipe and annular pressure build up.

If you have any questions regarding my comments, please do not hesitate to contact me.

GA/sk

~L1f~~~~~~~ Gene Anderson Division Superintendent

. .,. .. ,....:...:

jT• ,--, ' '

' ..• -i

' ,,

;··n 0

STATE OF rb· -

'16

'\l'll'lf}e -tt,'('.~'(\ee~ _,1J Tagomo r i ye'e 0 G3' ~ OF HAWA I I o"~ utPARTHENT OF LAND AND NATURAL RESOURCES

Division of Water and Land Development PO Box 373 Honolulu, HI 96809

Dear Hr. Tagomori,

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December 10, 1992

I have received a copy of your geothermal BOP manual, and it looks like Herb Wheeler eta! have done a very good job for you. However, Dick Thomas, our geothermal officer in Sacramento and one of the authors of the technical investigation report that resulted in your contracting for the manual, thinks that there are a few areas in which I may be able to provide information of possible use before your manual is finalized.

To introduce myself, I am the Wygle of "Hallmark and Wygle" mentioned in the references section of your manual as having written the BOPE book for the State of California. I have taught at the HHS-approved, WOGA/IADC well control school at Ventura College, so I can probably hold my own in a discussion of oil and gas well blowout prevention, but I will be the first to admit that my actual experience with geothermal blowouts is extremely limited. I will, therefore, make no effort to pass myself off as any sort of an "expert" in the field.

The references section of your manual cites the 2nd edition (1978) of Manual H07, but we are up to the 5th edition (1985> and are about to produce the 6th edition in which we intend to expand our efforts along the geothermal line.

I am enclosing a draft of the geothermal section of the 6th edition. This change contains our first effort to classify geothermal BOPE so that we can require equipment that is tailored to the situation presented by a specific drilling proposal. This gives us a little more latitude than that indicated in your proposed manual, which shows only a diverter system and a "Cadillac" system.

I'm a little bit concerned about the fact that your proposed manual doesn't make a bigger deal of the value of cold water in geothermal kick response. It is mentioned late in the first paragraph on page

CALIFORNIA DIVISION OF OIL AND GAS December 10, 1992 SUBJECT: Hawaii Geothermal Blowout Prevention Manual Page 2 of 2 Pages

22, but cold water always seems to be the first thing that is mentioned when I have asked people in the geothermal or steam injection business about their plans for kick control. It is not mentioned at all in the KICK KILL PROCEDURES section on page 31.

Also, I think you should consider outlining shut-in procedures to be followed when drill collars are in the preventers. This possibility is not mentioned among the choices in the SHUT IN PROCEDURES section on pages 30 and 31, but kicks taken at this critical point in pipe-pulling operations have caused some of the major blowouts in recent history.

My only other comment at the moment has to do with a consistent typographic error in the manual. In the term H2 S, the "2" is consistently superscripted as a power instead of subscripted as a term in a chemical formula should be.

I hope I have responded as you asked in your cover letter that I should. If there is any other help I can provide, please call me at the phone number in the letterhead.

Regards,

·~ Pete Wygle Energy and Mineral Resources Engineer

4 GEOTHERMAL EQUIPMENT DESCRIPTIONS, OPERATING CHARACTERISTICS, AND REQUIREI'lEN'l:'S

4-1. GENERAL

a. BOPE requirements for geothermal wells differ from well to well, depending on the type of geothermal reservoir being drilled, as well as differing in many ways from those for oil and gas wells.

In most high temperature geothermal wells, surface pressures are quite low, reducing the need for the high pressure-rating requirements for BOPE that are frequently necessary when operating in oil and gas reservoirs. On the other hand, geothermal flow volumes and rates are often quite high at the surface, necessitating larger diameter choke, vent, and flow-line diameters than would normally be necessary for an oil and gas well with a low-pressure BOPE determination.

Special problems are encountered in drilling and completing geothermal wells, and special equipment has been developed to deal with these problems. In addition, specification terminology is sometimes different from that used when referring to oilfield equipment. For instance, geothermal wellhead equipment, such as side outlet valves and master valves, are usually built to American National standards Institute {ANSI) specifications rather than American Petroleum Institute {API) specifications .

If a particular geothermal well BOPE situation is not addressed in this section, the Division's requirements will be the same as those for comparable oil and gas wells.

4-2 TYPES OF GEOTHERMAL RESERVOIRS: There are two major categories and several subcategories of geothermal reservoirs.

a. High temperature reservoirs. Reservoirs in which the produced fluids are above the boiling temperature of water at the local atmospheric pressure.

1.. Hot, dry reservoirs. A hot reservoir with little or no producible interstitial water. There is little chance of a blowout from this type of reservoir except from the flashing of liquids being used in the circulating system or those that have been injected into the formation. In either case, the blowout would be of short duration. However, when drilling a hot, dry reservoir, BOPE similar to that used for any other high-temperature system is required because pockets of fluid might be encountered.

2. Vapor-dominated reservoirs. A reservoir in which the formation fluid is in the vapor phase. After drilling to a point above the reservoir using mud as the circulating fluid, the reservoir itself is usually drilled with air. Drilling conditions are similar to those encountered when drilling during a controlled blowout, as

)

there is no drilling mud to provide blowout protection or the usual warning signs of a kick. Vapor-dominated reservoirs present conditions that are very different from those encountered in oil and gas reservoirs; subsequently, there are many differences in the drilling methods and BOPE requirements.

3. water-dominated reservoirs. A reservoir in which the formation fluid is in the liquid phase. Because the water entering the well bore from the formation is in the liquid phase at least part of the time, the conditions are very similar to those encountered when drilling through high-pressure saltwater zones in oil and gas fields, and the requirements for BOPE are similar. However, precautions are necessary because the hot reservoir water may flash to steam in the well bore while being circulated out of the well.

b. Low-temperature reservoirs. A reservoir in which the temperature of the produced water is below the boiling point of water at the local atmospheric pressure. Drilling conditions are very similar to those encountered in oil and gas drilling and the requirements for BOPE are identical. The operator is responsible for developing and following safe practices for handling the circulating fluids because they may be very different from those used for oil- and gas-well drilling.

4-3 BOPE DESCRIPTIONS AND REQUIREMENTS

a. High-Temperature Reservoirs

1. General.

a) Elastomer components (e. g. preventer packing elements, ram seals, etc.) must be made of a material formulated specifically to tolerate a steam or hot-water environment.

b) Although it is not a requirement of the Division, some operators prefer to install all-steel rams in place of normal ram assemblies (which are equipped with elastomer seals) in ram-type preventers installed immediately below, or above, the banjo box.

c) Pressure-control equipment must conform to the provisions of Section 3 of this manual.

d) The equipment requirements outlined in this section are mandatory for most wells drilled into high-temperature reservoirs, either vapor-dominated or liquid-dominated, but exceptions may be made on a well-by-well basis, depending on well and geologic conditions.

2. Descriptions of components Unique to Geothermal BOP stacks. (See Figure 24) BOPE stacks used for wells drilled with air in a high-temperature hydrothermal reservoir include some or all of the following devices not commonly used in oil- and gas-well drilling:

,)

a) Slab Gate. An optional, hydraulically operated, singlegate blind ram that is mounted above the permanent wellhead equipment and serves as the lowest element in the BOPE stack. Because a slab gate must be able to function satisfactorily over a wide range of temperatures, the close tolerances and elastomer seal-surfaces found in normal ram-type preventers cannot be used and a complete seal cannot be expected from the slab gate .. This valve is used as a working valve when the drill string is out of the hole. ·

If used, the slab gate is installed above the manually operated, gate-type control valve that is a component of the permanent completion system. The manually operated control valve is capable of a complete seal.

b) Banjo Box. A tee or box with a side outlet that redirects the flow of vapors, liquids, and drilled solids from the well bore to the blooie line. Frequently, the banjo box has a large chamber that will dissipate some energy of the steam or other vapors from the well bore.

c) Blooie Line. A large-diameter line that transfers the flow of well fluids from the banjo box to the muffler and separator when drilling with air. If portions of the hole are being drilled with mud or water as a circulating fluid, the blooie line may be closed off with a blanking plate or gate valve at the outlet from the banjo box, thereby directing the circulating fluid to the flow-line outlet of the rotating head (see f) below). If a gate valve is used, provision shall be made for a secure platform or other means of ensuring the safety of anyone attempting to operate it. (The Division does regulate the selection and arrangement of components of the blooie-line system downstream of the control valve or blanking plate.)

The blooie line should have as few turns in it as practicable, and may have several ports that are used to inject liquids into the air-steam flow. The liquids help in removing drill cuttings removal and in hydrogen-sulfide abatement, if necessary. The choke line may also be vented into the blooie line through one of the ports.

Except for the fact that it operates full-time, the blooie line, together with the muffler and separator (see d) and e) below), perform the same function as the diverter system used in oil- and gas-well drilling.

d) Muffler. A larger-diameter section of the blooie line that reduces the noise of the expelled vapors.

e) Separator. A vertical, cyclone-type device at the end of the blooie-linejmuffler system that separates the cuttings and liquids from the vapors. The vapors escape to the atmosphere from the top of the muffler and the cuttings and liquids are

expelled from the bottom. The separator is similar to the mudgas separator common in oil- and gas-well drilling operations.

f) Rotating Head. A device consisting of an outer housing that is flanged to the uppermost preventer and an inner, bearing-mounted stripper-packer assembly that rotates with the kelly. During normal air-drilling operations, the packer acts as a seal against flowing pressures to keep air, steam, and cuttings away from the rig floor. Normally, the rotating head must be cooled to protect the elastomer seals.

3. Equipment Requirements

a) When Using Air as a Circulating Fluid (Equipment Classification HAl. During the periods when air is used as the circulating fluid in a well being drilled into a hightemperature reservoir, the well must be equipped with the following (minimum) BOPE, listed from top to bottom (see Fig. 24) :

1) A rotating head. 2) A double-ram (pipe and blind) blowout preventer or equivalent equipped with high temperature seals. 3) A banjo-boxjblooie-line system, or approved substitute. 4) A full-closing gate-type control valve installed between the wellhead and the preventerjbanjo box stack. 5) A kill line of 2-inch (minimum) ID with a check valve and at least one gate-, ball-, or plug-type control valve installed as close to the wellhead as is practicable. 6) A blowdown line with a 3-inch (minimum) ID and at least two gate, ball, or plug valves installed as close to the wellhead as is practicable. The line must be anchored securely at all bends and as close to the exhaust outlet as is practicable. As an alternative to an anchored line leading away from the well bore, the blowdown-line may be connected to one of the ports on the blooie line.

At the operator's option, the stack may be equipped with a slab gate and all-steel pipe rams between the required full-closing control valve and the banjo box.

Equivalent systems may be approved by the district engineer.

b) When Using Mud or water as a circulating Fluid. Equipment requirements will vary (as is discussed below) depending upon which casing string is serving as the anchor string for the BOP stack and the type of fluid being used to circulate the cuttings out of the hole. Normally, wells drilled into waterdominated geothermal reservoirs are drilled with drilling mud; however, some may be drilled completely with air, while others are drilled partially with mud and partially with air for certain intervals.

)

=-------

1) Diverter system Requirements for the conductor casing !Equipment Classification HD). A diverter system is not designed to shut in or halt flow, but rather to route the flow to a safe distance away from the rig floor if a blowout occurs before deeper casing is cemented (See Section 2 for selection of equipment). Before drilling out the shoe of the conductgr pipe, the Division will require the following diverter-system equipment unless the operator can demonstrate that such equipment is not . needed.

a. At least one diverter. This diverter may be any one, or combination, of the following devices:

1. A rotating stripper head 2. A remote-controlled, hydraulically operated annular preventer 3. A substitute device approved in advance by the Division.

b. A large-diameter vent line into the wellbore below the diverter required by a., above. A 6-inch or larger ID line is recommended. The vent line may be attached to an outlet on the conductor casing itself or on a spool mounted between the conductor casing and the diverter. This line must be directed away from any nearby public road or normally occupied building.

c. A device in, or design of, the vent line that will prevent flow of well fluids through the line during normal well operations, but will open the vent line to permit flow in an emergency. This requirement may be satisfied by either of the following methods:

1. A riser installed in the diverter line with an outlet above the level of the flow line. This would provide an open-flow diverter system (See Figure 13A).

2. A full-opening control valve, with a throughbore at least equal to the ID of the vent line, mounted in the line near the conductor casing. If a manual valve is used, it must be readily accessible and of an easy-opening design. If a remotely operated valve is used, it is suggested that the system be designed so the valve opens automatically as the diverter is closed. To accomplish this in an installation in which the diverter is an annular preventer, a remotely controlled, hydraulically operated valve may be installed in such a way that the opening chamber of the valve is connected to the

0

closing line of the annular preventer. In such an installation, the valve will be pressured open each time the preventer is closed.

2) BOPE Requirements for the surface, Intermediate, and Production Casings (Equipment Classification HMl. Before drilling out the shoe of the surface, intermediate, or production casing during mud or air drilling, ~nstalled blowout prevention equipment must include (at a minimum):

a. An annular preventer or a rotating head. annular preventer is used, it must be equipped hydropneumatic accumulator-actuating system.

If an with a

b. A hydraulically operated double-ram blowout preventer or an approved substitute, with a minimum working-pressure rating that exceeds the maximum anticipated surface pressure (at the expected reservoir fluid temperature).

c. A kill line (2-inch minimum ID) equipped with a check valve and at least one control valve.

d. A choke line, or a blowdown line (3-inch minimum ID) equipped with at least two control valves placed as close to the wellhead as is practicable. The line should be anchored securely at all turns and at the end to prevent whipping or vibration damage during use. As an alternative to an anchored line leading away from the wellbore, the blowdown line may be attached to one of the ports on the blooie line.

The choke and kill lines may be installed on the side openings of the optional slip-type expansion spool, if one is installed, as part of the permanentcompletion wellhead. Such a connection will be permitted only if the side openings of the expansion spool are large enough to accept the lines and if it can be demonstrated to the satisfaction of the Division that egress of fluids from the well bore will not be blocked by linear expansion of the inner string(s) of casing . • e. A full-closing gate-type control valve installed between the wellhead and the preventerjbanjo-box stack.

f. A choke manifold will be required in the following cases:

1. When drilling an exploratory (prospect) well. 2. In those cases where gas is known to exist.

.. )

3. In those cases where abrasive wellbore fluids might be encountered.

The manifold must be equipped with at least one adjustable choke, a blowdown line (with an ID at least as large as the ID of the choke line), and an accurate pressure gauge. The choke should be of the multiple-orifice type or the cylindrical-gate-andseat type. A remote-controlled choke is preferable to one that is controlled manually.

c) When Using Mud/Water and Air Intermittently as a Circulating Medium (Equipment Classification HMAl. In addition to the BOPE required in subparagraph b) above, the following additional BOPE is required when a well is being drilled with air or another gaseous fluid:

1) A banjo box or approved substitute below the preventers.

2) A blooie-linejmufflerjseparator system.

3) A slab gate andjor ram-type preventer (equipped with all-steel CSO ram assemblies) may be installed between the banjo box and the full-closing control valve required in paragraph 4-Ja3b)2)e above.

d) Heat Exchanger or Mud cooler. When the reservoir is being drilled with mud as the circulating fluid, mud-cooling devices must be used when the temperature of the mud at the flow line is anticipated to be higher than the flash point for a continuous period of more than one hour.

4. Drilling Fluid Requirements. If a well is being drilled intermittently with mud and air, an adequate source of water or drilling mud and weight materials to ensure well control must be readily accessible at the drill site for use at all times when the well is being drilled with air

b. Low-Temperature Reservoirs. Following are the BOPE requirements for low-temperature and temperature-observation wells drilled in high heatflow areas not previously drilled, or areas having a moderate to high potential for blowouts:

1. Equipment Classification LP (see Fig. 25):

a) An annular preventer andjor pipe- and blind-ram preventers.

b) A kill line and a blow-down line installed below the preventer .

2. Equipment Classification LD (see Fig. 26). In areas where geological conditions are known and where pressures are known to be

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at or below hydrostatic pressure, approval may be given for the use of a single diverter stack with a flow line installed below a blowout preventer, gate valve, rotating head, or approved (equivalent) device.

All required low-temperature BOPE equipment must be fully operational at all times. Pressure-control equipment must conform to provisions in Section 3 of this manual.

4-4 RELATED WELL-CONTROL EQUIPMENT (Auxiliary Equipment). In addition to the requirements listed in Section 4-3 above, the following BOPE must be considered for all wells drilled in known or suspected geothermal resource areas. ·

a. A full-opening safety valve (sized to the working string in use) maintained in the open position on the rig floor at all times while drilling operations are being conducted, and when running casing. While tripping pipe during drilling operations, an operator may choose to make up the valve on the pin end of a joint of drill pipe that is kept readily available for stabbing into the working string. This procedure makes it unnecessary for the rig crew to pick up the valve and attempt to stab it by hand. Also, the hot fluids coming up the working string will be expelled above the crew rather than at the working level.

b. An upper kelly cock installed between the kelly and the swivel. If the uppermost item in the BOP stack is not a rotating head, a lower kelly cock may be used.

c. An internal preventer readily available to the rig crew whenever the well is being drilled with mud or water as a circulating medium.

4-5 BOPE TESTING, INSPECTION, TRAINING, AND MAINTENANCE

a. Testing. The annular and ram-type blowout preventers, the actuating system, and the auxiliary equipment must be tested in accordance with the provisions outlined in Section 5 of this manual; however, pressuretesting of any all-steel ram or gate is not required;

b. Inspection and Actuation. All required BOPE must be inspected and, if applicable, actuated periodically to ensure operational readiness. The minimum frequency of this inspection/actuation is as follows:

1. Once each eight-hour tour, the following are to be performed:

a) Check the accumulator pressure. b) Check the pressure of the emergency backup system. c) Check the hydraulic fluid level in the accumulator unit reservoir. d) Actuate all audible and visual indicators and alarms.

2. Once each trip, but not more often than once every 24 hours, the following are to be actuated:

)

u

a) Pipe rams (before starting out of the hole). b) Blind (CSO) rams (after pulling the pipe from the hole). c) All kelly cocks. d) Drill pipe safety valve. e) Internal Preventer (if required). f) Adjustable chokes (if required). g) Hydraulic control valves (if any).

' 3. Once each seven days, the following are to be actuated:

a) The annular preventer (if installed) on drill pipe or tubing. b) All gate valves in the kill and choke systems. c) The full-closing control valve on the wellhead.

Also, the flange bolts or studs at all preventer and wellhead connections must be tested for tightness every seven days.

c. crew Training. BOPE practice drills and training sessions must be conducted at least once each week for each crew, and may be performed in conjunction with the operational~readiness tests outlined in paragraph 4-5b. Training must be such that each member of the crew has, at a minimum, the following:

1. A clear understanding of the purpose and the method of operation of each preventer and all associated equipment.

2. The ability to recognize the warning signs that accompany a well kick or steam blowout.

3. A clear understanding of each crew member's station and duties in the event of a kick or steam blowout while drilling, tripping pipe, while drill collars are in the preventers, and while out of the hole.

d. Records. A record of all inspections, tests, crew drills, and training sessions must be kept in the daily log book.

e. Maintenance. All equipment must be maintained in accordance with the manufacturer's recommendations andfor the requirements of this manual.

rta/ 0-l/1 '393 ·1 5: 32 . 808-252-5350 R. A. F·ATTERSO!'l & ASSO

,.

R. A. PATTBRSQN & ~PSQQ±ATES 1274 Xika Street Kailua, Hawa1 96734-4521 (808} 262-5651 (808) 262-5350(FAX)

FACSIM::r:r~E COVER SEIEE'r

~~ .. ~:~~ .:. ~·G:· ~ .... ,,.~, ~~ ~~

(~ ~qo

TO: ______ DIVISION OF WATER AND LAND DEVELOPMENT - DLNR ______ ~_

ATTENTION: ___ .JON FLORES·------

FROM: ___ RALPH PATTERSON

SUBJ : ____ SCHflOUU; ___________ _

NO. OF' PAGES INCLUDING COVER SHEET: _____ 2 _____ _

DATE SENT: __ August 4, 199 3 ________ _

Please call if you have a problem with receipt.

JON - PLEASE REVIEW AND DELIVER. WILL MAIL A COPY TOMORROW.

R. A. PAT1 E.RSU~l & A::;~:,O

B. A._ PATTE ...::2.Qlf & A§f:SQC::IA"J..' ii 1274 Kika street · KailuA, Hawai~ 96734-4521

August 4, 1993

Mr. Gordon Akita Department of Land & Natural Resources Division of Water and Land Development P. 0. Box 373 Honolulu, Hl 96809

Dear Mr. Akita;

PAGE. 02

Subsequent to Mr. 'l'agOlDOri 's letter of .July 27th. we have had discussions with OOWALD staff that point toward a different schedule for completing our work on the "Hawaii Geothermal Blowout l'revAntion Manual," and the "Hawaii Geothermal Drilling Guide."

we underst ... nd that a review of the "Blowout Prevention Manual" has indicated that there are :.ome paqes that will need replacing <lulil to typoqraphical errors; when these have been identified, we will reprint the pages and provide them to you. The two bound copies will have replacement pages inserted in the copies.

The draft copy of the "Drill inq Guide" has been submitted for review and comment; since these comments have not yet been received, we wi 11 be unable to deliver the final version on August 6, 1993 , as outlined ln your letter.

We will be glad to expedite the above "orrections and deliveries, but will have to have a reasonable time to make t.he corrections and do the printing and binding when the st:aft reviews are compl .. ted.

'rhe tinal versions of thu documents and diskette files will be delivered, and the presentations to staff and the Geotechnical Advisory committee scheduled as soon as possi.ble.

cc: Mr. Kanabu Tagomorl Mr. Jon Floras

R. A. PATTERSON& ASSOCIATES , 1274 Kika Street Ka1lua, Hawaii 96734-452:

(808) 262-5651 (808) 262-5350 (FAX)

September 20, 1993

Mr. Manabu Tagomori Department of Land & Natural Resources Division of Water and Land Development P. 0. Box 373 Honolulu, HI 96809

Dear Mr. Tagomori;



We have made the changes and corrections requested in your letter of September 7, 19 3 3. However, we remain concerned that the DLNRdesired wording describing the optional BOP stack configuration, (Section IV, page 17) would create a hazardous situation in the event of another failure of the wing valves (similar to that which occurred at the KS-1 well in October 1982). If the wing valves are below the ram preventer, an important safety back-up would be missing in the event that the small valves fail or need repair; there would be no l.ast resort to preventing a blowout in this area of the stack.



enclosures cc: RCUH (letter only)

Note:

CORRECTIONS. FO~IN.AL ~AW~II BLOWOUT PREVENTION MANUAL

A [c( ~"-'-'"taR c~<IM, W&~ IJIYI.a(2& 4:f. Please see mark-up copy of the Manual for a reference to the requested changes.

Text to be deleted is in [brackets]

Text to be added is underlined

Please make the following corrections:

.....-2.

Page after cover sheet, listing BLNR members and government officials: Misspelled KEPPELER.

Acknowledgement Page, bottom of first paragraph: Misspelled Tagomori.

~3. Preface Page, middle of third paragraph: Delete [and], add an; Misspelled State.

v4. Page 5, second paragraph: Please write as:

~-

Primary features such as lava tubes, irregular layers of ash and rubble contibute to very high horizontal permeability, whereas secondary features such as fractures contibute to very high vertical permeability; both features can pose a problem with loss of drilling fluid circulation and low rock strengths. These features seem to diminish downward, but appear to extend to depths of about 2000 feet.

Page 10, third paragraph, line 6: Delete [Commonly] from the beginning of the sentence; add commonly to line 7.

Example: The deliberate actions to optomize safety in geothermal drilling commonly will be specified or reflected in four distinct sections of the drilling plan, as follows:

~- Page 15, second paragraph, line 5: add while the drill string is.

Example: situations such as active drilling and tripping, or while the drill string is out of the hole.

~- Page 17, last line: Delete [Another possible arrangement might omit (continued on page 18) the ram preventer shown below the choke and fill line valves, saving the height of this valve. This would remove an important safety back-up in the event that the small valves fail or need repair; without this ram preventer there would be no last resort to preventing a

1

.. ,.

blowout in this area of the stack.]; add:

Another possible arrangement is to remove the lowermost pipe ram shown in Figure 2 and install it above the choke and kill lines, in tandem with the blind ram. A full BOP stack should be maintained at all times while drilling in the vicinity of the production zone.

~. Page 24, bottom paragraph, line 6: add way.

...A.

t-Jo 10.

Example: The imformation provided by way of monitoring procedures, with careful integration and evaluation, can make iportant contributions to an Operator's prevention strategy .

Page 27, last paragrpah, line 11: delete space to the left of the word "where" .

Page 29, first paragraph, line 2: delete spaces after ''events'', ''on'', ''other'', and before and after ''A''.

·,/1:'1. Page 32, bottom of page: underline Driller and Logger and format as follows:

Driller drilling penetration rate drilling fluid circulation

Logger temperature variations secondary mineralization formation fluid entries

~2. Page 45, last paragraph, line 7: Delete space in middle of paragraph.

03. Appendix A-1, Manual Review and Revision: delete the last paragraph.

~4. Appendix C-1, References:

va:s.

References 3 and 10: change superscripted 2 in H2 S to subscript. Example: H2 S

Reference 12: delete [Geothermal] at the end of the first line; add Geothermal at the beginning of the reference.

Example: Geothermal Regulations and Rules of Practice &

Procedure, State of Nevada.

Appendix C-2, line 2 "Sumida,Gerald, A.": delete

2

of reference [and] ; add an.

beginning with

Example: Sumida, Gerald A., Alternative Approaches to the Legal, Institutional and Financial Aspects of Developing an Inter-Island Electrical Transmission Cable System.

~- Appendix D-2, Glossary:

v First paragraph: add a period (.) after "surface".

Definition of casing: add or injection; delete [from the well] :

vExample: casing n. steel pipe, cemented in the wellbore to protect it against external fluids and rock conditions, and to facilitate the reliable and safe production or injection of geothermal fluids.

~lete second definition of casing.

~ Appendix D-5, Definition of pipe ram: delete [and]; add ££ill and ram.

Example: See ram and ram blowout preventer.

3

HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL

State of Hawaii DEPARTMENT OF LAND AND NATURAL RESOURCES

Division of Water and Land Development

JOHN WAIHEE Governor


KEITH W. AHUE, Chairperson

SHARON R. HIHENO, Member at Large

MICHAEL H. HEKOBA, Oahu Member

HERBERT K. APAKA, .JR., Kauai Member

WILLIAM KENNISON, Maui Member

CHRISTOPHER J. YUEH, Hawaii Member

DEPARTMENT OF LAND AHD NATURAL RESOQRCES

KEITH w. AHUE, Chairperson

JOHN P. KEPPELER II, Deputy

DOHA L. HAHAIKE, Deputy

DiviSION OF WATER AND LAMP DEVELQPMEMT

MAHABU TAGOMORI, P. E., Manager- Chief Engineer

ACKNOWLEDGEMENT

This document was prepared by R. A. Patterson & Associates, Kailua, Hawaii, for the Hawaii Department of Land and Natural Resources under Contract Agreement No. RCUH P. o. 4361021. The work was performed by Ralph A. Patterson, William L. D'Olier, and Herbert E. Wheeler. We wish to gratefully acknowledge the assistance of the staff of the Division of water and Land Developaent, under the direction of Manabu Tagomori, and of the invaluable suggestions and assistance of all those who discussed the project with us.

Development of this Manual would not have been possible without the willing cooperation of many managers, technicians and professionals in the geothermal industry, various laboratories and academic institutions, and in other areas where their knowledge was helpful in presenting the review and recommendations of the Manual. The authors wish to acknowledge their help and candor, and their accumulated knowledge that has made our job easier.

PREFACE

The prevention of an uncontrolled well flow, commonly known as

a "blowout", is of vi tal importance for geothermal operators, drilling

crews, state and county regulators, and the general public. Geothermal

well blowouts have not been the cause of a significant number of

fatalities, and the danger of fire, as in petroleum drilling, is quite

low. However, blowout incidents may have a negative impact on surface

and subsurface environments, cause resource waste, and develop

unfavorable public perceptions of geothermal activity. These concerns

are powerful incentives to operators and regulators to minimize the

risks of a blowout.

This Manual has been developed to promote safety and good

resource management by discussing and describing blowout prevention

as it can best be practiced in Hawaii.

The intent of this Manual is to provide the necessary information

to guide regulators and operators in the practices and procedures,

appropriate to each drilling situation, that will minimize the risks

of a blowout. The Manual is also intended to promote an informed

flexibility in blowout prevention practices, and to supplement State

and County regulations, especially those pertaining directly to

drilling permits and operations.'

This first edition of the Blowout Prevention Manual is a likely

candidate for revision as more drilling experience and information is

gathered in the exploration and development of Hawaii's geothermal

resources.

1 Department of Land and Natural resources (DLNR) Title 13, Subtitle 7. Water and Land Development; Chapter 183.

CONTENTS

Acknowledgement

Preface

YL.

YI.L.

VIII.

l..lL..

x.._

XL.

SCOPE

GEOTHERMAL DRILLING RISKS IN ijAWAII

GEOTHERMAL WELL PLANNING

BLOwoUT PREVENTION STACKS AND EQUIPMENT

EQUIPMENT TESTING AND INSPECTION

DRILLING MQNITORING PROCEDURES

KICK CONTROL

BLOWOUT CLASSIFICATION

SUPERYISION ANQ TBAINING

POST COMPLETION BLOWOUT PREVENTION

BLOWOUT PREVENTION IN SLIM HOLES

APPENDICES

A - Procedures for Manual Review and Revisions

B - Illustrations

c - References

D - Glossary

i

Page

l

2

6

13

20

22

34

37

39

42

43

I. SCOPE

The material in this Manual has been extracted from many key

information sources in order to present a complete and accurate review

of the practices of geothermal well control in Hawaii. In developing

this Manual, a careful review of drilling to date in the Kilauea East

Rift Zone (KERZ) was conducted. The KERZ is where nearly all Hawaii

geothermal drilling has taken place, and is where most experts believe

the geothermal resources will be developed.

The general belief in the industry is that each area is "unique",

since each prospective geothermal area throughout the world has proven

to have its own characteristics in terms of drilling conditions,

resource chemistry, geology, etc. While this may be true in detail,

some similarities do exist among geothermal areas located in, or

nearby, active volcanic areas. Thus, it has been helpful to briefly

review well control techniques and experiences from other similar

volcanic areas around the world. some of the information gathered may

have an influence on geothermal drilling in Hawaii.

In order to review the experiences in Hawaii and in other

geothermal areas where active vulcanism is prevalent, a great number

of specific publications and selected references were consulted. Many

of these are listed in Appendix c, References. In addition, much of

the information and many recommendations contained in this Manual came

from the accumulated experience of others who were consulted on

various elements of the items presented. A partial list of those

consulted is also contained in Appendix c.

This Manual defines a blowout prevention strategy for geothermal

drilling in the State of Hawaii. The essential co•ponents of this

strategy

1)

2)

are:

!~roved risk analysis and well planning.

SOund selection of blowout prevention stacks and associated

equipaent.

J) Rigorous use of drilling monitoring procedures.

4) Expertise in kick control and blowout prevention equipment

utilization.

5) Excellence in supervision and training of drilling

personnel.

1

II GE,\1THERMAL DRILLING RISKS 1.1 HAWAII

THE VOLCANIC DOMAIN

The State of Hawaii consists of a chain of volcanic islands.

Each island is a composite of several volcanic eruptive centers built

up by a succession of basaltic lava flows, first as submarine deposits

and subsequently as volcanic lands (or subaerial deposits.) These

basaltic lava flows form a sequence of near horizontal layers

consisting of hard crystalline flow rocks interbedded with lesser

amounts of highly variable rock debris. These flow sequences are

evident in extensive outcrops and in lithology logs from water well

drilling.

Recently recognized geothermal resources in Hawaii are

characterized by relatively small prospective areas which are strongly

associated with active or recent volcanism. The highest probability

areas for geothermal development overlie the volcanic rift zones which

are, or recently were, deep conduits for magma transport away from the

volcanic eruptive center. Hawaiian geothermal drilling to date has

been confined to the active Kilauea East Rift Zone (KERZ). In the

KERZ, the magma and lava processes (1900°F and higher) provide very

high subsurface temperatures. Large amounts of meteoric water

(groundwater) and seawater intrude into the KERZ geothermal resource

zones, providing an abundant fluid supply for heat transfer.

Geothermal drilling in Hawaiian rift zones involves distinctive

risks. A reasonable initial identification of hazards and risks is now

possible due to KERZ drilling experience, combined with extensive

studies by the Hawaii Volcano Observatory (HVO) of KERZ rift zone

function, structure and dynamic processes.

knowledge can be used to refine geothermal

This experience and

drilling programs and

procedures to minimize the risks of upsets and blowouts.

KERZ DRILLING TO DATE

The most valuable subsurface information for this Blowout

2

Prevention Manua... comes from 12 deep geot •• armal wells and three

exploratory slimholes drilled in the KERZ since 1975. Rotary drilling

rigs appropriate to the drilling objectives were used on the twelve

geothermal wells. Common drilling fluids used in this rotary drilling

are mud, water, aerated fluids and air. The well depths range between

1,670 and 12,500 feet below the ground surface. Operators for the

well drilling included four private resource companies and one public

sector research unit.

As of mid 1992, nine wells had penetrated prospective high

temperature rocks and seven of these were flow tested or manifested

high temperature fluids. The resource discovery well, HGP-A, completed

in mid-1976, provided steam to a 3MW demonstration electrical

generation plant between 1981 and 1990. Two of the nine wells incurred

casing contained blowouts in 1991 upon unexpectedly encountering high

pressured geothermal fluids at shallow depths.

Three deep scientific observation holes (SOH) were drilled for

resource evaluation as continuously cored exploratory slimholes to

5,500-6,800 foot depths in 1990 and 1991. These SOHs helped to prove

that favorable high temperatures prevail over a ten mile interval

along the KERZ. These holes did not encounter subsurface conditions

that involved significant blowout risks; however, special blowout

prevention equipment must be considered for future use of the slimhole

technology in Hawaii.

SUBSURFACE CONDITIONS IN PROSPECTIVE AREAS

High temperatures, commonly in the 600-700"F range, are

characteristic of production zones in the volcanically active rift

zones. The prospective geothermal reservoir occurs in the roof rock

above .the deeper magma conduits. The well completion targets are loci

of permeable, highly conductive fault and fracture zones which are

secondary mineralization. Magma generally enclosed by extensive

transport downrift and its planar injection upward into the roof rock

are the primary heat sources for the geothermal resource.

3

The pr~mary hazard of geothenual drilling in the

volcanically active KERZ is the currently unpredictable distribution

of fault planes and major fractures. The walls of these geologic

structures are commonly sealed by secondary mineralization; thus

creating conduits for geothermal fluids. These fault and fracture

conduits, can present pressures in the range of 500 to 750 psi above

normal hydrostatic pressure, particularly as they extend upward into

cooler ground water regions. Unexpected entry into such over

pressured fault planes and fractures can cause substantial upsets to

all well control procedures.

Primary features such as lava tubes, irregular layers of ash,

and rubble contribute to very high horizontal permeability, whereas

secondary features such as fractures contribute to very high vertical

permeability; both features can pose a problem with loss of drilling

fluid circulation and low rock strengths. These features seem to

diminish downward, but appear to extend to depths of about 2000 feet.

An important feature of the KERZ is the seaward slip-faulting of

its southeastern flank caused by cross rift extensional stress. This

seaward sliding of the roof rock, coupled with seismicity, results in

mol ten dike intrusions and fracturing. Dike intrusions allow an

abundant supply of heating and create prospective fracturing for the

geothermal reservoir. All these features further contribute to low

rock strengths in shallow, near surface volcanics, which can be a

problem when attempting to locate a sound anchor for wellhead blowout

prevention equipment.

The geohydrology of the KERZ involves large volumes of

groundwater and seawater. The relatively cool groundwater body,

located just above sea level, is maintained by high annual rainfall

and a high rate of infiltration. The KERZ geothermal fluid system also

may be fed by a major groundwater basin on Mauna Loa's eastern flank.

Large volumes of seawater have the potential to penetrate the

geothermal reservoir through fractures at depth. Earthquakes in the

region may cause existing fractures to widen or may create new

fractures. An increase in the salinity of the fluids produced by the

4

HGP-A well may hav~ been caused by earthquake ~nduced fractures. High

hydrostatic pressures prevail in active rift zones, but these can be

escalated to higher fluid pressures in the temperature conditions

prevailing. The fresh and saline groundwater body, shown to exist as

deep as 2,500 feet in the Puna geothermal field, may prove to be a

common condition, but not one that can be expected at every proposed

well location.

SUMMARY

The KERZ geothermal drilling experiences prove two significant

hazards that must be addressed in a blowout prevention strategy for

every proposed well:

l. Significant fault and fracture planes can be sealed conduits

for overpressured geothermal fluids. These features might

eventually prove to be predictable or detectable by drilling

precursors. Blowout prevention planning, equipments and

procedures must be taken as a critical requirement, ready

for immediate and proficient use.

2. Weak and broken near surface volcanic rocks. The recognition

of this condition is a precursor to obtaining a reliable

casing anchor, which is fundamental to safe blowout

prevention by complete shut off (CSO) of the well.

5

Iii. GEOTHERMALWELL PLA&JCliNG

INTRODUCTION

The proven higher costs and uncertainties of Hawaiian geothermal

drilling operations are sound reasons to make an extraordinary

investment in well planning. Detailed planning is a must for each and

every type of well because of the paucity of subsurface information

and the small base of drilling experience to date. Blowout prevention

is an integral element of geothermal well planning.

WELL PLANNING OBJECTIVES

Safety The concept of safety must be carefully applied for all

workers and activities at the wellsite and for the public. A blowout

prevention strategy is a crucial part of any successful practice of

safety in geothermal drilling; it is a necessity in Hawaii.

Well Function Geothermal wells, if beneficial development is to

be attained, must convey and control very large quantities of fluid

and energy, hopefully for the greater part of the 30-year life that

is expected in electric power systems. The HGP-A discovery well

demonstrated a reasonable performance in the production mode from

1983 to 1990.

Reasonable Cost Hawaiian geothermal wells are in the very costly

category; perhaps $2,500,000 per well is a representative minimal cost

( 1992$) if no significant problems impact a good drilling plan.

Competent planning might cost only 1 or 2% of the total cost of a

successful well.

H1gh quality well planning will assure a greater degree of

safety and improved well functions. Proper well planning will allow

the Operator to be more confident in responding to the upset

conditions that can't be avoided and actual drilling performance can

be better assessed for continued improvements in future Hawaiian

~/fiUJ/IICW..,_ 11, 1993 6

geothermal wells.

DRILLING TARGETS AND WELL TYPES

Geothermal drilling targets in the volcanic realm of Hawaii can

be organized into three simple classifications:

Exploration targets - to discover the resource, are generally

identified by a favorable combination of subsurface data

indicating heat, fluids and fractures (voids). Targets that can

win drilling funds, but which present a high risk exposure, are

usually classified as exploratory by the Operator and

participants.

Reservoir targets - to develop the resource, are generally

qualified by high temperatures, _indicated fault planes and

fracture systems, or by nearby well production data. The

probability of penetrating both high temperatures and fluid

producing permeability intervals is high. Hawaiian geothermal

reservoirs are of the hydrothermal type (the predominate type now

in worldwide utilization.)

SuppleiiE!Iltal targets - to conduct research on the resource , are

comprised of scientific and/or observational objectives which can

contribute to a better understanding of a geothermal resource and

its enclosing subsurface environment.

At the present level of knowledge in Hawaiian rift zones, no

class of geothermal drilling target can be confidently identified to

have lower blowout risks. Off rift geothermal drilling targets may

offer the perception of lower drilling risks, however, no such

drilling has been undertaken as of 1992.

Geothermal wells can be categorized as to function and several

additional features. The common types of wells include the following:

Exploration well. Any well drilled to evaluate a prospective

~/WU)~ 1~. 1112 7

geothermal resource target, usually at svme significant distance

from an established or proven geothermal reservoir. Hard and

proximal subsurface data are not likely to be available for a

blowout prevention plan; diligent drilling monitoring procedures

(see Section VI) and casing plan flexibility are essential to

blowout risk reduction in exploration wells.

Production well. Any well designed to exploit the energy and

fluids of a geothermal reservoir for beneficial use or

demonstration purpose.

wells can be better

subsurface conditions.

Blowout prevention plans for production

specified to more confidently known

Injection well. Any well designed to return geothermal effluent

to the reservoir or other deep disposal zones. Injection wells

will have blowout prevention requirements similar to nearby

production wells.

Slimhole. This type of geothermal well is identified by its

small diameter borehole, 6 to 4 inches, compared to the 17~ -

8~ inch hole diameter range commonly used worldwide in the

geothermal industry. The slimhole technology, presently surging

in evaluation and use in the petroleum industry, has a distinct

blowout risk and prevention requirement. The technology has been

safely introduced in the KERZ when HNEI accomplished three

continuous boreholes between 5500 and 6000 foot total depths in

its Scientific Observation Hole Program (1989-91). Discussion

of the blowout prevention in slimholes is presented in Section

XII.

Deep versus shallow wells. These are terms of convenience in

ioheir general usage; however, regulations may impose a legal

definition on them. A historical point of interest in the KERZ

should be noted; several early geothermal exploration holes,

drilled safely with cable tools, encountered near boiling waters

at very shallow depths next to recent lava flow fissures and

vents. Depth seems to have no correlation with blowout risk in

aot'PL&IDil:aO/IU.D~ 11, lg92 8

Hawaii's geL..:'hermal drilling to date. However, it should be

evident that relatively shallow blowouts in the porous surface

lava rocks and large fissures, broadly prevailing in Hawaii,

could be particularly difficult to kill.

Vertical versus deviated wells. It appears that Hawaiian

geothermal wellfields will be extensively developed with deviated

wellbores. Blowout prevention requirements are not altered in

any type of geothermal well by the vertical or deviated course

of its wellbore.

THE DRILLING PLAN

Every geothermal well proposed for funding and permitting will

require a drilling plan. Regardless of the geothermal well type, the

drilling plan is the specific technical document that should reflect

the best thinking on how the well can be safely constructed and its

function obtained at reasonable cost. Safety is considered on a broad

front in a carefully prepared drilling plan. The deliberate actions

to optimize safety in geothermal drilling commonly will be specified

or reflected in four distinct sections of the drilling plan, as

follows:

1. Casing and cement. The intended function of the proposed

well will be a factor in casing design and cementing

procedures selected. However, the best available subsurface

data sets on geology, hydrology, pressure and temperature

profiles, formation failure thresholds (fracture gradient),

together with the wellsi te elevation, comprise the basis for

increased safety in drilling and quality of construction.

The subsurface conditions and wellsite elevation are unique

to each intended wellbore; the proposed casing and cement

plan must reflect a reasonable response to these conditions.

KERZ drilling experience reveals several special casing

concerns for blowout prevention.

a. A preference to cement the surface casing

9

(Lummonly 20 inch diameter) b~Low the water table can

be acknowledged. Where the groundwater table is within

600-800 feet below the surface, an approximate 1,000

foot length of surface casing would meet this

objective. Where the groundwater table is much deeper,

it could be difficult to obtain a good cement sheath

on surface casing set at, say 1,700 feet, because of

the presence of lost circulation zones and incompetent

rock in which to cement the casing shoe. Prudence

suggests that it is better to obtain a quality cement

sheath on a shorter length of surface casing.

b. Independent of the quality of cement sheath

obtained on surface casing, the possibilities of

fractures, other permeable paths to the surface, and

low formation fracture gradients exist in the near

surface volcanic rocks penetrated by the surface

casing. This points to a serious risk in using a

co•plete shut off (CSO) blowout prevention system on

the surface casing while drilling to the intermediate

casing depth. A CSO could force unexpected hot and

possibly pressured formation fluids to an external

blowout (outside the surface casing and cellar).

External venting of this type can pose more complex and

precarious kill operations, and also threaten the

drilling rig's ground support. Accordingly, a

diverting capacity and large diameter flow line from

the wellhead to a distant disposal point is to be

considered. This approach would contain such an

uncontrolled flow inside the surface casing and afford

a safer kill procedure confined to the wellbore.

c. Intermediate casing (commonly 13-3/8 inch diameter)

may be set at depths between 1, 000-2, 500 feet below the

surface casing shoe if no unexpected geothermal fluids

or anomalies are encountered. The intermediate casing

10

stiue depth should optimallz be below the major

groundwater body. It should also be below extensive

fracturing that may reach up to the groundwater table,

frequent occurrence of lost circulation zones, and less

competent volcanic rock. Because the intermediate

casing becomes the anchor casing for the complete BOP

equipment stack required to drill to total depth, it

is critical that the cement sheath in the open hole

(17~ inch diameter) annulus be of the highest possible

quality. The findings in the 17~ inch drilled hole

should be carefully studied. Any adverse downhole

conditions can be mitigated by cementing the bottom

portion of the intermediate casing as a liner in the

open hole interval (lapped several hundred feet into

the bottom of the surface casing). The upper portion

can be run and cemented as a tie back string inside

the surface casing. Each of the two cement jobs

required should be of enhanced quality, should offset

the external natural hazards and should optimize the

anchor for the complete BOP equipment stack with its

multiple CSO capacity over a full range of drilling

fluids.

2. Drilling fluids. The subsurface conditions encountered

within the KERZ are prompting the use of many drilling

fluids ranging from moderate to low density muds, water,

aerated muds and water, to foam, and air. Additionally, the

ability to switch drilling fluids promptly is being

recognized as a cost effective advantage in greater well

control. This practice demands the use of BOP equipment

compatible with a broad range of drilling fluid options in

a single wellbore. The diversity and flexibility of

drilling fluid utilization in Hawaii is encouraging, not

only because all fluids can be controlled by available BOP

equipment, but because this approach should lead directly

to advanced safety margins, reduced drilling times and lower

&OPPLUIIlJIG/IfLD~ 11, 199:2 11

costs. Drilling fluids and geott.~rmal well control are

further discussed in Section VI.

3. Drilling M9nitoring. This activity

integrated in thorough drilling plans at many

is, however, quite important and deserves more

as an effective method to reduce blowout risks.

is usually

points. It

recognition

A detailed

consideration of drilling monitoring procedures is presented

in Section VI.

4. Blowout Prevention. Drilling plans may contain minimal

specific discussion of blowout prevention; a graphic sketch

of the proposed BOP equipment stack may be the lone obvious

recognition of the subject. However, a competent drilling

plan will reflect, in its detailed provisions, an Operator's

blowout prevention strategy •. The implementation of risk

reduction will be evident in the casing, cementing and

drilling fluid provisions, in the drilling monitoring

procedures, in proper training, and finally in the BOP stack

and its supplemental equipment. The drilling plan should

reveal the Operator's awareness that a blowout~ happen,

and reflect the drilling supervisor's responsible

determination that it has been given the least possible

chance to occur in the proposed well. Blowout prevention is

every Operator's final responsibility; it is achieved first

in the thinking and actions of all drillsite personnel

through training, by the practice of sound procedures, and

by the use of reliable, proper equipment.

BOPPLUIDIG/11l.D~ 11, l99l 12

IY. BLOWOUT PREVENTION STACKS

AND EQUIPMENT

INTRODUCTION

Hawaii's geothermal drilling industry, still in a formative

stage, has gained sufficient experience and information to provide

reasonable guidance to the identification of more reliable and safer

blowout prevention stacks and equipment. The blowout prevention stack

on the wellhead, when all other well control procedures have failed,

must function reliably to obtain a complete closure or effective

control of unexpected fluid flows from the wellbore. Blowout

prevention stacks and related equipment are not simple systems; they

rely on integrated mechanical, hydraulic and electrical processes to

operate. Both redundancy and sophistication exist; however, the risks

of human error in critical situations have not been eliminated.

Blowout prevention systems require careful selection, maintenance, and

repetitive training of drilling crews to attain the reliability and

safety which are essential in the final defense against an actual

blowout.

BOP DEFINITIONS AHD FUNCTIONS

1. Definitions

The term blowout preyention equipment CBOPl here means the

entire array of equipment installed at the well to control kicks and

prevent blowouts. It includes the BOP stack, its activating system,

kill and choke lines and manifolds, kelly cocks, safety valves and all

auxiliary equipment and monitoring devices. (see Glossary in Appendix

D for these terms).

The BQP stack. as

preventers, spools, valves,

wellhead while drilling.

used here, is that combination of

and other equipment attached to the

A diverter staclt is a BOP stack that includes an annular

13

preventer, with a ~ent line beneath. A valve ~J installed in the vent

line so that the valve is open whenever the annular preventer is

closed, thus avoiding a complete shut off (CSO), and diverting the

flow of fluids away from the rig and personnel.

A full BQP stack is an array of preventers, spools, valves,

and other equipment attached to the wellhead such that complete shut

off (CSO) is possible under all conditions.

2 • Functions

The main function of the BOP equipment is to safely control the

flow of fluids at the surface, either by diversion or by complete shut

off. The equipment must be adequate to handle a range of fluid types,

pressures, and temperatures, and to accommodate different drilling

situations such as active drilling and tripping, or while the drill

string is out of the hole. The requirements of the BOP stack are to:

a. Close the top of the wellbore to prevent the release of

fluids, or, to safely divert the fluids away from the rig and

personnel.

b. Allow safe, controlled release of shut in, pressured fluids

through the choke lines and manifold.

c. Allow pumping of fluids (usually mud or water) into the

wellbore through kill lines.

d. Allow vertical movement of the drill pipe without release of

fluids.

Selection of BOP stacks and equipment should be made jointly by

an experienced geothermal drilling engineer and drilling supervisor.

It is preferable to employ a supervisor that is experienced in Hawaii

geothermal drilling experiences and conditions.

THE BOP AHCHOR

Complete shut off capability with a BOP stack requires the

existence of a BOP anchor. Three key factors are required for a sound

BOP anchor:

BOPI'UoCSIUQDD/BD'/WU)f11U'c.b 30, 199J 14

1. A mechanically sound, continuous stee~ casing of reasonable length, which probably will be 1000 feet or more, attached to the BOP stack.

2. A continuous and solid cement sheath in the annulus between the casing and the rock wall of the wellbore.

3. An impermeable rock interval around the wellbore and cement

sheath. The entire section of rock need not be impermeable but priority is given to placing and cementing the casing shoe in a

thick interval of competent and impermeable rock.

IMPACTS OF SUBSURFACE RISKS

Hawaii geothermal drilling has inherent risks due to the

unpredictability of subsurface conditions. Recognizing the risks and

being prepared for all possible conditions is the best form of blowout

prevention. Subsurface conditions that may pose the risk of a well

blowout are listed below:

1. The almost certain inability to obtain a sound BOP anchor with

surface casing in the weak, often broken, and vertically permeable

near surface volcanic rocks. As discussed in Section II, if a "kick"

occurs, these shallow rocks will not allow a cso at the wellhead without posing a significant risk of creating an externally vented

well casing blowout. (For discussion of externally vented blowouts, see Section VIII.)

2. The unexpected entry, while drilling, into a major fault and

fracture conduit which is charged with overpressured geothermal fluid&. Termination and control of such events requires the certainty

of a wellhead CSO with a full capacity BOP stack. 1

1 In the KERZ, sudden geothermal fluid flows, which subsequently registered 500 to 700 psi shut-in wellhead pressures, were encountered at depths shallower than expected~ in one case as shallow as 1,400 feet.

BOH'f'AaiiiiQUIJ'/BD',IIILD/Mrcb 30, 1193 15

The risk factors cited above reveal the importance of knowing

when a BOP anchor and consequent cso capacity are available to prevent

a blowout. If they are not available, diversion of uncontrolled flows

is judged to be the more prudent response. On these fundamental

considerations, two basic BOP stacks are recommended for Hawaii

geothermal wells which are drilled with rotary rigs for exploration,

production or injection purposes.

BOP STACK RECOMMENDATIONS

1. Diyerter Stack (Figure 1-Appendix Bl

A diverter consisting of an annular preventer and a vent line

should be installed on the surface casing. In Hawaii, this casing

is typically 20 inches in diameter and is cemented in the 800 -

1,100 foot depth range. Incompetent near surface volcanic rock

and the high risk of cementing failure will not provide an

adequate BOP anchor for the surface casing. CSO is not intended

with this equipment; diversion of fluids is deliberate to avoid

creating externally vented blowouts, and for personnel and rig

safety.

2. Full BOP Stack (figure 2-Appendix B

A full BOP stack should be installed on the intermediate casing.

In Hawaii, this casing is typically 13-3/8 inches in diameter,

and is cemented in the 2, 000 - 3, 500 foot depth range. This

deeper casing, cement sheath, and host rock serves as a BOP

anchor. The selection and arrangement of this stack allows for

the use of a full range of drilling fluids (mud, water, aerated

~luid, foam, air) and should be a geothermal industry premium

stack that is capable of confident, immediate CSO over the range

of temperatures and pressures anticipated. If a sufficient BOP

anchor is not obtained, this stack also has diverter capacity

because of the flow "T"jvent line, or banjo box/blooie line,

included in the stack.

16

The BOP stack arrangement shown in Figure 2 is one of several

combinations available. Another possible arrangement is to remove

the lowermost pipe ram shown in Figure 2 and install it above the

choke and kill lines, in tandem with the blind ram. A full BOP

stack should be maintained at all times while drilling in the

vicinity of the production zone.

ADDITIONAL RECOMMENDATIONS

1. Diyerter stack. The di verter stack should have the

following characteristics:

a. A minimum pressure rating of 2,000 psi for all

components.

b. Minimum vent line diameter of 12 inches.

c. A full opening valve on the vent line that opens

automatically when the annular preventer is

closed; QR a 150 psi rupture disk and a normally

open valve.

d. The vent line directed through a muffler.

e. H,S abatement capability connected to the vent

line.

2. Full BOP Stack. The Full BOP stack should have the

following characteristics:

a. A minimum pressure rating of 3,000 psi for all

components. A pressure rating of 5, ooo psi is

recommended when indicated by the risk analysis

of the well. For teaperature impacts on pressure

ratings, see Figure 3 Appendix B.

b. Lower spool outlets - 2 inch diameter for a kill

line and 4 inches for a choke line.

c.

d.

BCII'ftiC:U&~P/811'/WUJ/IIUCb lO, 1993

The pressure ratings for the kill and choke lines

the same as the stack.

All preventers should have high temperature rated

17

ram rubbers and packing ~-d ts.

BOP EQUIPMENT RECOMMENDATIONS

1. Kill Line. 2 inch diameter kill line from pumps to

spool, Two full opening valves and one check valve at the

spool. Fittings for an auxiliary pump connection; pressure

rating for the kill line the same as the stack. The kill

line is not to be used as a fill up line.

2. Choke Line and Choke Manifold. 4 inch choke line and

manifold; pressure rating the same as the stack. Two full

opening gate valves next to the spool; one of these valves

remotely operated.

3. Actuating system. The actuating system should have an

accumulator that can perform all of the following after its

power is shut off:

a. Close and open one ram preventer.

b. Close the annular preventer on the smallest drill

pipe used.

c. Open a hydraulic valve on the choke line, if used.

The actuating system is to be located at least 50 feet from

the well, with two control stations - one at the drillers

station on the rig and one at the actuating system location.

Valves shown may be hydraulically or manually operated, as

appropriate for the intended service. However, valves should

be operable from a remote hydraulic control, or by

mechanical extensions, if they are located where they are

not readily accessible during a well control incident.

4 I Other equipment I During drilling the following

miscellaneous BOP equipment is to be provided:

a I Upper and lower kelly cocks and a standpipe valve.

b. A full opening safety valve, to fit any pipe in

80PftACU6-.uiP,IDII/IILD,IIIareb JO, 1993 18

the hole. Kept on the ri~ floor.

c. An internal preventer, kept on the rig floor, with

fittings to adapt it to the safety valve.

d. Accurate pressure gauges on the stand pipe, choke

manifold, and other suitable places that may see

wellbore pressure.

e. All flow lines and valves rated for high

temperature service.

&OPII'l'KDIIQUIP ,IJIBif/lfUI/JI&rcb 30, 1993 19

V. E'V'UIPMENT TESTING AND IN$fECTION

In general, a visual inspection and an initial pressure test

should be made on all BOP equipment when it is installed, before

drilling out any casing plugs. The BOP stack (preventers and spools,

choke and kill lines, all valves and kelly cocks) should be tested in

the direction of blowout flow. In addition to the initial pressure and

operational test at time of installation, periodic operating tests

should be made.

Pressure tests should subject the BOP stack to a minimum of 125%

of the maximum predicted surface pressure. If the casing is tested

at the same time then the test should not be more than 80% of minimum

internal yield of the casing at the shoe. If a test plug is used, the

full working pressure of the BOP stack can be tested; a casing test

would be made separately. Testing of the actuating system should

include tests to determine that:

1) The accumulator is fully charged to its rated working

pressure;

2) The level of fluid is at the prescribed level for that

particular unit;

3) Every valve is in good operating condition;

4) The unit itself is located properly with respect to the

well;

5) The capacity of the accumulator is adequate to perform all

necessary functions including any kick control functions

such as hydraulic valves that are using the same unit for

energy;

6) The accumulator pumps function properly;

7) The power supply to the accumulator pump motor will not be

interrupted during normal operations;

8) There is an adequate independent backup system that is ready

to operate properly; and

SC&ZUIIW\Ba\~ 11, 1912 20

9) The con~rol manifold is at least s~ feet from the well and

a remote panel is located at the driller's station.

10) All control valves are operating easily and properly, have

unobstructed access and easily identifiable controls.

The sequence of events to test the BOP stack and all other valves

depends on the stack configuration, but it is important that all

equipment is tested, including the annular preventer, pipe rams, cso

rams, upper and lower kelly cocks, safety valves, internal preventers,

standpipe valve, kill line, choke manifold and choke control valve,

pressure gauges, and any other items that are installed as part of the

BOP equipment.

In addition to the testing of BOP equipment when it is first

installed, there should be frequent BOP testing and drills. The

closing system should be checked on each trip in or out of the hole

and BOP drills should be held at least once a week for each crew.

It is most important that every member of the crew be familiar with

all aspects of the operation of the BOP equipment, along with all of

the accessories and monitoring devices that aid in detection of a

kick. The main purpose of drills is to train the crew to detect a

kick and close the well in quickly. BOP drills should cover all

situations while drilling, tripping, and with the drill string out of

the hole.

... IUilW\,BB\IItD~ 11, 1992 21

VI . I) RILLING MONITORING PROCtDJJRES

INTRODUCTION

Operators commonly provide for some level of monitoring in the drilling of most geothermal wells. All types of monitoring procedures

will incur additional costs, which may limit the selection of specific procedures. However, most Operators determine the specific procedures

in the context of what is known and not known about the subsurface environment to be penetrated by the wellbore. This discussion of

monitoring will use the broad sense of the term, including mud logging.

Monitoring procedures may be defined as an array of continuous sensing actions which attempt to accurately indicate subsurface

conditions as the drill bit is advancing through the rock formation.

MONITORING RATIONALE

Geothermal wells drilled within the prospective, active volcanic rift zones of Hawaii, merit carefully planned and integrated

monitoring procedures. This view is supported by two primary concerns.

First, the subsurface geology, hydrology, temperatures and pressures

in the rock roof above the deep magma conduits, which create the rift zone, are only partially known. Only 14 deep geothermal bores (11

wells and three scientific observation holes) have provided hard,

factual subsurface data as of mid-1992. secondly, two geothermal

wells have demonstrated that fault or fracture conduits, charged with high pressure, high temperature fluids can extend upward to relatively

shallow depths from a deeper subsurface domain of >600°F temperatures. These near vertical and planar conduits present both blowout risks and

significant geothermal energy production potential. This recent

finding, proven by drilling, has major implications. Geothermal

drilling requires the evaluation and more effective utilization of

monitoring procedures as a supplemental strategy for blowout

prevention.

22

VITAL SECTORS

Monitoring focuses on three vital sectors during the drilling of

a geothermal well:

1. Drilling penetration rate and drill bit performance

measurements. The penetration rate, commonly measured and

recorded in feet per hour, indicates the mechanical progress

of drilling in the host rock. Weight on bit, rotational

speed and torque are additional measurements that are made

to better understand the variations of the drilling

penetration rate.

2. Drilling fluid circulation in the wellbore which clears the

newly made hole of drilled rock debris, cools and lubricates

the rotating bit, and drilling string. Importantly, the

density and hydrostatic pressure gradient of the drilling

fluid are commonly used to control the formation fluids and

pressures encountered.

3. Physical conditions and resource potential of the newly

penetrated rock formation. The array of information

gathered in this sector is commonly presented in a

continuous "mud log" graphic record over the entire interval

drilled.

The information products from the sectors discussed above have

important potential applications. Possible immediate improvements

might be indicated in drilling procedures, drilling fluid properties

or casing plan in the well itself. Enhancements in well design,

drilling programs and/or cost reductions can be determined for future

wells- The information provided by way of monitoring procedures, with

careful integration and evaluation, can make important contributions

to an Operator's blowout prevention strategy.

OPI'IMIZING BLOWOU'l' PREVENTION

23

Any effective'reduction in blowout risks ~s primarily contingent

upon accurate interpretation of monitoring data, and ultimately

depends on the decisions made based on this data. This must be

achieved by the Operator. Having made the risk analysis, written the

drilling plan and obtained the funding for the well, the Operator's

geologist and drilling engineer presumably would be the most qualified

persons to establish the method by which the selected monitoring

procedures would be used to contribute to a blowout prevention plan.

In prospective Hawaiian rift zones, the prudent Operator, making

careful use of monitoring information, can better identify the

potential for hot and overpressured fault and fracture conduits, and

can better prepare for penetration of such conduits and reduce impacts

of kicks and lost circulation. Alternatively, the Operator can make

the decision on whether or not to set casing, particularly if a long

open hole section is exposed above the interval of concern.

Critical data that may reveal the degree and/or immediacy of a

blowout risk are probably first observed by key personnel of the

drilling and mud logging contractors. Exercising personal control of

drill bit performance in making hole, drillers are the first to sense

change at the bottom of the wellbore. Additionally, drillers must

have an accurate, real time knowledge of the drilling fluid upflow in

the annulus between drill pipe and the wall of the open hole. Gain

or loss departures from 100% of the drilling fluid pumped down the

drill pipe and through the bit orifices are critical indicators that,

alone or with other corroborating information, signal a disruption of

a normal drilling mode.

The mud logger and a supporting multiple sensor system

continuously survey the changing rock features, formation fluids and

temperature variations reflected in the returning drilling fluid.

This work is both time critical and time short because it focuses

evaluation on the narrow window of freshly exposed hole behind the

continuously advancing drill bit. Accordingly, good quality,

competitive mud logging has become a highly automated, computer

assisted service with an impressive reliability. The mud logger is

the first to evaluate the formation gas and liquid entries, via the

SW-I'f<aiWG/WLD~ 11, 1992 24

returning drilliriy fluid, that may signal t"e penetration of high

temperature, high pressure conditions.

Operators of Hawaiian geothermal drilling projects need to assure

that a high level of cooperation in comprehending the norm and the

upset hole conditions are mutually practiced by their contracted

drillers and mud loggers. The Operator's drilling engineer and

geologist should establish and maintain active communications with

these key specialists throughout the drilling process. It is

essential that drillers and mud loggers have reliable, instantly

available electrical communication between their work stations if

monitoring procedures are

reduction of blowout risks.

eliminate a common problem:

to more effectively contribute to the

These simple procedures are intended to

too often a key piece of new information

is received, but is not properly read, understood or communicated.

Operators must lead their drillers .and loggers to consistent

cooperation in monitoring procedures as an important protection

against the loss of well control. Inadequate responses to new well

monitoring information must be minimized in Hawaiian geothermal

drilling.

DRILLING FLUIDS AliD GBOTHERIIAL WELL CORTROL

All authoritative publications on blowout prevention (which to

date exclusively address oil and gas drilling) stress the role of

drilling fluids in minimizing, if not precluding, entries of normal

or high pressured formation fluids into the wellbore during the active

drilling process. This is achieved by circulating a weighted mud or

salt water drilling fluid which creates an excess or overbalance of

internal hydrostatic pressure on every square inch of the open

wellbore. The normal hydrostatic pressure gradient for the formation

fluid& in Hawaii rift zones should approximate 433 psi per 1,000 feet

of vertical depth for fresh water and 442 psi per 1,000 feet for salt

water. This range of pressure gradients may prevail over much of the

KERZ in the deep geothermal zones; several geothermal wells were

drilled through 2,500 foot intervals of hot (600-700.F) prospective

rock interval by circulating fresh water as a wholly satisfactory

25

drilling fluid. ••ell control was maintain"-- confidently in these

operations and, subsequently, these fresh water drilled intervals

yielded proven geothermal fluids during flow tests following well

completion. It should be noted that the greater cooling capacity of

water, as compared with mud drilling fluids, played a positive role

in these achievements.

Cooling by the circulation of drilling fluid is an inherent

physical process in geothermal well drilling. Where accelerated or

optimized, the cooling process itself can be recognized as a well

control function. The efficient cooling of circulating drilling fluids

particularly will require an adequate surface cooling facility in the

loop. Mud cooling towers which allow the hot returning mud to fall in

a baffle system against a cool air draft are a standard equipment

option for geothermal drilling. It is important that mud cooling

towers be adequate for the heat load anticipated and that they be

carefully maintained and monitored during use to assure that cooling

is being effectively accomplished. Additionally, geothermal well

control in Hawaiian rift zones requires ready access to an ample

supply of cool water for wellbore circulation as a well control

option.

Both the specific KERZ drilling experience and the practice of

world wide geothermal drilling demonstrate the disinclination to drill

with heavily weighted muds or saline solutions as a preferred means

of well control. This follows from the expectation of fractures in

the prospective hot zones which have much higher permeability and

production potential than a bulk rock interval of some uniform primary

(commonly lower) permeability. Fractures present the immediate risk

of lost circulation and a possible well kick, particularly when

overpressured fracture fluids are released. The perceived benefits

of significantly weighted drilling fluids (significant overbalance -

where the hydrostatic head of the fluid column exceeds the formation

fluid pressure) usually is lost immediately in geothermal wells which

successfully penetrate fractures. The loss of drilling fluid from the

wellbore into formation fractures is accelerated in direct proportion

to the overbalance due to excessively weighted mud. If, as indicated

26

to date, blowout risks in Hawaiian rift <.-.ines are predominantly

fracture controlled and fracture specific, it does not appear that

excess weighting of drilling fluids will be a common means of blowout

risk reduction.

MONITORING INDICES FOR BLOWOUT PREVENTION

Monitoring procedures, taken as an aid to blowout risk reduction

in Hawaii drilling, can be focused on a group of five categories, as

discussed below. The sequence of the categories is believed to be in

order of importance when examined with the assumption that the sudden

encounter of high pressured geothermal fluids in fractures constitutes

the primary blowout hazard in these volcanic rift zones.

A. DRILLING WITH MUD OR WATER CIRCULATION

1. Bottom hole temperature variation. The blowout hazards

in Hawaiian rift zones have a strong correlation with

high subsurface temperatures. A working impression

that 600°F and higher temperatures were present below

4, 000-foot depths under the Kapoho-state geothermal

leaseholds, and at greater depths uprift in KERZ, may

have prevailed before the KS-7 and 8 blowout events.

These wells respectively vented 500°F fluids from below

1,400 feet and 620°F from below 3,476 feet in

uncontrolled flows at the wellheads. Bottom hole

temperatures (BHT) cannot be measured in the active

drilling process because of the cooling induced by the

drilling fluid circulating around the rotating bit.

Alternatively, the exit temperature of the drilling

fluid vented at the wellhead annulus is continuously

recorded. The sharper excursions of increasing

temperature with depth are the features of interest in

the automated plot of exit temperature. The mud logger

can immediately read such temperature increases in the

context of the complete temperature profile (surface

~I~/WUI~ 11, 1992 27

to ...:urrent depth) and detect po_.,;ible correlations with

events on other indices. A supplemental

temperature: depth record is frequently obtained by

measuring with maximum reading thermometers inside the

drill pipe at a stop immediately above the drill bit

for some consistent time interval (say 20 minutes) at

some regular frequency the Operator finds appropriate.

This independent survey does not obtain equilibrated

BHTs; however, it provides a more discriminate

reference for the exit temperature plot. With respect

to blowout risk reduction, neither the existing BHT

value or any specific high temperature value has

primary importance. Rather, it is sharply rising

temperatures, coincident with other dynamic events

observed in an integrated monitoring procedure, that

are to be taken as a caution or evidence that a blowout

threshold is being approached.

2. Drilling penetration rate. Variations in drilling rate

commonly reflect rock conditions encountered by the

drill bit, provided such factors such as weight on bit,

rotational speed, and torque are uniform, or their

coincident variations are understood. Increases in

drilling rate (a drilling break) can indicate a porous

and permeable interval containing formation fluids;

fractured rock can cause sudden erratic perturbations

in all these mechanical drilling indices. Major

fractures in the KERZ can allow the drilling assembly

to free fall into open voids. The consequences of such

a fracture encounter are frequently immediate.

competent drillers will quickly determine the status

of their drilling fluid return flow in appraising the

situation and apply an appropriate response, if

required. Increases in drilling rates coincident with

the penetration of high pressure zones are described

in some blowout prevention treatises on the conclusion

that bits drill faster in underbalanced mud weights

........ li'tMDG/WLD~ 11, 1993 28

a~~roaching high pressured ~ones. It should be

determined by studies of well logs if KERZ drilling

experience, past or future, suggests any basis for

reading drilling rate variations as an indicator of

penetration of high pressure zones. One prudent option

in drilling fractured, high temperature intervals,

especially with initial formation fluid entries

identified in the return drilling fluid, is to

deliberately reduce penetration rate or briefly hold

in a full circulation mode to confirm drilling fluid

system status and to observe more of the impact of the

formation fluids encountered.

3. Drilling fluid circulation. Accurate knowledge of the

drilling fluid condition, particularly its weight in

pounds per gallon, and its functioning in the wellbore,

is critical to drilling with effective well control.

Any departure (gain or loss) from a 100% return of the

pumped circulating volume, delivered through the drill

pipe to the drill bit, needs to be promptly evaluated

as to magnitude and meaning. Continuous measurement

and recording of the drilling fluid gain, loss, or 100%

return is made in specific tanks (mud pits) included

in the fluid circulation loop. Either gain or loss of

drilling fluid must be taken as a warning of increasing

blowout risk. A gain is a reliable indicator of

formation fluid entry into the wellbore (kick). If

well flow is indicated or suspected following a gain,

drilling should be halted, the kelly pulled above the

rotary table, the mud pump shut down and the exit flow

line visually examined for possible flow. If the well

is flowing in these circumstances, the annular

preventer should be closed to identify pressure

buildups on both annulus and drill pipe. These

pressures, when stable, would identify the increases

in mud weight and wellbore hydrostatic pressure

necessary to terminate the formation fluid inflow. An

m:Wl~/11t.D~ 11, 1992 29

ev~Luation of the option of Ci ~ulating cool water in

the wellbore should be made if the kick is associated

with a temperature increase.

Partial or complete loss of drilling fluid returns is

the more common problem consequent to fracture

penetration. Complete loss of circulation, followed by

a falling fluid level in the wellbore annulus is a most

likely trigger for a blowout event. Drilling must be

halted, the drilling string pulled up Conly to the

first drill pipe tool iointl and the preventer closed

until the situation is evaluated and a response

determined.

4. Formation fluid entry. All geothermal fluid bearing

zones, both high and normally pressured, will be first

identified by the drill bit penetration, with a

subsequent charge of gases into the drilling fluid

upflow in the annulus. Mud logging systems will

automatically measure and record carbon dioxide,

hydrogen sulfide, methane and ethanol in parts per

million on a log scale whenever the drilling fluid is

being circulated. Although this information has a time

lag compared to the immediacy of a drilling break, it

is the most positive specific indicator that geothermal

fluids have been encountered. Gas-cut drilling fluid

returns, coupled with temperature increases, are a

clear warning that a high pressure zone of considerable

flow potential may be at hand. With additional

penetration, geothermal formation liquid fractions may

cause detectable salinity increases in the return

drilling fluid. Salinity determinations are not an

automated monitoring procedure, but are optionally

performed by the mud logger in evaluating fluid entry

events.

5. Secondary mineralization. Geothermal fluid bearing

faults, fractures and zones are predominantly enclosed

30

in a sheath or seal of secondaLy minerals. secondary minerals are continuously identified and recorded in

geothermal mud logging with the intent of discerning, in correlation with the wellbore temperature profile,

the most prospective intervals for fluid production. Logic would suggest that the larger hot fluid conduits,

which present both significant production potential and blowout risk, would likely have a thicker sheath of

secondary minerals. The extent to which this prevails in the Hawaiian rift zones and to which it may be a

particular precursor to high pressured geothermal fluids in fractures is not well known. Natural

variations in the secondary mineralization process, consequent to a new fracture opening for geothermal

fluid conduction, may be extreme; any secondary mineral sheath could presage a fluid filled fracture or a

fracture that is completely sealed by mineralization, particularly in the active faulting and fracturing of

the KERZ. Whatever may be the present view of this

apparent index, it appears to merit careful evaluation

within the concept of integrated monitoring as a

logical part of blowout prevention strategy.

B. DRILLING WITH AIR, AERATED LIQUIDS OR FOAM

These drilling fluids are utilized in the underbalanced drilling option, which is often employed in geothermal drilling,

particularly in known vapor dominated reservoirs. Air or aerated liquids drilling, signified by substantial additional equipment

and service requirements, (air compressors, rotating head, banjo box, blooie line, drilling muffler and H,S abatement backup) has

been employed on a geothermal exploration well in the KERZ.

Expectedly, air and aerated fluids drilling will be used and

further evaluated in the Hawaii environment. Air drilling eases the driller's concern with circulated fluid controls on formation

fluids; the formation fluids, with relatively unrestrained entry

to the annulus, are transported to the surface and through the

drilling muffler for chemical and noise abatement before release

31

to the atmosphere. The mud logger's int~rpretation of rock and mineral cuttings is degraded somewhat by the much reduced rock

particle size produced by air drilling. Otherwise the drilling monitoring procedures discussed above will apply for the same objective of blowout risk reduction.

SUMMARY

An optimal use of monitored drilling information in a blowout

prevention strategy requires the informed participation and responses of competent drillers and mud loggers. A logical assignment of

primary responsibility for the categories discussed above would be:


Logger temperature variations secondary mineralization formation fluid entries

Computer based graphic data presentations are increasingly used at the driller's stations to quickly provide both present status and

cumulative record on the drilling and fluid circulation processes. Both caution and alarm thresholds can be set on the incoming real time

information streams to alert drillers and supervisors to upset

conditions. such systems offer an advantage to the blowout prevention

objectives necessary to Hawaiian geothermal drilling, provided that competence in their use is created by diligent training.

The mud logging services contracted to most of the geothermal drilling operations in the KERZ have been state of the art quality at

the time of every execution. Very substantial improvements in reliable automation have been made since the mid-1980s. In summary, Operators

have adequate monitoring procedures at hand to reduce blowout risks. The driller's main focus is on immediate deviations from the

contr~lled drilling process, and the mud logger's main focus is on subsurface physical consequences of borehole advancement. Blowouts

are commonly preceded by multiple warning signs of increasing risks.

The Operator's drilling engineers and geologists, with the close

cooperation of drillers and mud loggers, can more accurately recognize

such risks and more quickly act to control or reduce them with the

~/lftD~ 11, li92 32

drilling monitorH•.,I procedures discussed hen ..

A final comment should be made on drilling fluid monitoring

requirements while tripping the drilling string. Frequently in

geothermal well drilling with mud and water, the hydrostatic pressure

of the fluid has only a moderate overbalance on the formation fluids.

This is further reduced with the cessation of circulation immediately

before pulling the drill string, as for a new bit. In hot,

prospective rock zones, the large diameter drilling assembly moving

up hole can swab, or pull, formation fluids into the borehole, by

further reducing the hydrostatic pressure below the bit. The greatest

danger of swabbing occurs when pulling the first few stands of drill

pipe (drilling assembly just pulling off bottom). At this point, a

careful confirmation of the drilling fluid fill-up volume, required

to hold the fluid level at the wellhead, is essential. If the well

fill-up volume is less than the volume of drill pipe pulled, swabbing

should be inferred, the bit returned to the bottom and the hole

recirculated to clear the formation fluids from the well. In summary,

swabbing is a mechanism that can and has caused blowouts. A slower

pulling of the initial stands and the fill-up check are the defensive

procedures to use.

~ncaiWC;fiiLD/')I09'albe' 11, 1992 33

VII. KICK CONTROL

INTRODUCTION

In drilling terms, a 'kick' is often the first indication at the wellhead that there are problems with control of formation pressure.

A kick is defined as the entry of formation fluids (water, steam, or gasses) into the well, which occurs because the hydrostatic pressure

exerted by the drilling fluids column has fallen below the pressure of the formation fluids. If prompt action is not taken to control the

kick and to correct the pressure underbalance, a blowout may follow. Some of the main causes of these pressure imbalances are:

1. Insufficient drilling mud weight. 2; Failure to properly fill the hole with fluids during trips.

3. Swabbing when pulling pipe. If the drill string is pulled

from the hole too rapid! y, the pressure may be reduced,

allowing formation fluids into the bore. 4. Lost circulation.

KICK IDENTIFICATION

There are a number of warning signs that indicate that a kick is

occurring or that it may soon occur. Some of these signs, which may

not be present in all situations, are:

1. An increase in the returning drilling fluids flow rate,

while pumping at a constant rate. 2. An increase in mud pit volume.

3. A continuing flow of fluids from the well when the pumps

are shut down. 4. Hole fill up on trips is less than the calculated amount.

5. A pump pressure change and a pump stroke increase while

drilling.

6. An increase in drill string weight.

7. A drilling break. (A sudden increase in penetration rate)

BOPKlCU/WLD/BIII~ 11, 1992 34

8. Gas cut mud or reduced mud weight ~~ the flow line.

9. Lost circulation.

10. A rapid increase in flow line temperature.

Each of the above warning signs individually does not positively

identify a kick. However, they do warn of a potential for a kick.

Every driller and derrickman should be expert in recognizing these

indicators and all crew members should be trained to take action. In

geothermal drilling, in addition to being alert to the above warning

signs, it is of prime importance to: 1) monitor drilling fluid

temperatures in and out while drilling; 2) maintain a frequent and

close analysis of the formation cuttings for a change in

mineralization; and 3) exert caution when drilling through formations

where lost circulation zones are expected. Difficulties or abnormal

conditions with any of these indications or procedures can also

indicate a potential kick.

SHUT IN PROCEDURES

The severity of a kick depends on the volume and pressure of the

formation fluid that is allowed to enter the hole. For this reason,

it is desirable to shut the well in as quickly as possible. When one

or more warning signs of a kick are observed, procedures should be

started to shut in the well. If there is doubt as to whether a kick

is occurring, shut in the well and check the pressures and other

indicators.

Specific shut in procedures when one or more kick warning signs

are observed:

1. WHILE DRILLING

a. Pick up kelly until a tool joint is above the table.

b. Shut down the mud pumps.

c. Close the annular preventer.

d. Notify the company supervisor.

e. Record the drill pipe and annular pressure build up.

2. WHILE TRIPPING


35

b. Inst-~.11 the full opening safety .alve.

c. Close the safety valve; close the annular preventer.


e. Make up the kelly; open the safety valve.

f. Record the drill pipe and annular pressure build up.

3. WHILE OUT OF THE HOLE

a. Close the well in immediately.

b. Record the pressure build up.

c. Notify the company supervisor.

d. Prepare for snubbing or stripping into the hole.

4. WHILE USING A DIVERTER



c. Open the diverter line valves.

d. Close the annular preventer.

e. Start pumping at a fast rate.


KICK KILL PROCEDURES

Several proven kick killing methods have been developed over the

years, based on the concept of constant bottom hole pressure. Two of

the most common methods are know as the "drillers" method and the

"wait and weight" method. Rig personnel should be familiar with, and

trained in, these procedures.

Selection of the method to be used in a particular kick situation

should be made by an experienced, qualified drilling supervisor. The

actual method used will depend on knowledgeable considerations of

surface pressure, type of influx, the time required to execute the

procedure, complexity of the procedure, down hole stresses that may

be present or introduced, and available equipment.

All of the above are suggested procedures, to be modified by a

knowledgeable drilling supervisor to suit the particular conditions

existing at the time of the kick.

36

VIII. BLOWOUT CLASSIFICAi)ON

INTRODUCTION

Any uncontrolled flow of steam, brine or other well fluids

constitutes a blowout. A discharge of these fluids at the surface is

usually taken as the basic identifier of a blowout. However, surface

discharge, if it occurs, is only the symptom or consequence of the

fundamental upset condition that results in a blowout.

In the context of Hawaii geothermal activities, a broader, yet

more precise, definition of a blowout: can be stated as a "loss of

control of the natural pressures and fluids encountered in the

drilling of a geothermal well."

There are several types of geothermal well blowouts, varying in

their severity and in the techniques needed to control them. The

impacts on surface and subsurface environments, resource waste, and

public perceptions of these incidents demand that Operators and

regulators minimize the risks of blowouts. The types of blowouts that

may be experienced in Hawaii include the following:

A. SURFACE BLOWOUTS

1. Casing contained. An uncontrolled flow of steam or other

fluids through the casing and wellhead will result in the

escape of fluids to the atmosphere. This may result in

unabated gas emissions and noise disruptive to the

surrounding community and the surface environment

surrounding the well. This type of blowout may cause minor

to major damage to the wellhead, BOP equipment stack, or

drilling rig. Response to the blowout will depend on the

specific situation. Efforts will focus on wellhead repairs,

control of fluid discharge, and access to the area for

specific procedures. The availability of drilling fluid

supplies (including water), and the condition of the

37

drillin string and casing will key elements in an effective operation to regain well control.

2. Externally Vented. Moderate case low-to-moderate fluid venting

outside the casing or the cellar; the drilling rig, wellhead and BOP are generally undamaged and operable. May or may not be disturbing to surrounding community.

Responses may include grouting at the leak to terminate surface flow.

• Worst case - venting volume and/or velocity leads to rig collapse and/or cratering around or near the

wellhead. Response will probably require a relief well if the hole doesn't bridge or collapse on its own, thus terminating the flow.

B. UHDERGROUHD BLOWOUTS

Although this class of blowout lacks any surface display, the event could escalate into a surface blowout if not recognized and

resolved at an early time.

~ High pressure fluid upflows, in the open hole, from a

deep zone to a shallower permeable zone (lower temperature

reservoir or groundwater) . Such events may range from serious degradation or destruction of the open hole, to

minor resource loss and conservation problems. Response is generally to subdue the flow with water, weighted muds, or cement plugs as required. Additional casing/liner probably will be required, or the well may be plugged with cement for

redrill or suspension.

l..... High pressure fluid upflows, in the open hole, from a deep zone to an escape by hydraulic fracturing at the

deepest casing shoe, where the formation (pressure) gradient is exceeded by higher fluid pressure from the deep zone.

Response as above in 1.

38

IX. SUPERVISION AND TRAINING

INTRODUCTION

The major cause of most blowouts is human error; either none of the crew or the Operator's advisors recognizes an existing well control problem, or steps to control the situation are not performed soon enough. Most blowouts are fully preventable by properly trained drilling personnel. Thus, proper training of the crew is as important to successful well control as is the proper selection and use of blowout prevention equipment, as discussed in the preceding sections.

The Hawaii conditions for geothermal drilling require that every Operator recognize its prime responsibilities to provide supervision

and training that is several levels above the industry average. Hawaii's geothermal drilling industry is still in a formative

stage. Because there is no pool of operators and drilling personnel thoroughly familiar with all potential problems in Hawaii's geothermal resource areas, there is a need for operators, drilling contractors and regulators to pay extraordinary attention to all elements of

training for their personnel. There must be a proper balance between practical, on-the-job-training, operational drills, and formal study

for a wide range of individual experience levels. In a few cases, drilling and monitoring crews will have worked together closely in

other geothermal areas, some of which may exhibit well control challenges similar to Hawaii's. In other instances, crews will be made

up of a mixture of individuals that have not worked as a team before, and may have a larger percentage of new workers, especially at lower skill levels in the drilling and pr~duction jobs.

An additional consideration in the Hawaii case is the known occurrences of relatively high levels of H,S gas in the geothermal resource. Proper well planning and equipment selection can mitigate many of the hazards of H,S drilling in the well control sense, but it

is necessary that all drilling crews have a clear understanding of the

dangers and rules that accompany drilling in known H,S zones.

~ta»tarl ....._. 11, 1192 39

SUPERVISORY EXPER- .>HCE

Although complete training for specific crews that will drill in

Hawaii's geothermal zones is of primary importance, the art of well

control is not learned from classroom training alone. Therefore,

experienced supervisory personnel are vi tal to the process of training

the drilling crews, as well as in lending their experiences to the

ongoing supervision of the drilling. Drilling plans submitted should

discuss the levels of experience of the drilling crews, supervisors,

consultants and managers, with comment on the methods to be taken to

ensure that such experienced persons will be directly involved while

drilling activities are underway in Hawaii.

DRILLING TEAM TRAINING AND DRILLS

The training of drilling teams, including supervisory, management

and operating personnel, in well control and blowout protection can

be discussed in three basic levels. Level one:training through formal

courses that are infrequently offered by industry and regulatory

organizations, often at a regional or national level; level two: the

training that an Operator conducts on a more or less formal, or

classroom, basis with its drilling supervisors, drilling crews, and

others who directly support its Hawaii drilling operations ; level

three: Operators must have a program of drills that ensure all

personnel actually have 'hands-on' experience with the installed

blowout prevention equipment.

A number of organizations conduct training and certification in

well control, mainly directed toward the petroleum drilling industry.

However, recent classes in the specifics of geothermal well control

have been held by a cooperative effort of the Geothermal Resources

Counc.i,l and the National Geothermal Association, with funding in part

by the Federal DepartBent of Energy. This course has been approved

by the Federal Minerals Management service for training and

certification in well control subjects, and is recommended for

supervisory and other drilling personnel, as an indication of the

level of specific well control training and experiences of these

BOP'l».DmmG/ID/Irl llcw.-bu 11, 1992 40

personnel assigne~ to Hawaii drilling tasks. rhere are no plans to hold these formal courses often, and most certainly not in concert with specific drilling schedules of individual projects. Therefore, each Operator and drilling contractor will need to supplement the experiences of their supervisory personnel with direct team training

pointed toward developing an integrated effort for Hawaiian projects.

Operators should outline the formal (classroom) training proposed

for drilling personnel, with specific references to 'kick' recognition and blowout prevention, including monitoring systems, equipment, and

drilling procedures. A number of study guides and references are available for these purposes; publications to be used should be listed

in drilling plans so that they can be reviewed by regulatory review

personnel. A list of specific references is not included in this

Manual because these publications may become obsolete by newer editions. Appendix c, References, contains documents and sources used

in preparing this Manual, and should be consulted for suitability to

each drilling plan.

In addition to classroom training and periodic updates as drill

crews may shift or the drilling may enter new phases, blowout

prevention drills should be conducted on a regular (but unannounced)

basis to provide further training, and to keep crews focussed on the

possibilities of well kicks, and blowouts. Crews should be familiar

with the equipment in use, and be able to properly and safely shut in

the well before a control problem becomes dangerous to personnel or

the well itself. These drills should be directed at well control and proper blowout prevention procedures in three basic situations - when

drilling ahead, when 'tripping out' of the well, and when the drill

pipe is out of the wellbore.

Other blowout prevention and general safety training - both

informal and on-the-job situations, should be outlined in the drilling

plan. Subjects covered should include new employee orientation,

visitor briefings and general safety training. Formal training

sessions, regular review training and blowout prevention drills held

should be noted in the daily reports of the drilling operation.

41

X POST COMPLETION BLOWOUT p'J(EYENTION

It is important to realize that blowout risks are not restricted

to the initial drilling and completion of a geothermal well. At a much

lower incidence rate, blowouts can occur at producing wells and at

shut-in idle wells. Wellhead equipment should be recognized as

vulnerable to natural surface conditions and vandalism. The capacity,

integrity, and security of geothermal wellhead equipment are all the

responsibility of a production engineering expertise which is not

within the scope of this Blowout Prevention Manual.

Two areas of subsurface risks to casing string integrity in

existing Hawaiian geothermal wells should be noted. The corrosion

potential of wellbore fluids, in both the production and shut-in

(static) modes should be identified. Baseline chemistry and casing

evaluation procedures should be established shortly after well

completion. The objectives here are to assure and prolong casing

integrity, and to preclude any blowout consequent to a casing failure

due to corrosion. Wells that have been tested or have produced high

temperature fluids, and then are shut-in for periods of time,

particularly require regular and accurate monitoring of casing

conditions. Temperature decreases imposed by the active Hawaiian

ground water regime can accelerate H,S corrosion in shallow casing

strings in idle wells. Finally, the risk of casing failure in rift

zone eruptions and earthquakes (shallow fault movements, ground

disruption or rotational failures) should be recognized.

Blowout prevention requirements during remedial work, redrills,

recompletions and abandonments, in all geothermal wells, must be

evaluated and provided for by the same process of consideration

required in every new geothermal well drilling permit proposal.

~/WUJ/]Ia"nnlbu' 11, liltll: 42

,,.~ ~,

XII BLOWOJJT PREYENTION IN SI.IMHOI.ES

INTRODUCTION

Deep drilling with slimhole (approximately 4-6 inch bit

diameters) technology and equipment has achieved major advances in the

mining industry in the last several decades. However, the mining

drilling environment does not present pressure control problems

comparable to those encountered in petroleum and geothermal drilling.

For this reason, well control practices in slimholes were poorly

understood until recently. This hindered an expanding use of the

technology. However, the technical and economic advantages of

slimholes have recently registered with several petroleum companies;

Amoco Production Company has particularly investigated the

requirements of well control and blowout prevention in slimhole

drilling.'

KEY ATTRIBUTES

Much smaller volumes of drilling fluids are circulated in

slimholes. Kicks of any volume are of more consequence, and immediate

detection of fluid entry, or lost circulation, is critical.

Quantitative electromagnetic flow meters are used to measure drilling

fluid entry and exit volumes at the wellhead. These flow meters are

reliable and accurate, measuring gains of one barrel or less as

compared to pit gains of 15 barrels or more as frequent kick events

in the standard drilling mode. Unfortunately, the much greater size

of this type of meter required for standard diameter wellbores make

them cost prohibitive. Another feature of importance is the high

annular pressure loss (APL) incurred by drilling fluid circulation in

'Well Control Methods and Practices in small-Diaaeter Wellbores; D. J. Bode, et al Amoco Production co., October 1989. (Available from the Society of Petroleum Engineers, P. o. Box 833836, Richardson, Texas 75083-3836; Telephone 214-669-3377.)

43

slimholes. The hig,i.er rotary speeds (RPM) usea in slimholes also adds,

with the APL, a substantial increase (overbalance) above the

hydrostatic pressure of the drilling fluid on the borehole while

actively drilling or coring. This physical phenomena relates to the

very small annuli between drill tubulars and the rock wall. The high

APL can be used advantageously to effect a dynamic kill and control

of formation fluid entry below 2, 500-foot depths in slimhole by

accelerating the pumping rate to maximum levels in circulating out the

intruding fluids. In summary, blowout prevention in slimholes requires

special training, precision flowmeters, real time data presentation

and dynamic kill proficiency. It is likely that additional slimhole

drilling will be considered in Hawaii geothermal exploration and

development; Operators should carefully evaluate the Amoco paper

referenced when developing plans for these boreholes.

44


APPENDIX A

MANUAL REVIEW AND REVISIONS

APPENDIX A-

MANUAL REVIEW AND REVISION

Geothermal drilling experience in Hawaii, as of mid 1992, has

been quite limited. Only 14 deep geothermal boreholes had been drilled, and these were located on only one prospective feature, the

KERZ. Reasonable increases in geothermal drilling in the KERZ, and perhaps other areas, can be anticipated. New operational and

regulatory experiences should accumulate in the next few years. This Blowout Prevention Manual can best be accepted as a first

edition. Ideally, it should serve as a working reference for operators and regulators in a cooperative approach to the achievement of blowout

risk reduction. It is recommended that this Manual be reviewed and revised within

5 years of its date of issue by DLNR. such a time interval seems ample for the collection of new operating information and for a reasonable

application of the blowout prevention procedures recommended in the Manual. Frequent and informed discussion of blowout prevention

procedures between operators and regulators could prove to be one of

the most important consequences of the use of this Manual.

APPENDIX A-1


APPENDIX 8

ILLUSTRATIONS

'·

HAWAII GEOTHERMAL DIVERTER STACK

Fi9ure I.

A 2M ANNULAR PREVENTER

FLOW TEE or BANJO BOX

API ARRANGEMENT SA

2000 PSI

s

12"

HAWAII GEOTHERMAL FULL BOP STACK

Figure 2.

ROTATING HEAD

G I When usinll air

-installed on top of ANNULAR PREVENTER

RAM PREVENTER

RAM PREVENTER


CHECK VALVE

KILL 2" .C~JXID

API ARRANGEMENT RSRS RRA

MIN. 3000 PSI

A

R

R

s

R

R

ANNULAR PREVENTER

Remotely operated -VALVE

VENT/BLOOIE 12"

BLIND RAM

Remotely operated VALVE

CHOKE 4"

PIPE RAM

FIGURE 3

In Hawaii, where wellhead temperatures in excess of 600"F may

occur, Operators must consider the pressure derating of steel due to elevated temperatures when selecting wellhead equipment. The table

below, from the Aaerican Petroleum Institute (API) Specification 6A, provides the recommended working temperatures for steel at high

temperatures; this table goes only to 650"F.

In addition to the steel in wellhead equipment, the temperatures

found in Hawaii far exceed the temperature ratings of elastomers

found in most BOP equipment. Operators often use all steel rams in

ram type preventers for a more effective seal. The API recognizes temperature ratings of elastomers up to. 250"F, but some manufacturers

can now produce elastomers that are rated to 420"F.

APPENDIX B, FIG 3 -1

RECOMMENDED WORKING PR'ESSURES AT ELEVATED TEMPERATURES

E.1 Pressure-Temperature Derating. The maximum working pressure ratings given in this section are applicable to steel parts of the wellhead shell or pressure containing structure, such as bodies, bonnets, covers, end flanges, metallic ring gaskets, welding ends, bolts, and nuts for metal temperatures between 20F and 650F ( -29 and 343 •q. These ratings do not apply to any non-metallic resilient sealing materials or plastic sealing materials, as covered in Par. 1.4.4.

(-~2

Maximum Working

Pressure, psi (Bar)

TABLE E.1 PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS

(See Pu. U<l (I BAJ. • 100 t:PI)

(Sec Porewonl fOI" 8 Kp'n.ec. of Ullill)

I 2 3 4

Temperature, F t!b

-20 '"""' Ill l~ll JOO Uill "" Ulll "" (lg!l

2000 ill!2l 1955 {134.1} 1905 03l4l 1860 illYl

3000 = 2930 = 2880 = 2785 = 5ooo·UW! 4980 l.lli.ll. 4765 = 4645 =

5

"" !ml.

1810 ill!1l

2715 = 4525 LlllJil.

• Does •ot apply to 5000 pli 6BX cou.ectiou

Maximlfm Working

Pressure, psi (Bar)

TABLE E.1-Continued PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS

6

500 atm.

1735 llWl

2605 t!ZW

4340 !299.21

7

(Sec Par. 1.2.4)

(I BAR=- 100 II:PI.)

8

Temperature, F ('C)

550 WI!

1635 ii.Wl

2455 J.a2Jl

1540 ~ 2310 = 3850 !215.>1

9

650 lJ!.ll

1430 lWl

2145 = 3575 !:!A6.>l

APPENDIX B, FIG 3 -2


APPENDIX C

REFERENCES

APPENDIX C

REFERENCES

Adams, N., Well Control Problems and Solutions, Petroleum Publishing Company, 1980.

An Applicant Guide to State Permits and Approvals for Land and Water Use Development, Department of Planning and Economic Development, State of Hawaii/Coastal Zone Management, 1986.

API Recommended Practices For Safe Drimn~ of Wells Containjn~ H.S - RP49, The American Petroleum Institute, 1974.

Blowout Prevention EQuipment Systems for Dril!jn~ Wells - RP 53, 2nd Ed The American Petroleum Institute, 1984.

Bode, D. J., Noffke, R. B., and H. V. Nickens, Amoco Production Company, "Well Control Methods and Practices in Small-Diameter Wellbores", Society of Petroleum Engineers, October 1989.

Diener, D., Introduction to Well Control, Petroleum Extension Service, University of Texas at Austin, 1981.

Goins, W. C., Blowout Prevention Practical Dril!jn~ Technolo&)' - volume 1, Gulf Publishing Company

Hallmark and Wygle, Oil and Gas Blowout Prevention in California - Manual #M07, 2nd Edition, California Division of Oil and Gas, 1978.

Hills, A, Oyerview of the Status Development Approach and Financial Feasibi1ity, Department of Business and Economic Development, State of Hawaii, 1988.

Planning for Drimog in U.S Zones - An Outline of Safety and Health PrOCedures, Petroleum Extension Service, University of Texas at Austin, 1978.

Rowley, J. "Geothermal Standards .. A Decade of Leadership Continues" Geothermal Resources Council Bulletin, December 1991.

Geothermal Re&Jllations and Rules of Practice & Procedure. State of Nevada.

Rules for Geothermal and Cable System Development P!annin~. Title 13 -Administrative Rules, Department of Land and Natural Resources, Sub-Title 7. Water and Land Development, Chapter 185. State of Hawaii.

BOPUPBI.BNCBS-APPENEC/I.AP/Nona~Mr II, 1992 Appendix C-1

Rules on Leasin& ana" brimne of Geothermal Resources, Iitle 13 - Administrative Rules, Department of Land and Natural Resources, Sub-Title 7. Water and Land Development, Chapter 183. State of Hawaii

State Wjde Geothermal Re~latioos. California Administrative Code -Title 14, Natural Resources; Chapter 4, Sub-Chapter 4 - State of California.

Sumida, Gerald A, Alternative Approaches to the Le&al Institutional and Financial ASllects of Deyelopin& an Inter-Island Electrical Trapsmjs.sjon Cable System, Carlsmith, Wichman, Case, Mukai and Ishiki and First Interstate Cogeneration Capital Associates for the Department of Planning and Economic Development, State of Hawaii, April 1986.

Thomas, Richard, Whiting, R., Moore, J., and Milner, D., lpdependept Technical Inyestjeation of the Pupa Geothermal venture Upplanped Steam Release, Jupe 12 and 13, 1991 Puna Hawaii, for the State of Hawaii/County of Hawaii, July 1991.

BOPRIIPKUNCBS-J.PPBMII:/L\P/~ 11, 1992 Appendix C-2


APPENDIX D

GLOSSARY

APPENDIX D

GLOSSARY

A

accumulator n: 1. on a drilling rig, the storage device for nitrogen-pressurized hydraulic fluid, which is used in closing the blowout preventers.

annular blowout preventer n: a large valve, usually installed above the ram preventers, that forms a seal in the annular space between the pipe or kelly and wellbore or, if no pipe is present, on the wellbore itself.

API ~: American Petroleum Institute

8

BHP ~: bottom hole pressure.

BHT ~: bottom hole temperature.

blowout n; A blowout is an uncontrolled flow of formation fluids or gas from a well bore into the atmosphere or into lower pressure subsurface zones. A blowout occurs when formation pressure exceeds the pressure applied by the column of drilling fluid.'

BOP equipment n: The entire array of equipment installed at the well to detect and control kicks and prevent blowouts. It includes the BOP stack, its actuating system, kill and choke lines, kelly cocks, safety valves and all other auxiliary equipment and monitoring devices.

bottoa hole temperature n: The temperature of the fluids at the bottom of the hole. While drilling, these temperatures may be measured by minimum reading temperature devices, which only record temperatures above a designed minimum, and may not provide an accurate bottom hole temperature. Bottom hole temperature readings should be recorded after a period of fluids circulation at a particular depth, in order to stabilize the reading.

blowout preventer n: the equipment installed at the wellhead to

1 Rotary Dr ill ing BLOWOUT PREVENTION Unit I II , Lesson 3 ; Petroleum Extension Service, The University of Texas at Austin, Austin Texas, in cooperation with the International Association of Drilling Contractors, Houston Texas. 1980; 97 pages.

BOPGLOSSAJlY/ItAPIN~Il. 1992 Appendix D-1

prevent or control the escape of high pressur,. formation fluids, either in the annular space between the casing and drill pipe or in an open hole (i.e., hole with no drill pipe) during drilling and completion operations. The blowout preventer is located beneath the rig at the surface. see annular blowout preventer and ram blowout preventer.

BOP ~= blowout preventer

BOP stack n: The array of preventers, spools, valves and all other equipment attached to the well head while drilling.

borehole n: the wellbore; the hole made by drilling or boring.

c cap rock n: 1. relatively impermeable rock overlying a geothermal reservoir that tends to prevent migration of formation fluids out of the reservoir.

casing n. steel pipe, cemented in the wellbore to protect it against external fluids and rock conditions, and to facilitate the reliable and safe production or injection of geothermal fluids.

cellar n: a pit in the ground to provide additional height between the rig floor and the wellhead, and to accommodate the installation of blowout preventers, rathole, mousehole, and so forth. It also collects drainage water and other fluids for subsequent disposal.

ceaenting n: the application of a liquid slurry of cement and water to various points inside or outside the casing.

coapetent rock n. (in wellbores) any rock that stands without support in the drilled wellbore can be described as competent. Beds of ash, or loose volcanic clastics, are vulnerable to failure in open wellbores, and are thus considered to be incompetent rock.

complete shut off n. a full closure and containment of wellbore fluids and pressure at the wellhead.

conductor n: 1. a short string of large-diameter casing used to keep the top of the wellbore open and to provide a means of conveying the up-flowing drilling fluid from the wellbore to the mud pit. 2. a boot.

cso ~= complete shut off.

D

diverter n: a system used to control well blowouts when drilling at relatively shallow depths by directing the flow away from the rig. The diverter is part of the BOP Stack that includes an annular preventer with a vent line beneath. A valve on the vent line is

BOPOLOSSAAY/IAJII~ll, 1992 Appendix D-2

installed so that it is opened whenever the aunular preventer is closed.

drill collar n: a heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem to provide a pendulous effect to the drill stem.

drilling fluid n: a circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface. While a mixture of clay, water, and other chemical additives is the most common drilling fluid, wells can also be drilled using air, gas, or water as the drilling fluid. Also called circulating fluid. See mud.

drilling spool n: a spacer used as part of the wellhead equipment. It provides room between various wellhead devices (as the blowout preventers) so that devices in the drill stem (as a tool joint) can be suspended in it.

drill pipe n: the heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe are coupled together by means of tool joints.

drill string n: the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit. Often, the term is loosely applied to include both drill pipe and drill collars. Compare drill stem.

F

flange n: a projecting rim or edge (as on pipe fittings and opening in pumps and vessels), usually drilled with holes to allow bolting to other flanged fittings.

formation pressure n: the force exerted by fluids in a formation, recorded in the hole at the level of the formation with the well shut in. Also called reservoir pressure or shut-in bottom-hole pressure. See reservoir pressure.

J

joint n: a single length of drill pipe or of drill collar, casing, or tubing, that has threaded connections at both ends. Several joints, screwed together, constitute a stand of pipe.

K

kelly n: the heavy steel member, four-or six-sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa.

BOPOLOSIAIY/ItAP/N«mmiiNI'Il, 1991 Appendix D-3

kelly cock n: a valve installed between the swivel and the kelly. When a high-pressure backflow begins inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose. See kelly.

kick n: an entry of water, gas, or other formation fluid into the wellbore. It occurs because the hydrostatic pressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation drilled. If prompt action is not taken to control the kick or kill the well, a blowout will occur.

kill line n: a high pressure line that connects the mud pump and the well and through which heavy drilling fluid can be pumped into the well to control a threatened blowout.

L

L.C. ~= lost circulation

log n: a systematic recording of data, as from the driller's log, mud log, electrical well log, or radioactivity log. Many different logs are run in wells to obtain various characteristics of downhole formations. v: to record data.

lost circulation n: the loss of quantities of any drilling fluid to a formation, usually in cavernous, fissured, or highly permeable beds, evidenced by the complete or partial failure of the fluid to return to the surface as it is being circulated in the hole. Lost circulation can lead to a kick, which, if not controlled, can lead to a blowout.

M

manifold n: an accessory system of piping to a main piping system (or another conductor) that serves to divide a flow into several parts, to combine several flows into one, or to reroute a flow to any one of several possible destinations.

mud n: the liquid circulated through the wellbore during rotary drilling and workover operations. In addition to its function of bringing cuttings to the surface, drilling mud cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressures, and prevent loss of fluids to the formation. Although it was originally a suspension of earth solids (especially clays)- in water, the mud used in modern drilling operations is a more complex, three-phase mixture of liquids, reactive solids, and inert solids. The liquid phase may be fresh water, and may contain one or more conditioners. See drilling fluid •

.ud logging n: the recording of information derived from examination and analysis of formation cuttings suspended in the mud or drilling fluid, and circulated out of the hole. A portion of

BOPOLOIS.UY/RAP/~11, 1992 Appendix D-4

JQI-{N WAIHEE GQy,_::,-1NOF1 OF HAWAII



Mr. Ralph A. Patterson President R.A. Patterson & Associates 1274 Kika Street Kailua, Hawali 96734

Dear Mr. Patterson:

P. 0. BOX 373


SEP -1 1993

Geothermal Blowout Prevention Manual


SOAF10 OF LAND AND NATUF1AL F1ESOUF1CES

DEPUTIES


AQUACULTURE DEVELOPMENT PROGF1AM

AQUATIC RESOURCES

CONSERVATION AND ENVIRONMENTAL AFFAIF1S

CONSERVATION ANO RESOURCES ENFORCEMENT


HISTORIC PRESERVATION


WATER AND LANO DEVELOPMENT

Thank you for your August 9, 1993 letter and overall cooperation in preparing the Geothermal Blowout Prevention Manual.

Attached is a list of corrections to be made along with a marked-up copy for reference. A few context changes were necessary in order to provide accurate information and promote flexibility in the manual.

Should you have any questions on these r•u .. ,rs, please contact Mr. Gordon Akita of the Flood Control and Mineral Resource Branc at 5 7-0227.

U TAGOMORI r

JF:lc

En c.

,_,. ··'

Note:

CORRECTIONS FOR FINAL HAWAII BLOWOUT PREVENTION MANU!\L

Please see mark-up copy of the Manual for a referettce to the requested changes.

Text to be deleted is in [brackets]

Text to be added is underlined

Please make the following corrections:

1. Page after cover sheet, listing BLNR members and government officials: Misspelled KEPPELER.

2. Acknowledgement Page, bottom of first paragraph: Misspelled Tagomori.

3. Preface Page, middle of third paragraph: Delete [and], add an; Misspelled State.

4. Page 5, second paragraph: Please write as:

Primary features such as lava tubes, irreaular layers of ash and rubble contibute to very high horizontal permeabilitY..L whereas secondary features such as fractures contibute to very high vertical permeability; both features can pose a problem with loss of drilling fluid circulation and low rock strengths. These features seem to diminish downward, but appear to extend to depths of about 2000 feet.

5. Page 10, third paragraph, line 6: Delete [Commonly] from the beginning of the sentence; add commonly to line 7.

Example: The deliberate actions to optomize safety in geothermal drilling commonly will be specified or reflected in four distinct sections of the drilling plan, as follows:

6. Page 15, second paragraph, line 5: add while the drill string is.

Example: situations such as active drilling and tripping, or while the drill string is out of the hole.

7. Page 17, last line: Delete [Another possible arrangement might omit (continued on page 18) the ram preventer shown below the choke and fill line valves, saving the height of this valve. This would remove an important safety back-up in the event that the small valves fail or need repair; without this ram preventer there would be no last resort to preventing a

1

blowout in this area of the stack.]; add:

Another possible arrangement is to remove the lowermoJ3_t.~0P~ ram shown in Figure 2 and install it above the choke f!Jl~_ki.L!o lines, in tandem with the blind ram. A full BOP stack should be maintained at all times while drilling in the vicini_"ty··-;;f the production zone.

8. Page 24, bottom paragraph, line 6: add way.

Example: The imformation provided by way of monitoring procedures, with careful integration and evaluation, can make iportant contributions to an Opera tor's prevention strategy.

9. Page 27, last paragrpah, line 11: delete space to the left of the word "where".

10. Page 29, first paragraph, line 2· delete spaces after ttevents", "on", "other 11

, and before and after ''A''.

11. Page 32, bottom of page: underline Driller and Logger and format as follows:


Logger temperature variations secondary mineralizatio11 formation fluid entries

12. Page 45, last paragraph, line 7: Delete space in middle of paragraph.

13. Appendix A-1, Manual Review and Revision: delete the last paragraph.

14. Appendix C-1, References:

15.

References 3 and 10: change superscripted 2 in 112

8 to subscript. Example: H2S

Reference 12: delete [Geothermal] at the end of the first line; add Geothermal at the beginning of the reference.

Example: Geothermal Regulations and Rules of Practice &

Procedure, State of Nevada.

Appendix C-2, line 2 ''Sumida,Gerald, A.": delete

2

of reference [and]; add an.

beginning with

Example: Sumida, Gerald A., Alternative Approaches to the Legal, Institutional and Financial Aspects of Developing an Inter-Island Electrical Transmission Cable System.

16. Appendix D-2, Glossary:

First paragraph: add a period (.) after ''surface''.

Definition of casing: add or injection; delete [from the well] :

Example: casing n. steel pipe, cemented in the wellbore to protect it against external fluids and rock conditions, and to facilitate the reliable and safe production or injection of geothermal fluids.

Delete second definition of casing.

17. Appendix D-5, Definition of pipe ram: delete [and] and ram.

Example: See ram and ram blowout preventer.

3

add ram

R A. PATTERSON& ASSQ('TATES 1274 Kika Street Ka~lua, Hawaii 96734-452 (808) 262-5651. (808) 262-5350 (FAX)

September 20, 1993

Mr. Manabu Tagomori Department of Land & Natural Resources Division of Water and Land Development P. o. Box 373 Honolulu, HI 96809

Dear Mr. Tagomori;



We have made the changes and corrections requested in your letter of September 7 , 19 3 3. However, we remain concerned that the DLNRdesired wording describing the optional BOP stack configuration, (Section IV, page 17) would create a hazardous situation in the event of another failure of the wing valves (similar to that which occurred at the KS-1 well in October 1982). If the wing valves are below the ram preventer, an important safety back-up would be missing in the event that the small valves fail or need repair; there would be no last resort to preventing a blowout in this area of the stack.



enclosures cc: RCUH (letter only) bee: G. Akita, J. Flores

Sincerely,

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Ralph A. Patterson President R. A. Patterson & Associates 1274 Kika Street Kailua, HI 96734

Dear Mr. Patterson:

P. 0. BOX 373


July 27, 1993

Geothermal Blowout Prevention Manual and Drilling Guide

KEITH W. AHUE, Chairperson BOARD OF LAND AND NATURAL RESOURCES

DEPUTIES






LAND MANAGEMENT STATE PARKS WATER ANO LANO DEVELOPMENT

Thank you for the two bound copies and the original unbound copy of your "Hawaii Geothermal Blowout Prevention Manual". We will review the manual and provide you with our comments prior to printing and release to the public.

Submittal of two complete copies of the draft "Hawaii Geothermal Drilling Guide" is due on July 30, 1993. The final version of the drilling guide which is due on August 6, 1993, should include two bound copies and one original unbound copy. Also, copies of the Blowout Prevention Manual and Drilling Guide on disk in Wordperfect format should be submitted along with the final drilling guide.

Please note that according to the March 15, 1992 Agreement, you will be expected to present the Blowout Prevention Manual and Drilling Guide to our staff and to the Geotechnical Advisory Committee as your final tasks. The dates of these presentations will be scheduled after the submittal of the final Hawaii Geothermal Drilling Guide.

Should you have any questions on these matters, please contact Mr. Gordon Akita at 587-0227.

Sl cerely, ~-~

JF:ln

,IQHN WAIHEE

GOVHINOR OF H.O.WAII

Mr. Paul Stroud c/o Resource Group P.O. Box 1483



P. 0. AOX 373


AUG -5 1993

Healdsburg, California 95448

Dear Mr. Stroud:

KEITH W. AHUE, Chalrper~on

DEPUTifS


AQUACULTURE DEVfLOPMENT

PROGRAM

AQUATIC RESOURCES

CONSERVATION AND

ENVIrlONMENffo.l MFA!nS CONS(IWAlll•N MW

RESOURCES FNFOACEMENT

CONVfYANC"fS

f(lflf~;Jf\Y ANIJ Wlllllll!

HISTOFliC" rfl[SUWA T ION



Thank you for your May 1993 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in frnalizing the document.

Should you have any questions regarding this matter, please contact Mr. Gordon Akita of the Flood Control and Mineral Resource Branch at (808) 587-0227.

JF:lc

JOHN WAIHEE

00\IHINOR OF HAWAII

Mr. Bill Rickard c/o Resource Group P.O. Box 1483

rt;:~ \·· STATE OF HAWAII


P. 0. BOX 373


AUG -5 1993

Healdsburg, California 95448

Dear Mr. Rickard:


flri,\IHl <H IIINI1 M"' "~''"''" "'

lJFI'U 11r S

JOHN p_ KFPPELER. II DONA L. H/\N/\IKF

AOUACULlllfiF rJFVLI OPMFtl I

PI10GRAM AQUATIC A!::SOURCFS

CONSERVAIION AND

ENVIRO~lMFNTAl MI'AifiS \.ONSERVIITI(\N Atl()

RfSOI!Rr;r:s FNI'lflr'IMfNI CONI/f)/IN( I.-,

ronrsrnY Mm WllllLIIr


LAND MANAG~MENT

STAlE PARKS

WATER AND lAND DEVELOPMENT

Thank you for your May 1993 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in fmalizing the document.


JF:lc

JOHN WAIHEE

GOVERNOR OF HAWAH



Mr. Bill Teplow c/o Teplow Geologic 1901 Harrison Street, Suite 1590 Oakland, California 94612

Dear Mr. Teplow:

P. 0. BOX 373


JAN 2 5 1993

WILliAM W. PATY, CHAIRPERSON

BOARD OF tAitO AltO NATURAL RESOURCES

DEPUTIES






PROGRAM LAND MANAGEMENT STATE PARKS WATER AND LAND DEVELOPMENT

Thank you for your December 28, 1992 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in fmalizing the document.


JF:lc

I I

TEL: Dec 28,92

'l'IIPLOif GllOLOG!C 19el Ha~ri•on St., su1~1 159e

Oakland, CA t4612 'l'el. £18-763•7&12 ra~ 818-7&3-2504

Manabu !avomori, Manater Departaen~ of Land and Ha~ural keeouroee r.o. !ox 373 Honolulu, HI 96889 'Peci!~ her' ~38, 19U

Dear Manabuo

15:26 No.032 P.02

As per your requeo~. I have rev:l.twecl the Hawaii Geotheraal Blowout Prevention Kanual. The rollowing are my coamentso

Lava tube, ash, and rubbla.contribute primarily to very h19h horizontal per11eabiHty wheru• vertical per111eab1l1t.y ~>an be extremely lim1ted and. controlled primarily by isolated, nearvertical fracturea.

2. Page 7,, last paragraph "Exploration well"

Recent geophysical work which I performed tor PGV inclicatee that eubsurtace ima;ino of xs-.a type f.ragtures may be possible using newly rafined 9eophy~ic~l techniques. It appear• froa thh work t.hat. ahallow ( ... seee!,.Jdepthl eteall•bearinq fractures can be preaisely locii'ted pdorrto drillino. Uee of th:l.• t:e.;hnique prlar to 4rUUnv.:mo.y, allow tor sat:ar place11ent of the surface drillin9 ·location &ius mora detailed plannin9 of ~:he depth to :Lnteuectton ;,; uf b19hMpreeeure fractures, &BJ)aaially in are~" whei:e no· ~:~revtoua dr:l.llint hae occurred.

If you would like to discuss these coamenta further, pert:icularly in rev~rd to tbe qeophysice, please qive me a call at PGV. tel. 808-965-6233 through January 18. After that l =•n be reached at the letterhead address and phone.

Deflt regards, T!IPLOW CUIOLOGIC

~'*-~~

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Gene Anderson Division Superintendent Nabors Loffland Drilling Company P.O. Box 418 Bakersfield, California 93302

Dear Mr. Anderson:

P. 0. BOX 373


JAN 2 5 1993


BOARD OF LAND AND NATURAl RESOURCES

DEPUTIES







Thank you for your December 22, 1992 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in fmalizing the document.


JF:lc

~~ l 1 ' l '

P.O. Box 418 NABORS LOFF'LAND DRILLING COMPANY Bokersfield, California 93302

3919 Rosedale Highway Bakersfield, California 93308 805-327-4695 805-327-4311 (Fax)

MR. MANABU TAGOMORI STATE OF HAWAII

December 22, 1992

DEPT. OF LAND AND NATURAL RESOURCES DIVISION OF WATER AND LAND DEVELOPMENT P.O. BOX373 HONOLULU, HAWAII 96809

Dear Mr. Tagomori:

~

:r-.- c: ;:~< o. c.---~

,-; ~~ ~

r :,_~ r l> c -< :.:rn 3.:::0 ~:>o -i

(!.)

"' = ,-.., CJ

. "' = D

= c.....J c.o

In reply to your request for comments on the draft of the "Hawaii Geothermal Blowout Prevention Manual", the following are my comments.

On Page 30, "Shut in Procedures" #2. WHILE TRIPPING should begin with:

a. Sound Alarm b. Lower drill string to place drill pipe tool joint just above the rotary table or if

drill collars are in preventers, lower drill collars until drill collar box is just above the rotary table.

c. Set slips (install D.C. clamp on D.C.'s) d. Install the full opening safety valve. e. Close the safety valve; close the annular preventer. f. Notify the company supervisor. g. Make up the kelly; open the safety valve. h. Record the drill pipe and annular pressure build up.

If you have any questions regarding my comments, please do not hesitate to contact me.

GA/sk

r Gene Anderson Division Superintendent

:x: Ill c; fil ~ --Pl 0

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. Pete Wygle

P. 0. BOX 373


JAI1 I 9 1993

Energy and Mineral Resources Engineer State of California Department of Conservation Division of Oil and Gas 1000 South Hill Road, Number 116 Ventura, California 93003-4458

Dear Mr. Wygle:


BOARD OF UlNO liND NATURAL R~SOURCES

OEPUfi~S

JOHN P. KEPPELEA, II DONA L. HANAIKE






Thank you for your December 10, 1992 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in finalizing the document.


JF:lc

STATE OF CAL!FORIHA - RESOURCES AGENCY

DEPARTMENT OF CONSERVATJ ON DIVISION OF OIL AND GAS 1000 SOUTH HILL ROAD, NUMBER 116 VENTURA, CA 93003-4456 (805) 654-4761

Mr. Manabu Tagomori STATE OF HAllA I I DEPARTMENT OF LAND AND NATURAL RESOURCES Division of Water and Land Development PO Box 373 Honolulu, HI 96809

Dear Mr. Tagomori,

d[CL.I/EO

ILSON. Governor ...:1 L L L

December 10, 1992

I have received a copy of your geothermal BOP manual, and it looks like Herb Wheeler at al have done a very good job for you. However, Dick Thomas, our geothermal officer in Sacramento and one of the authors of the technical investigation report that resulted in your contracting for the manual, thinks that there are a few areas in which I may be able to provide information of possible use before your manual is finalized.

To introduce myself, I am the llygle of "Hallmark and \lygle" mentioned in the references section of your manual as having written the BOPE book for the State of California. I have taught at the MMS-approved, IIOGA/IADC well control school at Ventura College, so I can probably hold my own in a discussion of oil and gas well blowout prevention, but I will be the first to admit that my actual experience with geothermal blowouts is extremely limited. I will, therefore, make no effort to pass myself off as any sort of an "expert" in the field.

The references section of your manual cites the 2nd edition (1976) of Manual M07, but we are up to the 5th edition (1985) and are about to produce the 6th edition in which we intend to expand our efforts along the geothermal line.

I am enclosing a draft of the geothermal section of the 6th edition. This change contains our first effort to classify geothermal BOPE so that we can require equipment that is tailored to the situation presented by a specific drilling proposal. This gives us a little more latitude than that indicated in your proposed manual, which shows only a diverter system and a "Cadillac" system.

I'm a little bit concerned about the fact that your proposed manual doesn't make a bigger deal of the value of cold water in geothermal kick response. It is mentioned late in the first paragraph on page

CALIFORNIA DIVISION OF OIL AND GAS December 10, 1992 SUBJECT: Hawaii Geothermal Blowout Prevention Manual Page 2 of 2 Pages

22, but cold water always seems to be the first thing that is mentioned when I have asked people in the geothermal or steam injection business about their plans for kick control. It is not mentioned at all in the KICK KILL PROCEDURES section on page 31.

Also, I think you should consider outlining shut-in procedures to be followed when drill collars are in the preventers. This possibility is not mentioned among the choices in the SHUT IN PROCEDURES section on pages 30 and 31, but kicks taken at this critical point in pipe-pulling operations have caused some of the major blowouts in recent history.

My only other comment at the moment has to do with a consistent typograpl>ic error in the manual. In the term H,S, the "2" is consistently superscripted as a power instead of subscripted as a term in a chemical formula should be.

I hope I have reswonded as you asked in your cover letter that I should. If there is any other help I can provide, please call me at the phone number in the letterhead.

Regards,

~ Pete Wygle Energy and Mineral Resources Engineer

JOHN WAIHEE

GOVERNOR OF HAWAII



Mr. W.R. Craddick Senior Vice President Water Resources International, Inc. 2828 Paa Street, Suite 2085 Honolulu, Hawaii 96819

Dear Mr. Craddick:

P. 0. BOX 373


JAN I 9 1993


BOARD OF LANO AND NAlURAL RESOURCES

OEPUliES



AQUATIC RESOURCES





PROGRAM lAND MANAGEMENT STATE PARKS


Thank you for your December 17, 1992 letter conveying your comments on the draft of the Hawaii Geothermal Blowout Prevention Manual. Your participation in our external review process is appreciated and your comments will certainly be considered in finalizing the document.


UTA~~-.-----Chief Engineer

JF:lc


DRAFT

State of Hawaii DEPARTMENT Of LAND AND NATURAL RE80URCE:5

Division Q! Water and Land Development

HAWAXX GEOTHERMAL BLOWOUT PREVENTXON MANUAL

State of Hawaii DEPARTMENT OF LAND AND NATURAL RESOURCES Division of Water and Land Development

Honolulu, Hawaii October 1992

• c

JOHN WAIHEE Governor


WILLIAM M. PATY, Chairperson, Member at Large

SHARON R. HIMENO, Member-at-Large

JOHN Y. ARISUMI, Maui Member

CHRISTOPHER J. YUEN, Hawaii Member

HERBERT K. APAKA, Kauai Member

DEPAR'l'MER'I' OF LARD ARD NA'l'URAL RESOURCES

WILLIAM M. PATY, Chairperson and Member Board of Land and Natural Resources

DONA HONAIKE, Deputy

JOHN P. KEPPLER, Deputy

ACKNOWLEDGEMENT

This document was prepared by R. A. Patterson & Associates, Kailua, Hawaii. for the Hawaii Department of Land and llatural Resources under Contract Agreement No. RCUH P. o. 4361021. The work was performed by Ralph A. Patterson, William L. D'Olier, and Herbert E. Wheeler. We wish to gratefully acknowledge the assistance of the staff of the Division of Water and Land Development, under the direction of Manabu Tagamori, and of the invaluable suggestions and assistance of all those who discussed the project with us.

Development of this Manual would not have been possible without the willing cooperation of many managers, technicians and professionals in the geothermal industry, various laboratories and academic institutions, and in other areas where their knowledge was helpful in presenting the review and recommendations of the Manual. The authors wish to acknowledge their help and candor, and their accumulated knowledge that has made our job easier.

PREFACE

The prevention of an uncontrolled well flow, commonly known as a "blowout", is

of vital importance for geothermal operators, drilling crews, state and county

regulators, and the general public. Geothermal well blowouts have not been the cause

of a signilicant number of fatalities, and the danger of fire, as in petroleum drilling,

is quite low. However, blowout incidents may have a negative impact on surface and

subsurface environments, cause resource waste, and develop unfavorable public

perceptions of geothermal activity. These concerns are powerful incentives to

operators and regulators to minimize the risks of a blowout.

This Manual has been developed to promote safety and good resource

management by discussing and describing blowout prevention as it can best be

practiced in Hawaii.

The intent of this Manual is to provide the necessary information to guide

regulators and operators in the practices and procedures, appropriate to each drilling

situation, that will minimize the risks of a blowout. The Manual is also intended to

promote an informed flexibility in blowout prevention practices, and to supplement

State and County regulations, especially those pertaining directly to drilling permits

and operations,!

I

This first edition of the Blowout Prevention Manual is a likely candidate for

revision as ~re drilling experience and information is gathered in the exploration and

development of Hawaii's geothermal resources.

1 Department of Land and Natural Resources (DLNR) Title 13, Subtitle 7. Water and Land Development; Chapter 183.

BOPPUnC!/R!P /loftlber 5, 1992

SUM.M.ARY

A summary of the Hawaii Geothermal Blowout Prevention Manual

will be included in the final document.

CONTENTS

Acknowledgement

Preface

Summary

L. SCOPE

II. GEOTHERMAL DRILLING RISKS IN HAWAII

III. GEOTHERMAL WELL PLANNING.

IV. BLOWOUT PREVENTION STACKS AND EQUIPMENT

'L._ EQUIPMENT TESTING AND INSPECTION

VI. DRILLING MONITORING PROCEDURES

VII. KICK CONTROL

VIII. BLOWOUT CLASSIFICATION


x.,_ POST COMPLETION BLOWOUT PREVENTION

XI. BLOWOUT PREVENTION IN SLIM HOLES

APPENDICES

A - Procedures for Manual Review and Revisions

B - Illustrations

C - References

D- Glossary

BOPCOm/RAP/RI'I:Iol!lb!r 11, 1'192 i

Page

1

2

6

12

17

19

29

32

34

37

38

The material in this Manual has been extracted from many key information

sources in order to present a complete and accurate review of the practices of

geothermal well control in Hawaii. In developing this Manual, a careful review of

drilling to date in the Kilauea East Rift Zone (KERZ) was conducted. The KERZ is where

nearly all Hawaii geothermal drilling has taken place, and is where most experts believe

the geothermal resources will be developed.

The general belief in the industry is that each area is "unique", since each

prospective geothermal area throughout the world has proven to have its own

characteristics in terms of drilling conditions, resource chemistry, geology, etc. While

this may be true in detail, some similarities do exist among geothermal areas located

in, or nearby, active volcanic areas. Thus, it has been helpful to briefly review well

control techniques and experiences from other similar volcanic areas around the world.

Some of the information gathered may have an influence on geothermal drilling in

Hawaii.

In order to review the experiences in Hawaii and in other geothermal areas

where active volcanism is prevalent, a great number of specific publications and

selected references were consulted. These are listed in AppendD C, References. In

addition, much of the information and many recommendations contained in this Manual

came from the accumulated experience of others who were consulted on various

elements of the items presented. A partial list of those consulted is also contained in

AppendD C.

This Manual defines a blowout prevention strategy for geothermal drilling in tbe

state of Hawaii. The essential components of this strategy are:

1) Improved risk analysis and well planning:.

2) Sound select:iml of blowout prevention sblcks and associated equipment.

3) Rigorous use of drilling monitoring procedures.

4) Expertise in kick control and blowout prevention equipment utilisation.

5) Jl!xceJlence in supervision and training of drilling personnel.

1

II .. GEOTHERMAL DRILLING RISKS IN HAWAII

THE VOLCANIC DOMAIII

The State of Hawaii consists of a chain of volcanic islands. Each island is a

composite of several volcanic eruptive centers built up by a succession of basaltic lava

flows, first as submarine deposits and subsequently as volcanic lands (or subaerial

deposits.) These basaltic lava flows form a sequence of near horizontal layers

consisting of hard crystalline flow rocks intebedded with lesser amounts of highly

variable rock debris. These flow sequences are evident in extensive outcrops and in

lithology logs from water well drilling.

Recently recognized geothermal resources are characterized by relatively small

prospective areas which are strongly associated with active or recent volcanism. The

highest probability areas for geothermal development overlie the volcanic rift zones

which are, or recently were, deep conduits for magma transport away from the volcanic

eruptive center. Hawaiian geothermal drilling to date has been confined to the active

Kilauea East Rift Zone (KERZ). In the KERZ, the magma (1900°F and higher) and lava

processes provide very high subsurface temperatures. Large amounts of meteoric

water (groundwater) and seawater intrude into the KERZ geothermal resource zones,

providing an abundant fluid supply for heat transfer.

Geothermal drilling in Hawaiian rift zones involves distinctive risks. A reasonable

initial identification of hazards and risks is now possible due to KERZ drilling

experience, combined with extensive studies by the Hawaii Volcano Observatory (HVO)

of KERZ rift zone function, structure and dynamic processes. This experience and

knowledge can be used to refine geothermal drilling programs and procedures to

minimize the risks of upsets and blowouts.

IUm.Z DRILLIIIIG TO DATE

The most valuable subsurface information for this Blowout Prevention Manual

comes from 12 deep geothermal wells and three exploratory slimholes drilled in the

KERZ since 1975. Rotary drilling rigs appropriate to the drilling objectives were used

on the twelve geothermal wells. Common drilling fluids used in this rotary drilling

are mud, water, aerated fluids and air. The well depths range between 1,670 to 12,500

feet below the ground surface. The Operators for the well drilling included four

2

private resource companies and one public sector research unit.

As of 1992, nine wells had penetrated prospective high temperature rocks and

seven of these were flow tested or manifested high temperature fluids. The resource

discovery well, HGP-A, completed in mid-1976, provided steam to a 3MW demonstration

electrical generation plant between 1981 and 1990. Two of the nine wells incurred

casing contained blowouts in 1991 upon unexpectedly encountering high pressured

geothermal fluids at shallow depths.

Three deep scientific observation holes (SOH) were drilled for resource

evaluation as continuously cored exploratory slimholes to 5,500-6,800 foot depths in

1990 and 1991. These SOHs helped to prove that favorable high temperatures prevail

over a ten mile interval along the KERZ. These holes did not encounter subsurface

conditions that involved significant blowout risks; however, special blowout prevention

equipment must be considered for future use of the slimhole technology in Hawaii.

SUBSURFACE COifDI'l'IOifS Ilf PROSPECTIVE AREAS

High temperatures, commonly in the 600-7001T range, are characteristic of

production zones in the volcanically active rift zones. The prospective geothermal

reservoir occurs in the roof rock above the deeper magma conduits. The well

completion targets are loci of permeable, highly conductive fault and fracture zones

which are generally enclosed by extensive secondary mineralization. Magma transport

downrift and its planar injection upward into the roof rock are the primary heat

sources for the geothermal resource.

The primary hazard of geothermal drilling in the volcanically active KERZ

is the currently unpredictable distribution of fault planes and major fractures. The

walls of these geologic structures are commonly sealed by secondary mineralization;

thus creating conduits for geothermal fluids. These fault and fracture conduits, can

present pressures ia.tbn g d &00 t,' '750 1 si above normal hydrostatic pressure,

particularly as they extend upward into cooler ground water regions. Unexpected

entry into such over pressured fault planes and fractures can cause substantial

upsets to all well control procedures.

Primary features such as lava tubes, irregular layers of ash and rubble, and

fractures contribute to very high vertical permeability, which can pose a problem

with loss of drilling fluid circulation to fluids and to low rock strengths. These

3

primary features seem to diminish down ward, but appear to extend to depths of 2000

feet.

An important feature of the KERZ is the seaward slip-faulting of its

southeastern flank caused by cross rift extensional stress. This seaward sliding of the

roof rock, coupled with seismicity, results in molten dike intrusions and fracturing.

Dike intrusions allow an abundant supply of heating and creates prospective

fracturing for the geothermal reservoir. All these features further contribute to low

rock strengths in the shallow near surface volcanics, which can be a problem when

attempting to locate a sound anchor for wellhead blowout prevention equipment.

The geohydrology of the KERZ involves large volumes of groundwater and

seawater. The relatively cool groundwater body, located just above sea level is

maintained by high annual rainfall and a high rate of infiltration. The KERZ geothermal

fluid system may be fed by a major groundwater basin on Mauna Loa's eastern flank.

Large volumes of seawater have the potential to penetrate the geothermal reservoir

through fractures at depth. Earthquakes in the region may cause existing fractures

to widen or may create new fractures. An increase in the salinity of the fluids

produced by the HGP-A well may have been caused by earthquake induced fractures.

Hydrostatic pressures are indicated to prevail in active rift zones, but these can be

escalated to higher fluid pressures in the temperature conditions prevailing. The

fresh and saline groundwater body, shown to prevail as deep as 2,500 feet in the Puna

geothermal field, may prove to be a general condition, but not one that can be

expected at every proposed well location.

SUMMARY ,

The Kj!!RZ geothermal drilling experiences prove two significant hazards that

must be addressed in a blowout prevention strategy for every proposed well:

1. Significant fault and fracture planes can be sealed conduits for

overpressured geothermal fluids. These features might eventually prove

to be predictable or detectable by drilling precursors. Blowout

prevention planning, equipments and procedures must be taken as a

critical requirement, ready for immediate and proficient use.

2. Weak and broken near surface volcanic rocks. The recognition of this

condition is a precursor to obtaininga reliable casing anchor, which is }\

4 'I

fundamental to safe blowout prevention by complete shut off. .

5

III. GEOTHERMAL WELL PLANNING

INTRODUCTION

The proven higher costs and uncertainties in Hawaiian geothermal drilling

operations are sound reasons to make an extraordinary investment in well planning.

Detailed planning is a must for each and every type of well because of the paucity of

subsurface information and the small base of drilling experience to date. Blowout

prevention is an integral element of geothermal well planning.

WELL PLAMIIDIG OBJEC'l'IVES

Safety The concept of safety must be carefully applied for all workers and

activities at the wellsite and for the public. A blowout prevention strategy is a crucial

part of any successful practice of safety in geothermal drilling; it is a necessity in

Hawaii.

Well PunctiDn Geothermal wells, if beneficial development is to be attained, must

convey and control very large quantities of fluid and energy, hopefully for the

greater part of the 30-year life that is expected in electric power systems. The HGP-A

discovery well demonstrated a reasonable performance in the production mode from

1983 to 1990.

Reasonable Cost Hawaiian geothermal wells are in the very costly category;

perhaps $2,500,000 per well is a representative minimal cost (1992$} if no significant

problems impact a good drilling plan. Competent planning might cost only 1 or 2\ of

the total cost of a successful well.

High quality well planning will assure a greater degree of safety and improved

well functions. Proper well planning will allow the Operator to be more confident in

responding to the upset conditions that can't be avoided and actual drilling

performance can be better assessed for continued improvements in future Hawaiian

geothermal wells.

DRILLIBG TARGETS AlfD WELL 'l'YPES

6

Geothermal drilling targets in the volcanic realm of Hawaii can be organized into

three simple classifications:

Explorat:im:l targets - to discover the resource, are generally identified by a

favorable combination of subsurface data indicating heat, fluids and fractures

(voids). Targets that can win drilling funds, but which present a high risk

exposure, are classified as exploratory by the Operator and participants.

Res t voir targets - to develop the resource, are generally qualified by high

temperatures, indicated fault planes and fracture systems or by nearby well

production data. The probability of penetrating both high temperatures and

fluid producing permeability intervals is high. Hawaiian geothermal reservoirs

are of the hydrothermal type {the predominate type now in worldwide

utilization.)

Supplemental targets - to conduct research on the resource, are comprised of

scientific and/or observational objectives which can contribute to a better

understanding of a geothermal resource and its enclosing subsurface

environment.

At the present level of knowledge in Hawaiian rift zones, no class of geothermal

drilling target can be confidently identified with lower blowout risks. Off rift

geothermal drilling targets may offer the perception of lower drilling risks, however,

no such drilling has been undertaken as of 1992.

Geothermal wells can be categorized as to function and several additional

features. The common types of wells include the following:

Expkral:ion well. Any well drilled to evaluate a prospective geothermal resource

target, usually at some sigrrifi.cant distance from an established or proven

geothermal reservoir. Hard and proximal subsurface data are not likely to be

available for a blowout prevention plan; diligent drilling monitoring procedures

(see Section VII) and casing plan flexibility are essential to blowout risk

reduction in exploration wells.

Production welL Any well designed to exploit the energy and fluids of a

BOPPWIIJC/IILD/Ioftllber lL 1992 7

geothermal reservoir for beneficial use or demonstration purpose. Blowout

prevention plans for production wells can be better specified to more

confidently known subsurface conditions.

Injecl::ion well. Any well designed to return the geothermal effluent to the

reservoir or other deep disposal zones. Injection wells will have blowout

prevention requirements similar to nearby production wells.

Slimhale. This type of geothermal well is identified by its small diameter

borehole, 6 to 4 inches, compared to the 17 t - 8 t inch hole diameter range

commonly used worldwide in the geothermal industry. The slimhole technology,

presently surging in evaluation and use in the petroleum industry, has a

distinct blowout risk and prevention requirement. The technology has been

safely introduced in the KERZ when HNEI accomplished three continuous

boreholes between 5500 and 6000 foot total depths in its Scientific Observation

Hole Program (1989-91). Discussion of the blowout prevention in slimholes is

presented in Section XII.

Deep versus shallow wells. These are terms of convenience in their general

usage; however, regulations may impose a legal definition on them. A historical

point of interest in the KERZ should be noted; several early geothermal

exploration holes, drilled safely with cable tools, encountered near boiling waters

at very shallow depths next to recent lava flow fissures and vents. Depth seems

to have no correlation with blowout risk in Hawaii's geothermal drilling to date.

However, it should be evident that relatively shallow blowouts in the porous

surface lava rocks and large fissures, broadly prevailing in Hawaii, could be

particularly difficult to kill.

Vertical versus deviated wells. It appears that Hawaiian geothermal wellfi.elds will

be extensively developed with deviated wellbores. Blowout prevention

requirements are not altered in any type of geothermal well by the vertical or

deviated course of its wellbore.

THE DRILLING PLAR

8

Every geothermal well proposed for funding and permitting will rl!quire a

drilling plan. Regardless of the geothermal well type, the drilling plan is the specific

technical document that should reflect the best thinking on how the well can be safely

constructed and its function obtained at reasonable cost. Safety is considered on a

broad front in a carefully prepared drilling plan. Commonly the deliberate actions to

optimize safety in geothermal drilling will be specified or reflected in four distinct

sections of the drilling plan, as follows:

1. Casing and cement. The intended function of the proposed well will be

a factor in casing design and cementing procedures selected. However,

the best available subsurface data sets on geology, hydrology, pressure

and temperature profiles, form~tion failure thresholds (fracture gradient),

together with the wellsite elevation, comprise the basis for increased

safety in drilling and quality of construction. The subsurface conditions

and well sire elevation are unique to each intended wellbore; the proposed

casing and cement plan must reflect a reasonable response to these

conditions. KERZ drilling experience reveals several special concerns for

blowout prevention.

' \·J

a. A preference to cement the surface casing (commonly 20 inch

diameter) below the water table can be acknowledged. Where the

groundwater table is within 600-800 feet below the surface, an

approximate 1,000 foot length of surface casing would meet this

objective. Where the groundwater table is much deeper, it could

be difficult to obtain a good cement sheath on surface casing set

at, say 1,700 feet, because of the presence of lost circulation zones

and incompetent rock in which to cement the casing shoe. Prudence

suggests that it is better to obtain a quality cement sheath on a

shorter length of surface casing.

1', ;·

(\ i ,. \, (} r·

----..; ' 'i\

{· \

' \

\

BOPPLAIIIIC/iLD/Io"* 11, 1!92

b. Independent of the quality of cement sheath obtained on surface

casing, the possibilities of fractures, other permeable paths to the

surface and low formation fracture gradients exist in the near

surface volcanic rocks penetrated by the surface casing. This

points to a serious risk in using a complete shut off (CSO) blowout

prevention system on the surface casing while drilling to the

intermediate casing depth. A CSO could force unexpected hot and

9

/

possibly pressured formation fluids to an external blowout (outside

the surface casing and cellar). External venting of this type can

pose more complex and precarious kill operations, and also threaten

the drilling rig's ground support. Accordingly, a diverting capacity

and large diameter flow line from the wellhead to a distant disposal

point is to be considered. This approach would contain such an

uncontrolled flow inside the surface casing and afford a safer kill

procedure confined to the wellbore.

c. Intermediate casing {commonly 13-3/8 inch diameter) may be set

at depths between 1,000,-2,500 feet below the surface casing shoe

if no unexpected geothermal fluids or anomalies are encountered.

The intermediate casing shoe depth should optimally be below the

major groundwater body. It should also be below extensive

fracturing that may reach up to the groundwater table, frequent

occurrence of lost circulation zones, and less competent volcanic

rock. Because the intermediate casing becomes the anchor casing

for the complete BOP equipment stack required to drill to total

depth, it is critical that the cement sheath in the open hole (17 ! inch diameter) annulus be of the highest possible quality. The

findings in the 17 ! inch drilled hole should be carefully studied.

Any adverse downhole conditions can be mitigated by cementing the

bottom portion of the intermediate casing as a liner in the open hole

interval (lapped several hundred feet into the bottom of surface

casing). The upper portion can be run and cemented as a tie back

I string inside the surface casing. Each of the two cement jobs

required should be of enhanced quality, should offset the external

natural hazards and should optimize the anchor for the complete

BOP equipment stack with its multiple CSO capacity over a full

range of drilling fluids.

2. Drilling fluids. The subsurface conditions encountered within the KERZ

are prompting the use of many drilling fluids ranging from moderate to

low density muds, water, aerated muds and water, to foam, and air.

Additionally, the ability to switch drilling fluids promptly is being

BOPPWIIIG/WLD/IoMb!r 11, 1.992 10

recognized as a cost effective advantage in greater well cont:.:-ol,. This

practice demands the use of BOP equipment compatible with a broad range

of drilling fluid options in a single wellbore. The diversity and flexibility

of drilling fluid utilization in Hawaii is encouraging, not only because all

fluids can be controlled by available BOP equipment, but because this

approach should lead directly to advanced safety margins, reduced

drilling times and lower costs. Drilling fluids and geothermal well control

are further discussed in Section VII.

3. Drilling Monitoring. This activity is usually integrated in thorough

drilling plans at many points. It is, however, quite important and

deserves more recognition as an effective method to reduce blowout risks.

A detailed consideration of drilling monitoring procedures is presented

in Section VII.

4. Blowout PreventiQn. Drilling plans may contain minimal specific

discussion of blowout preventiQn; a graphic sketch of the proposed BOP

equipment stack may be the lone obvious recognition of the subject.

However, a competent drilling plan will reflect, in its detailed provisions,

an Operator's blowout preventiQn strategy. The implementatiQn of risk

reduction will be evident in the casing, cementing and drilling fluid

provisions, in the drilling monitoring procedures, in proper training, and

finally in the BOP stack and its supplemental equipment. The drilling plan

should reveal the Operator's awareness that a blowout gm, happen, and

reflect the drilling supervisor's responsible determination that it has

been given the least possible chance to occur in the proposed well.

Blowout prevention is every Operator's final responsibility; it is achieved

first in the thinking and actions of all drillsite personnel through

training, by the practice of sound procedures, and by the use of reliable,

proper equipment.

BOPPLUIIIG/1LD/Ioftlb!r 11, 1m 11

IV- BLOWOUT PREVENTION STACKS AND EQUIPMENT

INTRODUCTION

Haw ali's geothermal drilling industry, still in a formative stage, has gained

sufficient experience and information to provide reasonable guidance to the

identification of more reliable and safer blowout prevention stacks and equipment. The

blowout prevention stack on the wellhead, when all other well control procedures have

failed, must function reliably to obtain a complete closure or effective control of

unexpected fluid flows from the wellbore. Blowout prevention stacks and related

equipment are not simple systems; they rely on integrated mechanical, hydraulic and

electrical processes to operate. Both redundancy and sophistication exist; however, the

risks of human error in critical situations have not been eliminated. Blowout

prevention systems require careful selection, maintenance, and repetitive training

of drilling crews to attain the reliability and safety which are essential in the final

defense against an actual blowout.

BOP DEFIIfiTIONS AlfD FUNCTIONS

1. Definitions

• The term blowout prevention equipment (BOP) here means the entire array

of equipment installed at the well to control kicks and prevent blowouts. It includes

the BOP stack, its activating system, kill and choke lines and manifolds, kelly cocks,

safety valves and all auxiliary equipment and monitoring devices. (see Glossary in

Appendix D for these terms).

• The BOP stack. as used here, is that combination of preventers, spools,

valves, and other equipment attached to the wellhead while drilling.

• A diverter stack is a BOP stack that includes an annular preventer, with a

vent line beneath. A valve is installed in the vent line so that the valve is open

whenever the annular preventer is closed, thus avoiding a complete shut off (CSO),

and diverting the flow of fluids away from the rig and personnel.

A full BOP stack is an array of preventers, spools, valves, and other equipment

attached to the wellhead such that complete shut off (CSO) is possible under all

conditions.

BOPS'!AaliUQUIP/IIEII/IILD/loftlahlr 11, 19!2 12

2. Functions

The main function of the BOP equipment is to safely control the flow of fluids

at the surface, either by diversion or by complete shut off. The equipment must be

adequate to handle a range of fluid types, pressures, and temperatures, and to

accommodate different drilling situations such as active drilling and tripping, or out

of the hole. The requirements of the BOP stack are to:

a. Close the top of the wellbore to prevent the release of fluids, or, to safely

divert the fluids away from the rig and personnel.

b. Allow safe, controlled release of shut in, pressured fluids through the choke

lines and manifold.

c. Allow pumping of fluids (usually mud or water) into the wellbore through kill

lines.

d. Allow vertical movement of the drill pipe without release of fluids.

Selection of BOP stacks and equipment should be made jointly by an experienced

geothermal drilling engineer and drilling supervisor. It is preferable to employ a

:.!supervisor

conditions.

that is experienced in Hawaii geothermal drilling experiences and ~H-('J ("\\c.<-

THE BOP AKCHOR

Complete shut off capability with a BOP stack requires the existence of a BOP

anchor. Three key factors are required for a sound BOP anchor:

1. A mechanically sound, continuous steel casing of reasonable length, which

probably will be 1000 feet or more, attached to the BOP stack.

2. A continuous and solid cement sheath in the annulus between the casing and

the rock wall of the wellbore.

3. An impermeable rock interval around the wellbore and cement sheath. The

entire section of rock need not be impermeable but priority is given to placing

and cementing the casing shoe in a thick interval of competent and impermeable

rock.

13

· IMPAC'I'S OF SUBSURFACE RISKS

Hawaii geothermal drilling has inherent risks due to the unpredictability of

subsurface conditions. Recognizing the risks and being prepared for all possible

conditions is the best form of blowout prevention. Subsurface conditions that may pose

the risk of a well blowout are listed below:

1. The almost certain inability to obtain a sound BOP anchor with surface casing

in the weak, often broken, and vertically permeable near surface volcanic rocks. As

discussed in Section n, if a "kick" occurs, these shallow rocks will not allow a CSO at

the wellhead without posing a significant risk of creating an externally vented well

casing blowout. (For discussion of externally vented blowouts, see Section vn.}

2. The unexpected entry while drilling into a major fault and fracture conduit

which is charged wfth overpressured geothermal fluids. Termination and control of

such events requires the certainty of a wellhead CSO with a full capacity BOP stack. l

The risk factors cited above reveal the importance of knowing when a BOP

anchor and consequent CSO capacity are available to prevent a blowout. If they are

not available, diversion of uncontrolled flows is judged to be the more prudent

response. On these fundamenW considerations, two basic BOP stacks are recommended

for Hawaii geothermal wells which are drilled with rotary rigs for exploration,

production or injection purposes.

BOP STACK RECOMMERDATIOI!IS

1. Diverter Stack (Figure !-Appendix B)

A diverter consisting of an annular preventer and a vent line should be

installed on the surface casing. In Hawaii, this casing is typically 20 inches in

diameter and is cemented in the 800 - 1,100 foot depth range. Incompetent near

surface volcanic rock and the high risk of cementing failure will not provide an

adequate BOP anchor. CSO is not intended with this equipment; diversion of

l In the KERZ, sudden geothermal fluid flows, which subsequently registered 500 to 700 psi shut-in wellhead pressures, were encountered at depths shallower than expected; in one case as shallow as 1,400 feet.

14

fluids is deliberate to avoid creating externally vented blowouts; ~nd for

personnel and rig safety.

2. Full BOP Stack (Figure 2)

A full BOP stack should be installed on the intermediate casing. In Hawaii, this

casing is typically 13-3/8 inches in diameter, and is cemented in the 2,000 -

3,500 foot depth range. This deeper casing, cement sheath, and host rock serves

~sa BOP anchor. The selection and arrangement of this stack allows for the use

' of a full range of drilling fluids (mud, water, aerated fluid, foam, air) and should

be a geothermal industry premium stack that is capable of confident, immediate

CSO over the range of temperatures and pressures anticipated. If a sufficient

BOP anchor is not obtained, this stack also has diverter capacity because of the

~/) - flo( -~T"(ve~t .. ·line, or, ban:!? box/blooi.e line, inc.luded ilJ th .. /'.·;R:ack. '~. ~ / -<'-A"· t:l. , '"" '·· •/. /· ,. "/.•· __ x.__/~'.,1-t;.<.h--'\)_L-<1

ADDITIONit RECOMMEifDA'l'IOBS I\ _.!. "/ c...- _{(_, .'/ r.J' -(~, .'~tCJJ• Jc .. , /) ) J ·!7' ('' f-. "' ' / ' . ' J' {-.4 , • j'' j-7·~. fi 1., D~ve~~. stack. ~Jh:" ~ve~~ ~c; sh:~~· haJ .,,~~- j~~:':U:~

characteristics: ..

A minimum pressure rating of 2,000 psi for all components.

b. Minimum vent line diameter of 12 inches.

c. A full opening valve on the vent line that opens automatically

when the annular preventer is closed; OR a 150 psi rupture

disk and a normally open valve.

d. The vent line directed through a muffler.

e. H2s abatement capability connected to the vent line.

2. Full BOP stack. The Full BOP stack should have the following

characteristics:

a. A minimum pressure rating of 3,000 psi for all components.

A pressure rating of 5,000 psi is recommended when indicated

by the risk analysis of the well. For temperature impacts on

pressure ratinqs, (See Fiqure 3)

b. Lower spool outlets - 2 inch diameter for a kill line and 4

inches for a choke line.

15

c. The pressure ratings for the kill and choke lines the same

as the stack.

d. All preventers should have high temperature rated ram

rubbers and packing units.

BOP EQUIPMENT RECOMMENDATIONS

1. Kill Line. 2 inch diameter kill line from pumps to spool. Two full

opening valves and one check valve at the spool. Fittings for an auxiliary

pump connection; pressure rating for the kill line the same as the stack.

The kill line is not to be used as a fill up line.

2. Choke Line and Choke Manifold. 4 inch choke line and manifold;

pressure rating the same as the stack. Two full opening gate valves next

to the spool; one of these valves remotely operated.

3. Actuating system. The actuating system should have an accumulator

that can perform all of the following after its power is shut off:

a. Close and open one ram preventer.

b. Close the annular preventer on the smallest drill pipe used.

c. Open a hydraulic valve on the choke line, if used.

The actuating system is to be located at least 50 feet from the well, with

two control stations -one at the drillers station on the rig and one at the /

· actuating system location.

I 4. other equipment. During drilling the following miscellaneous BOP

equipment is to be provided:

a. Opper and lower kelly cocks and a standpipe valve.

~b. A full opening safety valve, to fit any pipe in the hole. Kept

)

Lc. d.

on the rig floor.

An internal preventer, kept on the rig floor, with fittings to

adapt it to the safety valve.

Accurate pressure gauges on the stand pipe, choke manifold,

and other suitable places that may see wellbore pressure.

e. All flow lines and valves rated for high temperature service.

BOPS'!AClSUQUIP/IIIIf/ILD/Io'Mblr lL 1992 16

V. EQUIPMENT TESTING P~ND IN .SJ?ECTION

In general, a visual inspection and an initial pressure test should be made on

all BOP equipment when it is installed, before drilling out any casing plugs. The BOP

stack (preventers and spools, choke and kill lines, all valves and kelly cocks) should

be tested in the direction of blowout flow. In addition to the initial pressure and

operational test at time of installation, periodic operating tests should be made.

Pressure tests should subject the BOP stack to a minimum of 125% of the

maximum predicted surface pressure. If the casing is tested at the same time then

the test should not be more than 80\ of minimum internal yield of the casing at the

shoe. If a test plug is used, the full working pressure of the BOP stack can be tested;

a casing test would be made separately. Testing of the actuating system should

include tests to determine that:

1) The accumulator is fully charged to its rated working pressure;

2) The level of fluid is at the prescribed level for that particular unit;

3) Every valve is in good operating condition;

4) The unit itself is located properly with respect to the well;

5) The capacity of the accumulator is adequate to perform all necessary

functions including any kick control functions such as hydraulic valves

that are using the same unit for energy;

6) The accumulator pumps function properly;

7) The power supply to the accumulator pump motor will not be interrupted

during normal operations;

B) There is an adequate independent backup system that is ready to operate

properly; and

9) The control manifold is at least 50 feet from the well and a remote panel

is located at the driller's station.

10) All control valves are operating easily and properly, have unobstructed

access and easily identifiable controls.

The sequence of events to test the BOP stack and all other valves depends on

the stack configuration, but it is important that all equipment is tested, including the

annular preventer, pipe rams, CSO rams, upper and lower kelly cocks, safety valves,

internal preventers, standpipe valve, kill line, choke manifold and choke control valve,

17

internal preventers, standpipe valve, kill line, choke manifold and choke control valve,

pressure gauges, and any other items that are installed as part of the BOP equipment.

In addition to the initial testing of BOP equipment when it is first installed,

there should be frequent BOP testing and drills. The closing system should be

checked on each trip in or out of the hole and BOP drills should be held at least once

a week for each crew. It is most important that every member of the crew be familiar

with all aspects of the operation of the BOP equipment, along with all of the

accessories and monitoring devices that aid in detection of a kick. The main purpose

of drills is to train the crew to detect a kick and close the well in quickly. BOP drills

should cover all situations, while drilling, tripping, and with the drill string out of the

hole.

BOP'!!STIIC\B!II\WLD\Imlher U. 1!92 18

VI. DRILLING MONITORING PROCEDURES

INTRODUCTION

Operators commonly provide for some level of monitoring in the drilling of most

geothermal wells. All types of monitoring procedures will incur additional costs, which

may limit the selection of specific procedures. However, most Operators determine the

specific procedures in the context of what is known and not known about the

subsurface environment to be penetrated by the wellbore. This discussion of

monitoring will use the broad sense of the term, including mud logging.

Monitoring procedures may be defined as an array of continuous sensing actions

which attempt to accurately indicate subsurface conditions as the drill bit is advancing

through the rock formation.

MONITORING RATIONALE

Geothermal wells, drilled within the prospective, active volcanic rift zones of

Hawaii, merit carefully planned and integrated monitoring procedures. This view is

supported by two primary concerns. First, the subsurface geology, hydrology,

temperatures and pressures in the rock roof above the deep magma conduits, which

create the rift zone, are only partially known. Only 14 deep geothermal bores (11

wells and three scientific observation holes) have provided hard, factual subsurface

data as of mid-1992. Secondly, two geothermal wells have demonstrated that fault or

fracture conduits, charged with high pressure, high temperature fluids can extend

upward to relatively shallow depths from a deeper subsurface domain of >600°F

temperatures. These near vertical and planar conduits present both blowout risks

and significant geothermal energy production potential. This recent finding, proven

by drilling, has major implications. Geothermal drilling requires the evaluation and

more effective utilization of monitoring procedures as a supplemental strategy for

blowout prevention.

VITAL SECTORS

Monitoring focuses on three vital sectors during the drilling of a geothermal

well:

BOPMOilliJRIJG/iLD/IoMber 11, 1992 19

1. Drilling penetration rate and drill bit performance measurements. The

penetration rate, commonly measured and recorded in feet per hour,

indicates the mechanical progress of drilling in the host rock. Weight

on bit, rotational speed and torque are additional measurements that are

made to better understand the variations of the drilling penetration rate.

2. Drilling fluid circulation in the wellbore which clears the newly made hole

of drilled rock debris, cools and lubricates the rotating bit, and drilling

string. Importantly, the density and hydrostatic pressure gradient of the

drilling fluid are commonly used to control the formation fluids and

pressures encountered.

3. Physical conditions and resource potential of the newly penetrated rock

formation. The array of information gathered in this sector is commonly

presented in a continuous "mud log" graphic record over the entire

interval drilled.

The information products from the sectors discussed above have important

potential applications. Possible immediate improvements might be indicated in drilling

procedures, drilling fluid properties or casing plan in the well itself. Enhancements

in well design, drilling programs and/or cost reductions can be determined for future

wells. The information products of monitoring procedures, with careful integration and

evaluation, can make important contributions to an Operator's strategy of blowout

prevention.

OPTIMIZING BLOWOUT PREVEKTIOR

Any effective reduction in blowout risks is primarily contingent upon accurate

interpretation of monitoring data and ultimately depends on the decisions made, based

on this data. This must be achieved by the Operator. Having made the risk analysis,

written the drilling plan and obtained the funding for the well, the Operator's

geologist and drilling engineer presumably would be the most qualified persons to

establish the method by which the selected monitoring procedures would be used to

contribute to a blowout prevention plan. In prospective Hawaiian rift zones, the

prudent Operator, making careful use of monitoring information, can better identify

the potential for hot and overpressured fault and fracture conduits, and can better

prepare for penetration of such conduits and reduce impacts of ki.cks and lost

BOl'l«<lmJG/iLD/belh!lll,l9!2 20

circulation. Alternatively, a decision on whether or not to set casing can ·be. made,

particularly if a long open hole section is exposed above the interval of concern.

Critical data that may reveal the degree and/or immediacy of a blowout risk

. /~rfo ,Jtre probably first observed by key personnel of the drilling and mud logging

fV.r/ . . \{"I contractors. Exercising personal control of drill bit performance in making hole,

'Q ;:{' • r. '( drillers are the first to sense change at the bottom of the wellbore. Additionally,

A \r }\- / drillers must have an accurate, real time knowledge of the drilling fluid upflow in the

fr:· \' 1\/ annulus between drill pipe and the wall of the open hole. Gain or loss departures from

~~ ,,· r' l010~~ of t_he .drilling fluid pumped dow~ the drill pipe and t~rou~h the b~t orifi~es are f ,1\ , · . critical mdicators that, alone or w1th other corroborating mformation, s1gnal a

r' ,., (' ~'disruption of a normal drilling mode. ' ·\ ' -• (' 1 . ./ f

f' ('' '• 1 The mud logger and a supporting multiple sensor system continuously survey !' the changing rock features, formation fluids and temperature variations reflected in

the returning drilling fluid. This work is both time critical and time short because it

focuses evaluation on the narrow window of freshly exposed hole behind the

continuously advancing drill bit. Accordingly, good quality, competitive mud logging

has become a highly automated, computer assisted service with an impressive

reliability. The mud logger is the first to evaluate the formation gas and liquid

entries, via the returning drilling fluid, that may signal the penetration of high

temperature, high pressure conditions.

Operators of Hawaiian geothermal drilling projects need to assure that a high

level of cooperation in comprehending the norm and the upset hole conditions are

mutually practiced by their contracted drillers and mud loggers. The Operator's

drilling engineer and geologist should establish and maintain active communications

with these key specialists throughout the drilling process. It is essential that drillers

and mud loggers have reliable, instantly available electrical communication between

their work stations if monitoring procedures are to more effectively contribute to the

reduction of blowout risks. These simple procedures are intended to eliminate a

common problem: too often a key piece of new information is received, but is not

properly read, understood or communicated. Operators must lead their drillers and

loggers to consistent cooperation in monitoring procedures as an important protection

against the loss of well control. Inadequate responses to new well monitoring

information must be minimized in Hawaiian geothermal drilling.

BOPMOIITORIIG/WLD/Io9elber 11, 1m 21

. DRILLING FLUIDS AND GEOTHERMAL WELL CONTROL

All authoritative publications on blowout prevention {which to date exclusively

address oil and gas drilling) stress the role of drilling fluids in minimizing, if not

precluding, entries of normal or high pressured formation fluids into the wellbore

during the active drilling process. This is achieved by circulating a weighted mud or

salt water drilling fluid which creates an excess or overbalance of internal hydrostatic

pressure on every square inch of the open wellbore. The normal hydrostatic pressure

gradient for the formation fluids in Hawati rift zones should approximate 433 psi per

1,000 feet of vertical depth for fresh water and 442 psi per 1,000 feet for salt water.

This range of pressure gradients may prevail over much of the KERZ in the deep

geothermal zones because several geothermal wells were drilled through 2,500 foot

intervals of hot {600-700°F) prospective rock interval by circulating fresh water as a

wholly satisfactory drilling fluid. Well control was maintained confidently in these

operations and subsequently these fresh water drilled intervals yielded proven

geothermal fluids during flow tests following well completion. It should be noted that

the greater cooling capacity of water, as compared with mud drilling fluids, played a

positive role in these achievements.

Cooling by the circulation of drilling fluid is an inherent physical process in

geothermal well drilling. Where accelerated or optimized, the cooling process itself can

be recognized as a well control function. The efficient cooling of circulating drilling

fluids particularly will require an adequate surface cooling facility in the loop. Mud

cooling towers which allow the hot returning mud to fall in a baffle system against a

cool air draft are a standard equipment option for geothermal drilling. It is important

that mud QOOling towers be adequate for the heat load anticipated and that they be

carefully m;Lintained and monitored during use to assure that cooling is being

effectively' accomplished. Additionally, geothermal well control in Hawatian rift zones

requires ready access to an ample supply of cool water for wellbore circulation as a

well control option.

Both the specific KERZ drilling experience and the practice of world wide

geothermal drilling demonstrate the disinclination to drill with heavily weighted muds

or saline solutions as a preferred means of well control. This relates to the

expectation of finding fractures in the prospective hot zones which have much higher

permeability and production potential than a bulk rock interval of some uniform

primary (commonly lower) permeability. Fractures present the immediate risk of lost

BOPIIOmomc/llLD/Imlber 11, 1992 22

circulation and a possible well kick, particularly when overpressured fracture fluids . '

are released. The perceived benefits of significantly weighted drilling fluids

(significant overbalance - where the hydrostatic head of the fluid column exceeds the

formation fluid pressure) usually is lost immediately in geothermal wells which

successfully penetrate fractures. The loss of drilling fluid from the wellbore into

. {-1<'rmation fractures is accelerated in direct proportion to the overbalance due to

(Jf'-Y ~J ssively weighted mud. If, as indicated to date, blowout risks in Hawaiian rift

~ zones are predominantly fracture controlled and fracture specific, it does not appear

that excess weighting of drilling fluids will be a common means of blowout risk

reduction.

MONITORING INDICES FOR BLOWOUT PREVENTION

Monitoring procedures, taken as an aid to blowout risk reduction in Hawaiian

geothermal drilling, can be focused on a group of five categories, as discussed below.

The sequence of the categories is believed to be in order of importance when they are

examined with the assumption that the sudden encounter of high pressured geothermal

fluids in fractures constitutes the primary blowout hazard in these volcanic rift zones.

A. DRILLING WITH MUD OR WATER CIRCULATION

1. Bottom hole temperature variation. The blowout hazards in Hawaiian

rift zones have a strong correlation with high subsurface

temperatures. A working impression that 6000F and higher

temperatures were present below 4,000-foot depths under the

Kapoho-State geothermal leaseholds, and at greater depths uprift

in KERZ, may have prevailed before the KS-7 and 8 blowout events.

These wells respectively vented soollp- fluids from below 1,400 feet

and 620ilp- from below 3,476 feet in uncontrolled flows at the

wellheads. Bottom hole temperatures (BHT) cannot be measured in

the active drilling process because of the cooling induced by the

drilling fluid circulating around the rotating bit.

Alternatively, the exit temperature of the drilling fluid vented at

the wellhead annulus is continuously recorded. The sharper

excursions of increasing temperature with depth are the features

of interest in the automated plot of exit temperature. The mud

BOPIIOOIIJRJIG/WLD/IoMblr 11, 1992 23

logger can immediately read such temperature increases in the

context of the complete temperature profile (surface to current

depth) and detect possible correlations with events on other

indices. A supplemental temperature:depth record is frequently

obtained by measuring with maximum reading thermometers inside

the drill pipe at a stop immediately above the drill bit for some

consistent time interval (say 20 minutes) at some regular frequency

the Operator finds appropriate. This independent survey does not

obtain equilibrated BHTs; however, it provides a more discriminate

reference for the exit temperature plot. With respect to blowout risk

reduction, neither the existing BHT value or any specific high

~ temperature value has primary importance. Rather, it is sharply

rising temperatures, coincident with other dynamic events observed

in an integrated monitoring procedure, that are to be taken as a

caution or evidence that a blowout threshold is being approached.

2. Drilling penetration rate. Variations in drilling rate commonly

reflect rock conditions encountered by the drill bit, provided such

factors such as weight on bit, rotational speed and t.orque are

uniform or their coincident variations are understoocl. Increases

in drilling rate (a drilling break) can indicate a porous and

permeable interval containing formation fluids; fractured rock can

cause sudden erratic perturbations in all these mechanical drilling

indices. Major fractures in the KERZ can allow the drilling assembly

to free fall into open voids. The conseqv.ences of such a fracture

encounter are frequently immediate. Competent drillers will quickly

determine the status of their drilling fluid return flow in appraising

the situation and appropriate response, if required. Increases in

drilling rates coincident with the penetration of high pressure

zones are described in some blowout prevention treatises on the

conclusion that bits drill faster in underbalanced mud weights

approaching high pressured zones. It needs to be determined if

KERZ drilling experience, past or future, suggests any basis for

reading drilling rat"' variations as an indicator of penetration of

high pressures. One prudent option in drilling fractured, high

temperature intervals, especially with initial formation fluid entries

V{)L!J '/' / ::>identified in the return drilling fluid, is to deliberately reduce

~P~G~D/Io"!Ur 11, 1!92 24

penetration rate or briefly hold in a full circulation mode ·~o· confirm

drilling fluid system status and to observe more of the impact of

the formation fluids encountered.

Drilling fluid circulation. Accurate knowledge of the drilling fluid

condition, particularly its weight in pounds per gallon, and its

functioning in the wellbore, are critical to drilling with effective

well control. Any departure (gain or loss) from a 100\ return of

the pumped circulating volume, delivered through the drill pipe to

the drill bit, needs to be promptly evaluated as to magnitude and

meaning. Continuous measurement and recording of the drilling

fluid gain, loss, or 100% return is made in specific tanks (mud pits)

included in the fluid circulation loop. Either gain or loss of drilling

fluid must be taken as a warning of increasing blowout risk. A gain

is a reliable indicator of formation fluid entry into the wellbore

(kick). If well flow is indicated or suspected following a gain,

drilling should be halted, the kelly pulled above the rotary table,

the mud pump shut down and the exit flow line visually examined

for possible flow. If the well is flowing in these circumstances, the

annular preventer should be closed to identify pressure buildups

on both annulus and drill pipe. These pressures, when stable,

would identify the increases in mud weight and wellbore hydrostatic

pressure necessary to terminate the formation fluid inflow. An

evaluation of the option of circulating cool water in the wellbore

should be made if the kick is associated with a temperature

increase.

Partial or complete loss of drilling fluid returns is the more common

problem consequent to fracture penetration. Complete loss of

circulat.'i.on, followed by a falling fluid level in the wellbore annulus

is a most likely trigger for a blowout event. Drilling must be

halted, the drilling string pulled up (only to the first drill pipe tool

joint) and the preventer closed until the situation is evaluated and

a response determined.

Formation fluid entry. All geothermal fluid bearing zones, both

high and normally pressured, will be first identified by the drill bit

penetration with a subsequent charge of gases into the drilling

25

IJ I ( ,. r 1 1

'

fluid upflow in the annulus. Mud logging systems will automatically

measure and record carbon dioxide, hydrogen sulfide, methane and

ethanol in parts per million on a log scale whenever the drilling

fluid is being circulated. Although this information has a time lag

compared to the immediacy of a drilling break, it is the most

positive specific indicator that geothermal fluids have been

, : engountered. - , ·,-.r _.........~···-~

~·· ,· temperature increases, are a clear warning that a high pressure ,", "

Gas-cut drilling fluid returns, coupled with

zone of considerable flow potential may be at hand. With additional

penetration, geothermal formation liquid fractions may cause

' / ' '· : ( detectable salinity increases in the return drilling fluid. Salinity

.. ( ~~-" ,,. ' ' ( determinations are not an automated monitoring procedure, but are

,.,..,CJ; <;/'{:-:.< ·, • t ' '. ', ·• /! ; . optionally performed by the mud logger in evaluating fluid entry

4 pc. -. ·, r . , ' .. f ,:~ t/' . events. C t '} I , ~.,ttJ ·;

1'- . 'i O"f j;./ /)"- ., ! ' 5./ Secondary mineralization. Geothermal fluid bearing faults, fractures

/ and zones are predominantly enclosed in a sheath or seal of

' secondary minerals. Secondary minerals are continuously identified

\

and recorded in geothermal mud logging with the intent of

discerning, in correlation with the wellbore temperature profile, the

most prospective intervals for fluid production. Logic would

suggest that the larger hot fluid conduits, which present both

significant production potential and blowout risk, would likely have

a thicker sheath of secondary minerals. The extent to which this

prevails in the Hawaiian rift zones and to which it may be a

particular precursor to high pressured geothermal fluids in

fractures is not well known. Natural variations in the secondary

mineralization process, consequent to a new fracture opening for

geothermal fluid conduction, may be extreme; any secondary mineral

sheath could presage a fluid filled fracture or a fracture that is

completely sealed by mineralization, particularly in the active

faulting and fracturing of the KERZ. Whatever may be the present

view of this apparent index, it appears to merit careful evaluation

within the concept of integrated monitoring as a logical part of

blowout prevention strategy.

26

An optimal use of monitored drilling information in a blowout prevention stra~gy

requires the informed participation and responses of competent drillers and mud

loggers. A logical assignment of primary responsibility for the categories discussed

above would be:

Driller

drilling penetration rate

drilling fluid circulation

4-f/.; '/~ <( "'~ '" ··

iff!:~'! <!•··-'T~" .. .. C.. ~p;<rf.'::,-c_.d.• ;>' V

Logger

temperature variations

secondary mdneralization

formation fluid entries

Computer based graphic data presentations are increasingly used at the driller's

stations to quickly provide both present status and cumulative record on the drilling

and fluid circulation processes. Both caution and alarm thresholds can be set on the

incomdng real time information streams to alert drillers and supervisors to upset

conditions. Such systems offer an advantage to the blowout prevention objectives

necessary to Hawaiian geothermal drilling, provided that competence in their use is

created by diligent training.

The mud logging services contracted to most of the geothermal drilling

operations in the KERZ have been state of the art quality at the time of every

execution. Very substantial improvements in reliable automation have been made since

the mid-1980s. In summary, Operators have adequate monitoring procedures at hand

to reduce blowout risks. The driller's main focus is on immediate deviations from the

controlled drilling process, and the mud logger's main focus is on subsurface physical

~ _,.consequences of borehole adv. a.ncement. Blowouts are C()~f!:\.li)OI).,l.I.RE~~~<!~ci.J::>:r,._T~lti_£le {M;--~ warning signs of increa~g:.J;:i,aks. The Operator's drilling engineers and geologists,

with the close cooperation of drillers and mud logger!t, can more accurately recognize

such risks and more quickly act to control or reduce them with the drilling monitoring

procedures discussed here.

A final comment should be made on drilling fluid monitoring requirements wlille

tripping the drilling string. Frequently in geothermal well drilling with mud and

water, the hydrostatic pressure of the fluid has only a moderate overbalance on the

formation fluids. This is further reduced with the cessation of circulation immediately

before pulling the drill string, as for a new bit. In hot, prospective rock zones, the

large diameter drilling assembly moving up hole can swab, or pull formation fluids into

BOPMOIJTORmG/JLD/Jomla" ll, 1992 27

the borehole, by further reducing the hydrostatic pressure below the bit. The

greatest danger of swabbing occurs when pulling the first few stands of drill pipe

(drilling assembly just pulling off bottom). At this point, a careful confirmation of the

drilling fluid fill-up volume, required to hold the fluid level at the wellhead, is

essential. If the well fill-up volume is less than the volume of drill pipe pulled,

swabbing should be inferred, the bit returned to the bottom and the hole recirculated

to clear the formation fluids from the well. In summary, swabbing is a mechanism that

can and has caused blowouts. A slower pulling of the initial stands and the fill-up

check are the defensive procedures to use.

B. DRILLING WITH AIR, AERATED LIQUIDS OR FOAM

These drilling fluids are utilized in the underbalanced drilling option, which is

often employed in geothermal drilling, particularly in known vapor dominated

reservoirs. Air or aerated liquids drilling, sigrllfi.ed by substantial additional

equipment and service requirements, (air compressors, rotating head, banjo box, blooie

line, drilling muffler and H2s abatement backup) has been employed on a geothermal

exploration well in the KERZ. Expectedly, air and aerated fluids drilling will be used

and further evaluated in the Hawaii environment. Air drilling eases the driller's

concern with circulated fluid controls on formation fluids; the formation fluids, with

relatively unrestrained entry to the annulus, are transported to the surface and

through the drilling muffler for chemical and noise abatement before release to the

atmosphere. The mud logger's interpretation of rock and mineral cuttings is degraded

somewhat by the much reduced rock particle size produced by air drilling. otherwise

the drilling monitoring procedure discussed above will apply for the same objective /

of blowout .tisk reduction.

I

BOPMOmoRJJG/wtD/Iomher 11, 1'192 28

VII. KICK CONTROL

INTRODUCTION

In drilling terms, a 'kick' is often the first indication at the wellhead that there

are problems with control of formation pressure. A kick is defined as the entry of

formation fluids (water, steam, or gasses) into the well, which occurs because the

hydrostatic pressure exerted by the drilling fluids column has fallen below the

pressure of the formation fluids. If prompt action is not taken to control the kick and

to correct the pressure under balance, a blowout may follow. Some of the main causes

of these pressure imbalances are:

1. Insufficient drilling mud weight.

2. Failure to properly fill the hole with fluids during trips.

3. Swabbing when pulling pipe. If the drill string is pulled from the hole too

rapidly, the pressure may be reduced, allowing formation fluids into the

bore.

4. Lost circulation.

KICK IDENTIFICATION

There are a number of warning signs that indicate that a kick is occurring or

that it may soon occur. Some of these signs, which may not be present in all situations,

are:

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

/1.

An increase in the returning drilling fluids flow rate, while pumping at

a constant rate.

An increase in mud pit volume.

A continuing flow of fluids from the well when the pumps are shut down.

Hole fill up on trips is less than the calculated amount.

A pump pressure change and a pump stroke increase while drilling.

An increase in drill string weight.

A drilling break. (A sudden increase in penetration rate)

Gas cut mud or reduced mud weight at the flow line.

Lost circulation.

A rapid increase in flow line temperature. < ( + ·. 1 •. c (/ )v_...,.{v"'. , , . '-a-t'..(.'" ---~r . / ', -.

Each of the above warning signs individually does not positively identify a kick.

29

Each of the above warning signs individually does not positively identify a kick.

However, they do warn of a potential for a kick. Every driller and derrickman should

be expert in recognizing these indicators and all crew members should be trained to

take action. In geothermal drilling, in addition to being alert to the above warning

signs, it is of prime importance to: 1) monitor drilling fluid temperatures in and out

while drilling; 2) maintain a frequent and close analysis of the formation cuttings for

a change in mineralization; and 3) exert caution when drilling through formations

where lost circulation zones are expected. Difficulties or abnormal conditions with any

of these indications or procedures can also indicate of a potential kick.

SHUT IN PROCEDURES

The severity of a kick depends on the volume and pressure of the formation

fluid that is allowed to enter the hole. For this reason, it is desirable to shut the well

in as quickly as possible. When one or more warning signs of a !tick are observed,

procedures should be started to shut in the well. If there is doubt as to whether a

kick is occurring, shut in the well and check the pressures and other indicators.

Specific shut in procedures when one or more kick warning signs are observed

1. WHILE DRILLING



c. Close the annular preventer.


e. Record the drill pipe and annular pressure build up.

2. WHILE TRIPPING


b. Install the full opening safety valve.

c. Close the safety valve; close the annular preventer.


e. Make up the kelly; open the safety valve.

f. Record the drill pipe and annular pressure build up.

3. WHILE OUT OF THE HOLE

a. Close the well in immediately.

b. Record the pressure build up.

BOP!lelS/IiLD/I!!ll/lofelher 11, 1m 30

c. Notify the company supervisor.

d. Prepare for snubbing or stripping into the hole.

4. WHILE USING A DIVERTER



c. Open the d.iverter line valves.

d. Close the annular preventer.

e. Start pumping at a fast rate.


KICK KILL PROCEDURES

Several proven kick killing methods have been developed over the years, based

on the concept of constant bottom hole pressure. Two of the most common methods are

know as the "drillers" method and the "wait and weight" method. Rig personnel should

be familiar with, and trained in, these procedures.

Selection of the method to be used in a particular kick situation should be made

by an experienced, qualified drilling supervisor. The actual method used will depend

on knowledgeable considerations of surface pressure, type of influx, the time required

to execute the procedure, complexity of the procedure, down hole stresses that may

be present or introduced, and available equipment.

-~~~~~.Be-.-l!tll"e suggested procedures, to be modified by a knowledgeable

drilling supervisor to suit the particular conclli:ions existing at the time of the kick.

'---P"'~~c if/._,/ 1" ·~·-· ~,,.4,_,:, I -pf/,:; ), ~ r--~;H..-•·L~/1>'-'• -t!,,.l.~ ,t:~' C......

BOPmS/IILD/11!11/Iorelb!r 11, 1!92 31

VIII- BLOWOUT CLASSIFICATION

INTRODUCTION

Any uncontrolled flow of steam, brine or other well fluids constitutes a blowout.

A discharge of these fluids at the surface is usually taken as the basic identifier of a

blowout. However, surface discharge, if it occurs, is only the symptom or consequence of

the fundamental upset condition that results in a blowout.

In the context of Hawaii geothermal activities, a broader, yet more precise,

definition of a blowout can be stated as a ''loss of control of the natural pressures and

fluids encountered in the drilling of a geothermal well."

There are several types of geothermal well blowouts, varying in their severity and

in the techniques needed to control them. The impacts on surface and subsurface

environments, resource waste, and public perceptions of these incidents demand that

Operators and regulators minimize the risks of blowouts. The types of blowouts that may

be experienced in Hawaii include the following:

A. SURFACE BLOWOUTS f'!r_,_r_/, c ''--'

1. Casing Contained. An uncontrolled flow of steam or other fluids through

the casing and wellhead will result in the escape of fluids to the atmosphere.

This may result in unabated gas emissions and noise disruptive to the

surrounding community and the surface environment surrounding the well.

This type of blowout may cause minor to major damage to the wellhead, BOP

equipment stack, or drilling rig. Response to the blowout will depend on the

specific situation. Efforts will focus on wellhead repairs, control of fluid

discharge, and access to the area for specific procedures. The availability

of drilling fluid supplies (including water), and the condition of the drilling

string and casing will be key elements in an effective operation to regain well

control.

2. Externally Vented.

• Moderate case - low-to-moderate fluid venting outside the casing

or the cellar; the drilling rig, wellhead and BOP are generally

undamaged and operable. May or may not be disturbing to surrounding

BOPCLASS/WLD/Iulyl4, 1.992/Rif laltllb!r 11, 1.992 32

community. Responses may include grouting at the leak to terminate

surface flow.

• Worst Case - venting volume and/or velocity leads to rig collapse

and/or cratering around or near the wellhead. Response will probably

require a relief well if the hole doesn't bridge or collapse on its own,

thus terminating the flow.

/ B. UNDERGROUND BLOWOUTS .- .-;

Although this class of blowout lacks any surface display, the event could escalate

into a surface blowout if not recognized and resolved at an early time.

h High pressure fluid upflows, in the open hole, from a deep zone to a

shallower permeable zone (lower temperature reservoir or groundwater). Such

events may range from serious degradation or destruction of the open hole,

to minor resource loss and conservation problems. Response is generally to

subdue the flow with water, weighted muds, or cement plugs as required.

Additional casing/liner probably will be required, or the well may be plugged

with cement for redrill or suspension.

1.:_ High pressure fluid upflows, in the open hole, from a deep zone to an

escape by hydraulic fracturing at the deepest casing shoe, where the

formation (pressure) gradient is exceeded by higher fluid pressure from

the deep zone. Response as above in 1.

BOPCLASS/iLD/July 1!,1992/R!Y loYelber ll, m2 33


INTRODUCTION

The major cause of most blowouts is human error; either none of the crew or

the Operator's advisors recognizes an existing well control problem, or steps to control

the situation are not performed soon enough. Most blowouts are fully preventable by

properly trained drilling personnel. Thus, proper training of the crew is as important

to successful well control as is the proper selection and use of blowout prevention

equipment, as discussed in the preceding sections. The Hawaii conditions for

geothermal drilling require that every Operator recognize its prime responsibilities to

provide supervision and training that is several levels above the industry average.

Hawaii's geothermal drilling industry is still in a formative stage. Because there

is no pool of operators and drilling personnel thoroughly familiar with all potential

problems in Hawaii's geothermal resource areas, there is a need for operators, drilling

contractors and regulators to pay extraordinary attention to all elements of training

for their personnel. There must be a proper balance between practical, on-the-job

training, operational drills, and formal study for a wide range of individual experience

levels. In a few cases, drilling and monitoring crews will have worked together closely

in other geothermal areas, some of which may exhibit well control challenges similar

to Hawaii's. In other instances, crews will be made up of a mixture of individuals that

have not worked as a team before, and may have a larger percentage of new workers,

especially at lower skill levels in the drilling and production jobs.

An additional consideration in the Hawaii case is the known occurrences of

relatively hlgh levels of H2s gas in the geothermal resource. Proper well planning and

equipment ~lection can mitigate many of the hazards of Hls drilling in the well control

sense, but' it is necessary that all drilling crews have a clear understanding of the

dangers and rules that accompany drilling in known H2s zones.

SUPERVISORY EXPERIDCE

Although complete training for specific crews that will drill in Hawaii's

geothermal zones is of primary importance, the art of well control is not learned from

classroom training alone. Therefore, experienced supervisory personnel are vital to the

process of training the drilling crews, as well as in lending their experiences to the

ongoing supervision of the drilling. Drilling plans submitted should discuss the levels

BOPTRAIIIJG/RAP/R!V lovnher II. 1m 34

of experience of the drilling crews, supervisors, consultants and managers, with

comment on the methods to be taken to ensure that such experienced persons will be

directly involved while drilling activities are underway in Hawaii.

DRILLING TEAM TRAINII'IG AND DRILLS

The training of drilling teams, including supervisory, management and operating

personnel, in well control and blowout protection can be discussed in three basic

levels. Level one:training through formal courses that are infrequently offered by

industry and regulatory organizations, often at a regional or national level; level two:

the training that an Operator conducts on a more or less formal, or classroom, basis

with its drilling supervisors, drilling crews, and others who directly support its Hawaii

drilling operations ; level three: Operators must have a program of drills that ensure

all personnel actually have 'hands-on' experience with the installed blowout prevention

equipment.

A number of organizations conduct training and certification in well control,

mainly directed toward the petroleum drilling industry. However, recent classes in

the specifics of geothermal well control have been held by a cooperative effort of the

Geothermal Resources Council and the Rational Geothermal Association, with funding

in part by the Federal Department of Energy. This course has been approved by the

Federal Minerals Management Service for training and certification in well control

subjects, and is recommended for supervisory and other drilling personnel, as an

indication of the level of specific well control training and experiences of these

personnel assigned to Hawaii drilling tasks. There are no plans to hold these formal

courses often, and most certainly not in concert with specific drilling schedules of

individual projects. Therefore, each Operator and drilling contractor will need to

supplement the experiences of their supervisory personnel with direct team training

pointed toward developing an integrated effort for Hawaiian projects.

Operators should outline the formal (classroom) training proposed for drilling

personnel, with specific references to 'kick' recognition and blowout prevention,

including monitoring systems, equipment, and drilling procedures. A number of study

guides and references are available for these purposes; publications to be used should

be listed in drilling plans so that they can be reviewed by regulatory review

personnel. A list of specific references is not included in this Manual because these

publications may become obsolete by newer editions. Appendix C, References, contains

documents and sources used in preparing this Manual, and should be consulted for

35

suitability to each drilling plan.

In addition to classroom training and periodic updates as drill crews may shift

or the drilling may enter new phases, blowout prevention drills should be conducted

on a regular {but unannounced) basis to provide further training, and to keep crews

focussed on the possibilities of well kicks, and blowouts. Crews should be familiar with

the equipment in use, and be able to properly and safely shut in the well before a

control problem becomes dangerous to personnel or the well itself. These drills should

be directed at well control and proper blowout prevention procedures in three basic

situations - when drilling ahead, when 'tripping out' of the well, and when the drill

pipe is out of the wellbore.

other blowout prevention and general safety training - both informal and on

the-job situations, should be outlined in the drilling plan. Subjects covered should

include new employee orientation, visitor briefings and general safety training. Formal

training sessions, regular review training and blowout prevention drills held should

be noted in the daily reports of the drilling operation.

BOPI'RAIIIJG/I!P/REY llmUr 11, 1992 36

x. POST COMPLETION BLOWOC PREVENTION

. ) ( ~ ;ti''--·~-' .. .,/ fVtU' 1 "

l-vc-' It is important to realiz that blowout risks are not restricted to the initial

drilling and completion of a eothermal well. At a much lower incidence rate, blowouts

can occur at producing w s and at shut-in idle wells. Wellhead equipment should be

recognized as vulnerable to natural surface conditions and vandalism. The capacity,

integrity, and security of geothermal wellhead equipment are all the responsibility of

a production engineering expertise which is not within the scope of this Blowout

Prevention Manual.

Two areas of subsurface risks to casing string integrity in existing Hawaiian

geothermal wells should be noted. The corrosion potential of wellbore fluids, in both

the production and shut-in (static) modes should be identified. Baseline chemistry and

casing evaluation procedures should be established shortly after well completion. The

objectives here are to assure and prolong casing integrity, and to preclude any

blowout consequent to a casing failure due to corrosion. Wells that have been tested

or have produced high temperature fluids, and then are shut-in for periods of time,

particularly require regular and accurate monitoring of casing conditions. Temperature

decreases imposed by the active Hawaiian ground water regime can accelerate Hls

corrosion in shallow casing strings in idle wells. Finally, the risk of casing failure in

rift z.one er~ptions and earthquakes. (shallow fa~t mo.vements, ground ~r/tion g.r-:rotational failures) s.hould be recogmzf71 .. &-_,;., ·Y......, "- {r:a./c-1 ''r '/., . · (r_ z;;:::.· ~,C.--~ d~· ·'(I tuC ((. ~ e.-f• () tC.•c.. ·1.. ·(/ .... (-;.{c.·/, h

Blowout prevention requirements during remedial work, redrills, recompletions

and abandonments, in all geothermal wells, must be evaluated and provided for by

the same process of consideration required in every new geothermal well drilling

permit proposal.

37

XII- BLOWOUT PREVENTION IN S:LIMHOLES:

IKTRODUCTIOif

Deep drilling with slimhole (approximately 4-6 inch bit diameters) technology

and equipment has achieved major advances in the mining industry in the last several

decades. However, the mining drilling environment does not present pressure control

problems comparable to those encountered in petroleum and geothermal drilling. For

this reason, well control practices in slimholes were poorly understood until recently.

This hindered an expanding use of the technology. However, the technical and

economic advantages of slimholes have recently registered w:ith several petroleum

companies; Amoco Production Company has particularly investigated the requirements

of well control and blowout prevention in slimhole drilling.!

KEY ATTRIBUTES

Much smaller volumes of drilling fluids are circulated in slimholes. Kicks of any

volume are of more consequence, and immediate detection of fluid entry, or lost

circulation, is critical. Quantitative electromagnetic flow meters are used to measure

drilling fluid entry and exit volumes at the wellhead. These flow meters are reliable

and accurate, measuring gains of one barrel or less as compared to pit gains of 15

barrels or more as frequent kick events in the standard drilling mode. Unfortunately,

the much greater size of this type of meter required for standard diameter· wellbores

make them cost prohibitive. Another feature of importance is the high annular

pressure loss (APL) incurred by drilling fluid circulation in slimholes. The higher

rotary speeds (RPM) used in slimholes also adds, with the APL, a substantial increase

(overbalance) above the hydrostatic pressure of the drilling fluid on the borehole

while actively drilling or coring. This physical phenomena relates to the very small

annuli between drill tubulars and the rock wall. The high APL can be used

advantageously to effect a dynamic kill and control of formation fluid entry below

2,500-foot depths in slimhole by accelerating the pumping rate to maximum levels in

I Well Control Methods and Practices in Small-Diameter Wellbores; D. J. Bode, et al Amoco Production Co., October 1989. (Available from the Society of Petroleum Engineers, P. 0. Box 833836, Richardson, Texas 75083-3836; Telephone 214-669-3377.)

BOPSOB/iLD/R!V llo9elle: ll, 1992 38

circulating out the intruding fluids. In summary, blowout prevention in slimholes

requires special training, precision flowmeters, real time data presentation and

dynamic kill proficiency. It is likely that additional slimhole drilling will be considered

in Hawaii geothermal exploration and development; Operators should carefully evaluate

the Amoco paper referenced when developing plans for these boreholes.

BOPSOH/wtD/R!'IIO'Mber ll, 1992 39


APPENDIX A

MANUAL REVIEW AND REVISIONS

APPENDIX A.

MANUAL REVIEW AIID REVISION

Geothermal drilling experience in Hawaii, as of mid 1992, has been quite limited.

Only 14 deep geothermal boreholes had been drilled, and these were located on only

one prospective feature, the KERZ. Reasonable increases in geothermal drilling in the

KERZ, and perhaps other areas, can be anticipated. New operational and regulatory

experiences should accumulate in the next few years.

This Blowout Prevention Manual can best be accepted as a first edition. Ideally,

it should serve as a working reference for; operators and regulators in a cooperative

approach to the achievement of blowout risk reduction.

It is recommended that this Manual be reviewed and revised within 5 years of

its date of issue by DLNR. Such a time interval seems ample for the collection of new

operating information and for a reasonable application of the blowout prevention

procedures recommended in the Manual. Frequent and informed discussion of blowout

prevention procedures between operators and regulators could prove to be one of the

most important consequences of the use of this Manual.

DLNR authorities might consider a workshop process as an appropriate element

of the review process. Both Hawaiian geothermal operators, and those working

elsewhere in similar volcanic domains, could join DLNR in a thorough evaluation of

blowout prevention in geothermal drilling. Such an invitational workshop might best

be conducted 6 to 8 months before the first revision of this Manual.

'

I

BOPRri!SIOIHPPIID A/ILD,._. 1!,1992 APPENDIX A-1


APPENDIX 8

ILLUSTRATIONS

'·

HAWAII GEOTHERMAL DIVERTER STACK

Fi9ure I.

A 2M ANNULAR PREVENTER


API ARRANGEMENT SA

2000 PSI

s

HAWAII GEOTHERMAL FULL BOP STACK

Filjure 2.

ROTATING HEAD

G I When usin11 air

'installed an tap of ANNULAR PREVENTER

RAM PREVENTER

RAM PREVENTER


CHECK VALVE

KILL 2.. -{:::-f.@~ I

API ARRANGEMENT RSRS RRA

MIN. 3000 PSI

A

R

R

s

R

R

ANNULAR PREVENTER

Remotely operated -VALVE

VENT/BLOOIE 12"

BLIND RAM

Remotely operated VALVE

CHOKE 4''

PIPE RAM

FIGURE 3

In Hawaii, where wellhead temperatures in excess of 600°F may occur, Operators

must consider the pressure derating of steel due to elevated temperatures when

selecting wellhead equipment. The table below, from the American Petroleum Institute

{API) Specification 6A, provides the recommended working temperatures for steel at

high temperatures; this table goes only to 6SQ0p.

In addition to the steel in wellhead equipment, the temperatures found in

Hawaii far exceed the temperature ratings of elastomers found in most BOP equipment.

Operators often use all steel rams in ram type preventers for a more effective seal.

The API recognizes temperature ratings of elastomers up to 2SQ0p, but some

manufacturers can now produce elastomers that are rated to 420°F.

BOPFICIJII3111/~ 11, M92 APPENDIX B, FIG 3 -1

'

RECOMMENDED WORKING PRESSURES AT ELEVATED TEMPERATURES

E. 1 Pressure-Temperature Derating. The maximum working pressure ratings given in this section are applicable to steel parts of the wellhead shell or pressure containing structure, such as bodies, bonnets, covers, end flanges, metallic ring gaskets, welding ends, bolts, and nuts for metal temperatures between 20f and 650f (-29 and 3430C). These ratings do not apply to any non-metallic resilient sealing materials or plastic sealing materials, as covered in Par. 1.4.4.

Maximum Working

Pressure, psi (Bar)

TABLE E.1 PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS

(See Par. 1.2.4) (I BAR: 1111 kPa)

(See f(J"ew<J"d fer ExpilnatiJn ci Unis)

Temperature, F f-c)

0

(-29 to 121) 300 (149) 350 ( 177) 400 (204)

2000 (138.0) 1955 (134.8) 1905 (131.4) 1860 (128.2) 3000 (207.0) 2930 (202.0) 2880 (197.2) 2785 (192.0)

sooo* (345. o) 4980 (336.5) 4765 (323.5) 4645 (320.3)

1018 net app~ to ml psi 68X amttians

Maximum Working

Pressure, psi (Bar)

TABLE E.1-Continued PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS

(See Par. 1.2.4) (1 m = 1111 kPa)

Temperature, F ~)

500 (260) 550 (288) 600 (316) 650 (343)

1735 (119.6) 1635 ( 113. 7) 1540 ( 106.2) 1430 (93. 6) 2605 (179.6) 2455 (169. 3) 2310 (159.3) 2145 (147.9)

4340 (299. 2) 4090 (232.0) 3850 (285.5) 3575 (246.5)

450 (232)

1810 (124.8) 2715 (187.2)

4525 (312. O)

BOPFIGURE 3 HEI/Ottllber 1•, 1992 A P P E N D I X B, F I G 3 -2


APPENDIX C

REFERENCES

APPENDIX C

REFERENCES

Adams, N., Well Control Problems and Solutions, Petroleum Publishing Company, 1980.

An Applicant Guide to State Permits and Approvals for Land and Water Use Development, Department of Planning and Economic Development, State of Hawaii/Coastal Zone Management, 1986.

API Recommended Practices For Safe Drilling of Wells Containing Hls - RP49, The American Petroleum Institute, 1974.

Blowout Prevention Equipment Systems for Drilling Wells - RP 53, 2nd Ed. The American Petroleum Institute, 1984.

Bode, D. J., Noffke, R. B., and H. V. Nickens, Amoco Production Company, "Well _,/ Control Methods and Practices in Small-Diameter Wellbores", Society of Petroleum Engineers, October 1989,

Diener, D., Introduction to Well ControL Petroleum Extension Service, University of Texas at Austin, 1981.

Goins, W. C., Blowout Prevention Practical Drilling Technology - Volume 1, Gulf Publishing Company

Hallmark and Wygle, Oil and Gas Blowout Prevention in California - ManualiM07, 2nd Edition, California Division of Oil and Gas, 1978.

Hills, A., Overview of the status. Development Approach and Financial Feasibility, Department of Business and Economic Development, State of Hawaii, 1988.

Planning for Drilling in H2S Zones An Outline of Safety and Health Procedures, Petroleum Extension Service, University of Texas at Austin, 1978.

Rowley, J. "Geothermal Standards .. A Decade of Leadership Continues" Geothermal Resources Council Bulletin, December 1991.

Regulations and Rules of Practice & Procedure Geothermal. State of Nevada.

Rules for Geothermal and Cable System Development Planning. Title 13 -Administrative Rules, Department of Land and Natural Resources, SubTitle 7. Water and Land Development, Chapter 185. State of Hawaii.

Rules on Leasing and Drilling of Geothermal Resources. Title 13 -Administrative Rules, Department of Land and Natural Resources, Sub-Title 7. Water and Land Development, Chapter 183. State of Hawaii.

State Wide Geothermal Regulations. California Administrative Code - Title 14, Natural Resources; Chapter 4, Sub- Chapter 4 - State of California.

Sumida, Gerald A., Alternative Approaches to the Legal. Institutional and

APPENDIX C-1

•" Financial Aspects of Developing and Inter-Island Electrical Transmission Cable System, Carlsmith, Wichman, Case, Mukai and Ishiki and First Interstate Cogeneration Capital Associates for the Department of Planning and Economic Development, state of Hawaii, April 1986.

Thomas, Richard, Whiting, R., Moore, J., and Milner, D., Independent Technical Investigation of the Puna Geothermal Venture Unplanned steam Release, June 12 and 13. 1991 Puna Hawaii, for the state of Hawaii/County of Hawaii, July 1991.

BOPI!mRDC!HPI'DD A/IAP/IIIMblrll, 1992 APPENDIX C-2

' .


APPENDIX D

GLOSSARY

APPENDIX D

GLOSSARY

A

accumulator n: 1. on a drilling rig, the storage device for nitrogen-pressurized hydraulic fluid, which is used in closing the blowout preventers.

annular blowout preventer n: a large valve, usually installed above the ram preventers, that forms a seal in the annular space between the pipe or kelly and wellbore or, if no pipe is present, on the wellbore itself.

API abbr: American Petroleum Institute

B

BHP abbr: bottom hole pressure.

BHT abbr: bottom hole temperature.

blowout n; A blowout is an uncontrolled flow of formation fluids or gas from a well bore into the atmosphere or into lower pressure subsurface zones. A blowout occurs when formation pressure exceeds the pressure applied by the column of drilling fluid.!

BOP equipment n: The entire array of equipment installed at the well to detect and control kicks and prevent blowouts. It includes the BOP stack, its actuating system, kill and choke lines, kelly cocks, safety valves and all other auxiliary equipment and monitoring devices.

bottom hole temperature n: The temperature of the fluids at the bottom of the hole. While drilling, these temperatures may be measured by minimum reading temperature devices, which only record temperatures above a designed minimum, and may not provide an accurate bottom hole temperature. Bottom hole temperature readings should be recorded after a period of fluids circulation at a particular depth, in order to stabilize the reading.

blowout preventer n: the equipment installed at the wellhead to prevent or control the escape of high pressure formation fluids, either in the annular space between the casing and drill pipe or in an open hole (i.e., hole with no drill pipe) during drilling and completion operations. The blowout preventer is located beneath the rig at the surface See annular blowout preventer and ram blowout preventer.

BOP abbr: blowout preventer

I Rotary Drilling BLOWOUT PREVENTION Unit III, Lesson 3; Petroleum Extension Service, The University of Texas at Austin, Austin Texas, in cooperation with the International Association of Drilling Contractors, Houston Texas. 1980; 97 pages.

BOPCLOSSART/IAP,.._. 11. 1.9!2 Appendix D-1

:BOP stack n: The array of preventers, spools, valves and all other equipment attached to the well head while drilling.

borehole n: the wellbore; the hole made by drilling or boring.

c

casing n. steel pipe, cemented in the wellbore to protect it against external fluids and rock conditions, and to facilitate the reliable and safe production of geothermal fluids from the well.

cap rock n: 1. relatively impermeable rock overlying a geothermal reservoir that tends to prevent migration of formation fluids out of the reservoir.

casing n: steel pipe cemented in a geothermal well to protect the wellbore from external fluids and rock.

cellar n: a pit in the ground to provide additional height between the rig floor and the wellhead, and to accommodate the installation of blowout preventers, rathole, mousehole, and so forth. It also collects drainage water and other fluids for subsequent disposal.

cementing n: the application of a liquid slurry of cement and water to various points inside or outside the casing.

competent rock n. (in wellbores) any rock that stands without support in the drilled wellbore can be described as competent. Beds of ash, or loose volcanic clastics, are vulnerable to failure in open wellbores, and are thus considered to be incompetent rock.

complete shut off n. a full closure and containment of wellbore fluids and pressure at the wellhead.

conductor n: 1. a short string of large-diameter casing used to keep the top of the wellbore open and to provide a means of conveying the up-flowing drilling fluid from the wellbore to the mud pit. 2. a boot.

CSO abbe: complete shut off. I

D

diverter n: a system used to control well blowouts when drilling at relatively shallow depths by directing the flow away from the rig. The diverter is part of the BOP stack that includes an annular preventer with a vent line beneath. A valve on the vent line is installed so that it is opened whenever the annular preventer is closed.

drill coDar n: a heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem to provide a pendulous effect to the drill stem.

drilling fluid n: a circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface. While a mixture of clay, water, and other chemical additives is the most common drilling fluid, wells can also be drilled using air, gas, or water as the drilling fluid. Also called circulating fluid. See mud.

Appendix D-2

. . · drilling spool n: a spacer used as part of the wellhead equipment. It provides room

between various wellhead devices (as the blowout preventers) so that devices in the drill stem (as a tool joint) can be suspended in it.

drill pipe n: the heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe are coupled together by means of tool joints.

drill string n: the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit. Often, the term is loosely applied to include both drill pipe and drill collars. Compare drill stem.

F

flange n: a projecting rim or edge (as on pipe fittings and opening in pumps and vessels), usually drilled with holes to allow bolting to other flanged fittings.

formation pressure n: the force exerted by fluids in a formation, recorded in the hole at the level of the formation with the well shut in. Also called reservoir pressure or shut-in bottom-hole pressure. See reservoir pressure.

J

joint n: a single length of drill pipe or of drill collar, casing, or tubing, that has threaded connections at both ends. Several joints, screwed together, constitute a stand of pipe.

K

kelly n: the heavy steel member, four-or six-sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa.

kelly cock n: a valve installed between the swivel and the kelly. high-pressure backflow begins inside the drill stem, the valve is closed pressure off the swivel and rotary hose. See kelly.

When a to keep

kick n: an entry of water, gas, or other formation fluid into the wellbore. It occurs because the hydrostatic pressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation drilled. If prompt action is not taken to control the kick or kill the well, a blowout will occur.

kill line n: a high pressure line that connects the mud pump and the well and through which heavy drilling fluid can be pumped into the well to control a threatened blowout.

L

L.C. ibbc: lost circulation

log n: a systematic recording of data, as from the driller's log, mud log, electrical well log, or radioactivity log. Many different logs are run in wells to obtain various characteristics of downhole formations. v: to record data.

Appendix D-3

' . :lost circulation n: the loss of quantities of any drilling fluid to a formation, usually in

cavernous, fissured, or highly permeable beds, evidenced by the complete or partial failure of the fluid to return to the surface as it is being circulated in the hole. Lost circulation can lead to a kick, which, if not controlled, can lead to a blowout.

M

manifold n: an accessory system of piping to a main p1pmg system (or another conductor) that serves to divide a flow into several parts, to combine several flows into one, or to reroute a flow to any one of several possible destinations.

mud n: the liquid circulated through the wellbore during rotary drilling and workover operations. In addition to its function of bringing cuttings to the surface, drilling mud cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressures, and prevent loss of fluids to the formation. Although it was originally a suspension of earth solids (especially clays) in water, the mud used in modern drilling operations is a more complex, three-phase mixture of liquids, reactive solids, and inert solids. The liquid phase may be fresh water, and may contain one or more conditioners. See drilling fluid.

mud logging n: the recording of information derived from examination and analysis of formation cuttings suspended in the mud or drilling fluid, and circulated out of the hole. A portion of the mud is diverted through a gas-detecting device. Cuttings brought up by the mud are examined to detect potential geothermal production intervals. Mud logging is often carried out in a portable laboratory set up near the well.

mud pits n pl: a series of open tanks, usually made of steel plates, through which the drilling mud is cycled to allow sand and sediments to settle out. Additives are mixed with the mud in the pits, and the' fluid is temporarily stored there before being pumped back into the well. Modern rotary drilling rigs are generally provided with three or more pits, usually fabricated steel tanks fitted with built-in piping, valves, and mud agitators. Mud pits are also called shaker pits, settling pits, and suction pits, depending on their main purpose. Also called mud tanks.

mud weight n: a measure of the density of a drilling fluid expressed as pounds per gallon (ppg), pounds per cubic foot (lb/ft3), or kilograms per cubic meter (kg/m3). Mud weight is directly related to the amount of pressure the column of drilling mud exerts at the bottom of the hole.

p

permeability n: 1. a measure of the ease with which fluids can flow through a porous rock. 2. the fluid conductivity of a porous medium. 3. the ability of a fluid to flow within the interconnected network of a porous medium.

pipe ram n: a sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead. See and blowout preventer.

pit-level indicator n: one of a series of devices that continuously monitors the level of the drilling mud in the mud pits. The indicator usually consists of float devices in the mud pits that sense the mud level and transmit data to a recording and alarm device (called pit-volume recorder) mounted near the driller's position on the rig floor. If the mud level drops too low or rises too high, the alarm sounds to warn the driller that action may be necessary to control lost circulation or to prevent a blowout.

Appendix D-4

·, • • pounds per gallon n: a measure of the density of a fluid (as drilling mud).

ppg abbr: pounds per gallon.

pressure n: the force that a fluid {liquid or gas) exerts when it is in some way confined within a vessel, pipe, hole in the ground, and so forth, such as that exerted against the inner wall of a tank or that exerted on the bottom of the wellbore by drilling mud. Pressure is often expressed in terms of force per unit of area, as pounds per square inch (psi).

R

ram n: the closing and sealing component on a blowout preventer. One of three types - blind, pipe, or shear - may be installed in several preventers mounted in a stack on top of the wellbore. Blind rams, when closed, form a seal on a hole that has no drill pipe in it; pipe rams, when closed, seal around the pipe; shear rams cut through drill pipe and then form a seal.

ram blowout preventer n: a blowout preventer that uses rams to seal off pressure on a drillpipe, casing annulus or an open hole. It is also called a ram preventer. See blowout preventer and ram.

reservoir pressure n: the pressure in a reservoir under normal conditions.

s

surface casing n: the first string of steel pipe (after the conductor) that is set in a well, varying in length from a few hundred to several thousand feet.

survey n: a continuous wellbore measurement of a parameter such as pressure or temperature.

T

trip n: the operation of hoisting the drill stem from and returning it to the wellbore. v: shortened form of make a trip.

w

wellbore n: a borehole; the hole drilled by the bit. A wellbore may have casing in it or may be open (i.e., uncased), or a portion of it may be cased and a portion of it may be open. Also called borehole or hole.

wellhead n: the equipment installed at the surface of the wellbore. A wellhead includes such equipment as the casinghead and tubing head. adj: pertaining to the wellhead (as wellhead pressure).

Appendix D-5

Documents

t'f . Q c::;..ktz.d Lt1¢. P~ ,4ctc-..:>k'*'?e.Jl Re.ce:~ Ievols.library.manoa.hawaii.edu/bitstream/handle/10524/33706/1992... · c/o ARCO Oil & Gas 4550 California Avenue Bakersfield,