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v~Devel.opme@ of=~$p~cial Application)~~Co{~ekl Tubing l$pplied-Plug for Geothermal

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/G. E. Staller, !

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1S. D,./Knudsen

/and A. R. Sattler

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%Sandia Ztional Laboratories /Albuquerque, New M>xico–871 85-and LiverMore, California 94550

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Sandia is a multip~(gram laborato~ operated by Sandia Corporation,a Lockheed Mati)n Company, for the United States Department ofEnergy under Contract DE-AC04-94AL85000.

/Approved fo( public release; further dissemination unlimited.

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Sandia National laboratories

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IssuedbySandiaNationalLaboratories,operatedforthe UnitedStatesDepartmentofEnergyby SandiaCorporation.

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SAND99-261OUnlimited Release

Printed October 1999

DEVELOPMENT OF A SPECIAL APPLICATION COILED TUBING APPLIEDPLUG FOR GEOTHERMAL WELL CASING REMEDIATION

G.E. Staller, S.D. Knudse~ and A.R. SattlerGeothermal Research Department

Sandia National LaboratoriesP.O. BOX 5800

Albuquerque, NM 87185-1033

Abstract

Casing deformation in producing geothermal wells is a common problem in manygeothermal fields, mainly due to the active geologic formations where these wells aretypically located. Repairs to deformed well casings are necessary to keep the wells inproduction and to occasionally enter a well for approved plugging and abandonmentprocedures. The costly alternative to casing remediation is to drill a new well to maintainproduction and/or drill a well to intersect the old well casing below the deformation forabandonment purposes. The U.S. Department of Energy and the Geothermal DrillingOrganization sponsored research and development work at Sandia National Laboratoriesin an effort to reduce these casing remediation expenditures. %ndi~ in cooperation withHalliburton Energy Services, developed a low cos~ bridge-plug-type, packer for use incasing remediation work in geothermal well environments. This report documents thedevelopment and testing of this commercially available petal-basket packer called theSpecial Application Coiled Tubing Applied Plug (SACTAP).

i

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Acknowledgments

The authors would like to acknowledge the contributions of Mr. Jamie Terrell, managerof the Physics and Chemistry Laboratory, Halliburton Energy Services, Fort Worth TXduring the desi~ development and laboratory testing of the SACTAP. We would alsolike to acknowledge the field test support provided by the Halliburton Energy Servicescoiled tubing crews in Midland, TX under the supervision of Mr. Don Rodgers. Finally,the authors are indebted to Mr. Doug Love, Halliburton Energy Services, Midland, TXfor his oversight and leadership during field test operations.

This work was sponsored by the U. S. Department of Energy, Office of GeothermalTechnologies.

ii

TABLE OF CONTENTS

Page

Introduction/Background ........................................................................................ 1

Technical Requirements and Product Smrch ......................................................... 1

Development Testing ................................................................................................3

A.) Development Testing at the Fort Wort~ TX Facility .....................3B.) First Field Test at the Midland, TX Facility ...................................6C.) Modification Tests at the Fort WoII& TX Facility .........................9D.) Second Field Test at the Midland, TX Facility ............................... 10

Conclusion ................................................................................................................ 14

References ................................................................................................................. 15

Appendix A ..............................................................................................................Al

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Introduction/Background

Geothermal wells are commonly drilled in harsh geological formations where geologicactivity is prevalent. Steam and hot water production wells, in this environrnen< areexposed to recurrent geologic activities that often result in formation shear or subsidenceloads being applied to the well casings. These progressive loads often cause the casing,at certain depths, to be deformed severely enough to reduce well production efficiencyand/or restrict or prevent tool access into the well below the affected zones. If the casingis not satisfactorily maintained, worsening deformations can lead to costly well repairs orresult in premature plugging and abandonment of a producing well.

The Unocal Corporatio~ Division of Geothermal& Power Operations, installed andmaintained geothermal production wells at The Geysers Geothermal Field near SantaROSACA. These wells have since been purchased by Calpine Corporation. As a resultof normal inspections on the wells in this field, over 50 have been identified withdeformed well casings. At the request of Unocal, a two-phase Geothermal DrillingOrganization (GDO) proposal was prepared by Unocal and Sandia National Laboratoriesto address the casing deformation and remediation issue. As part ofPhase I ofthisproposal, Sandia was asked to utilize the Drillable Straddle Packe# (DSP) design as abridge plug for casing remediation work. The DSP bridge plug was to be placed in thewell, below the deformation in the casing. This plug was to support a sand and cementplug until the cement properly cured. This DSP/cement plug combination would in turnsupport the drilling fluids used during the casing repair operations. The DSP wasdeveloped by Sandi~ as an inexpensive, high temperature packer for lost circulationtreatment in open hole geothermal wells. Although the DSP met the temperaturerequirements and could expand to fill the casing after passing through the deformatio~some redesign and testing of the protective shroud, the bag packaging technique, and thedeployment procedures was required before the DSP could be used in this type of bridgeplug application.

The work schedule for this project was prepared by Unocal. Their schedule required arapid response to Phase I of the GDO proposal and this left insufficient time for redesignof the DSP. Sandia recommended looking for a commercial packer that could bepurchased off-the-shelf and used immediately or could be quickly modified to meetproject requirements.

Technical Requirements and Product Search

Technical specifications for the bridge plug were prepared by Unocal and Sandia and areas follows:

, 1. Well environment - steam.2. Peak well temperature -450° F.3. Maximum well pressure -200 psi.4. Well flow conditions - shut-in (no flow).5. Casing restriction - minimum I.D. 4.50”.

1

6. Casing specification where plug will be deployed - 11-3/4” (10.88”I.D. X .435” Wall), 54#/f4 Grade K-55 steel. (Note: This will requirea plug expansion ratio of 2.7:1 to pass a 4.00” OD plug through the4.50” ID deformatio~ then fill the 10.88” casing ID.)

7. The plug must support 50’of dry sand followed by a 200’ pour ofcement.

8. The plug should be retrievable or drillable.Based on these requirements, a product search was initiated by Sandia for a suitablepacker.

Prior oil field experience by Sandia stiled to an investigation into the status of theGearhart-Owen Industries, Inc. <GO) Thru-Tubing Bridge Plugs. These plugs could beset in casings on Wireline, through a small aperture or tubing and could support sand andcement to forma casing plug similar to the plug needed for the casing remediation work.However, the GO bridge plugs were produced for use in small diameter (<9-5/8”) casingsand at lower temperatures than those encountered in The Geysers wells. The GO thru-tubing bridge plugs were sold under part numbers 51-5143-00 through 51-5143-08.These plugs are no longer commercially available, however, the inventor of the original00 bridge plug, Mr. Jamie Terrell is employed by Halliburton Energy Services (HIM).Mr. Terrell and HES hold the license to produce and sell the GO bridge plugs. Afterreviewing the technical specifications for the casing remediation bridge plug Mr. Terrell,indicated that with some design changes and proof testing, a suitable plug could beproduced to meet our desi~ requirements and time schedule.

Unocal and Sandia contacted several inflatable packer manufactures in an effort toidenti~ a commercial off-the-shelf inflatable packer for this application. A visit wasmade to TAM International, Inc., HoustoL TX by both Sandia and Unocal staff to reviewinflatable packer designs and discuss packer requirements for casing remediation. Themain limitation to using inflatable packers for this project was the high temperatures thatthe packer elastomer encounters in The Geysers wells. The reliability of the inflatableelements is related to the expansion ratio and peak working temperature. & stated in thetechnical requirements, an expansion ratio of approximately 2.7:1 is needed and at thisratio, combined with a peak well temperature of 450° F, TAM dld not recommend usingtheir inflatable packer for casing remediation. However, a test was arranged by Unocaland TAM to test a new elastomer that could perhaps meet project requirements. This testwas conducted at Schlumberger Inc.’s test laboratory in Sugadand, TX. Test results wereinconclusive and schedule requirements did not permit iiu-ther evaluation and testing ofthe new packer elastomer for use on this project.

A meeting to discuss the casing remediation project and select a packer design was heldby Unocal at their offices in Santa ROW CA on 4/3/98. Attendees included stafffiom%ndi~ Brookhaven National Laboratory, HES, Baker Oil Tools, Calpine, and BillLlvesay, a Sandia consultant. The-modified HES thru-tubing bridge plug was selected asthe best option for a casing plug based on its ability to meet design specifications as wellas project schedules. It was also determined that the most desirable method to deploy thisplug would be on coiled tubing. This would save time and money since dump bailer runs

2

for emplacing the sand and/or cement on the bridge plug could be eliminated. Sandiainitiated a contract with HES, Fort Worth to develop and test a modified thmtubingbridge plug that would meet project requirements. The contract specified that the plugshould be deployed on coiled tubing set in the casing using nitrogen gas, and meet allother specifications previously defined for the casing remediation plug.

Development Testing

A.) Develo~ment Testinz at the Fort Worth. TX FaciliN

The HES facilities in Ft. Worth are used to assemble and test various drilling tools andequipment prior to field use. Jamie Terrell’s facility, at this site, is designed to assembleand test chemical cutter tools. HES has been considering manufacturing and marketingthe old GO bridge plugs through this facility. Mr. Terrell is the primary contact forproduction and sales of these plugs. Our need for a modified GO plug allowed him toutilize both his facility and the local manufacturing contractors to produce and test thecasing remediation bridge plug.

The thru-tubing bridge plug (BP) consists of a collapsible metal petal basket and fourcollapsible centralizer support dogs all attached to a center support shaft. The petalbasket is covered with a high temperature fire retardant material called Nomex. TheNomex cover helps to prevent sand from falling through the voids between the petalbasket petals. The support dogs contain six legs that are deployed by springs that forcethe legs out against the casing wall. When deployed the support dogs secure the BP inthe casing by digging into the casing wall with high strength steel tips on the end of eachof the six legs. The support dog assemblies are positioned so two sets support the BPagainst downwardmovement in the welland two sets preventupward movemen$ seeFigure 1. Likewise,the petal basket isspring loaded to forceit open and out againstthe casing wall whendeployed. A shroud orsleeve around theoutside of the BPretains and protects thedogs and petal basketin their folded/closedposition until theshroud is removed forBP deployment, afterinsertion in a casing.

SupportDogs4 each

NomexCoveredPetal Basket

CenterSuppontShaft

DogDeploymentspMgs4 each

Figure 1-BP Assembly in Opened Configuration

-.. —

Figure 2- Shroud Assembly

To test the shroud/sleeve operatio~ the mechanismwas set up outdoors on a concrete pad. Only theshroud mechanical action (no BP inside the shroud)was tested. To operate the shroud it was comected toa domestic water supply with a garden hose. The waterpressure was used to operate the shroud. Thissimulated shroud operation with coiled tubing andnitrogen gas, but permitted a safer low-pressurehydrostatic test. The shroud assembly is shown inFigure 2. When pressure is applied to the inside of theshroud supportMide tube, a piston that is attached tothe shroud is forced up around the outside of thesupport tube. As the piston and shroud slide up thistube, the BP is uncover~ exposing the dogs thatsecure the center shaft and the petal basket to the

casing wall. The BP would be set in a vertical orientation in a ~ing although theseshroud tests were done in a horizontal position. The shroud mechanism operated asintended and slid along the suppotislide shaft in a steady smooth movement.

?s “. .

FigJIre3- BP Assembly in Casing

A second test was conducted to confirm the operationof the shroud with the BP inside and to test the BP’smechanical strength for supporting sand and cementin a casing. A ten foot length of 11-3/4”, 54#/ft,grade K-55 steel casing was purchased. The casingwas positioned horizontally on two dollies for BPinstallation. The BP was installed in the shroudmechanism and this assembly was then positionedinside the casing as shown in Figure 3. The shroudwas again deployed with domestic water pressure, butbecause the assembly was not centered in the casingduring deployment (it was lying on the bottom of thehorizontal casing), some minor post-deploymentadjustment was required. After adjustment, all fourdogs and the petal basket were verified to be in their

proper position. The casing was then ;Obe positioned vertically for load testing.However, the BP was set near the bottom end of the casing and any movement duringload testing could cause the bottom dogs to slide out of the casing. To prevent this fromoccurring, an additional 12” length of casing was tack welded to the bottom end of thetest casing. Care was required to keep from overheating the bottom BP dogs during thiswelding operation. A.iler this extension was attached to the test casing, the entireassembly (casing with BP inside) was positioned vertically using the test facility bridgecrane and secured to an existing concrete retaining wall, as shown in Figure 4.

To veri~ that the sand load on the BP was acceptable, we poured 200 pounds (-3 ft. ofdepth) of sand directly onto the petal basket. A BP deflection of less than 0.25” was

4

Figure 4 -BP in Test Position

density of cement is -16 #/gal

measured from the top of the casing. Theoretical andpractical experience has shown that after the dry sanddepth exceeds about twice the casing I.D. the majority ofany additional load is bridged by the sand to the casingwall. To verify this, an additional 150 pounds of sandwas placed on the BP. This brought the sand level in thecasing above the top of the BP assembly. To applyadditional down loading on the BP, HES designed a loadframe that could be secured to the casing and used topush or pull the BP. To push from the top, a 10”diameter X 0.5” thick steel plate was placed on top of thesand above the BP. A hydraulic jack was positionedbetween the load flame and the steel plate and a load cellwas placed between the hydraulic jack and the loadframe. A 3“ square tubing column was used to transferthe load between the steel plate and the hydraulic jack. Aphotograph of this setup is shown in Fig&e 5. -

Our requirements calledfor a first pour of up to50’ of cement on top ofthe sand on the BP petalbasket. Since the liquid

or 1 psi per foot of dept~and the cross-sectional area of the casing ID is -93 sq.in., then the 50’ of cement will apply approximately 4650pounds of additional load to the BP.

A peak load of 5000 pounds, as measured with our loadcell, was applied to the top of the sand using the “hydraulic jack. When the load was applied, a total BPdeflection of 0.124” was measured with an indicator gageattached to the base of the hydraulic jack. Knowing thatthe sand bridged the load to the casing wall, a secondload test was conducted to veri$ the maximum load thatcould be applied to the BP without sand. The testassembly was again positioned on the dollies horizontally. The HES load frame wasremoved from the top of the casing and secured to the bottom so the BP could be pulledfrom the bottom side. A yoke was attached to the bottom of the BP center support shaft.A load cell was attached to this yoke and to a hydraulic cylinder used forpulling. Thehydraulic cylinder was in turn attached to the load frame. A photograph of this setup isshown in Figure 6. With the hydraulic cylinder, we applied a tensile load of 6000pounds to the BP with no detectable movement of the BP inside the casing. This is anequivalent load of 64 feet of cement being applied directly to the BP without the sandbridging the load to the casing. A pull test to failure was not done since these loads wereconsidered to be in excess of those expected during casing remediation applications.

5

- . .————

F@Ire 6- PuU Test setup

During testing concerns were raised about pumpingsand through 2“ diameter coiled tubing into a hotgeothermal well. The main fear was that the flowingsand would dry out and bridge off inside the coiledtubing before it could be positioned on the BP petalbasket. It was decided to change the BP recmirements toeliminate pumpingthe sand throughthe coiled tubingand instead apply10’of cementdirectly onto thepetal basket. Afterthis 10’column ofcement hardenedin the casing, anadditional 190’of

cement could then be applied with another coiledtubing run. The State of California requires a 200’plug if a well is to be abandoned. To test the bridgeplug with cement on the petal basket instead ofsan~ several lab tests were conducted. A BP petalbasket with the Nomex cloth bag was deployed in atest casing and cement was poured onto the basket.Only a small amount of cement flowed through thebasket. The cloth covered petal basket should blockand hold the cement for a sufllcient amount of timeto allow a 10’column to harden. To test thiscement-only BP, it was decided to utilize thepreviously deployed BP inside the test casingcontaining the sand. The sand was removed and anadditional section of casing was welded to theoriginal casing to extend its length. This lengthextension was required so a 10’column of cementcould be installed from the BP petal basket to thetop of the casing. As shown in Figure 7, the testcasing was again mounted vertically. Cement waspumped into the top until the casing was fill. Onlya small amount of water was observed below theBP and no cement filtered past the petal basket.Mler the cement cured the casing was positionedhorizontally and cut in half along its len~ asshown in Figure 8. After cutting the casing, it wasnoted that not all of the sand ftom the first test hadbeen removed. However, the small amount of sand

Figure 7- Cement Test Setup

Figure 8- Cement Test Cut Casing

6

left in the casing did not appear to adversely impact these test results and placing thecement dwectly onto the petal basket was approved.

Figure 9a- Air Dolling Test HoIe

Figure 9b - Installing Test Casing

B.) First Field Test at the Midland. TX Facility

A second BP was fabricated by HES for a fill-scalefield test. To confirm BP shroud remova~ enoughpressure had to be applied to the shroud removalpiston so deployment could be documented, with thecoiled tubing rig pressure gages, at the surface. Thebottom end of the BP shroud was equipped withshear pins that were designed to fail when 1200 to1500 psi of nitrogen gas pressure was applied to theshroud removal piston. This pressure should providea large enough pressure spike to be seen from thesutiace, when the BP is set in a well at The Geysers.To test the operation of the BP in an environmentthat modeled atypical Geysers well, the test wasconducted in a 40’ length of 11-3/4”, 54W., steelcasing provided by Unocal. The BP was to be set inthe casing on coiled tubing using nitrogen gas toremove the shroud and deploy the BP. Ten feet ofcement was then to be pumped onto the BP petalbasket again using nitrogen gas to push a wiper andthus the cement through the coiled tubing, asrequired in our specifications. We initially plannedto conduct this test at the HEN Dallas/Fort WorthTechnology Center located near Carrollto~ TX.However, due to our tight schedule and the TechCenter’s prior commitments we were required to findan alternate test site. Doug Love, a HalliburtonCoiled Tubing Technical Specialist from MidlantTX was able to provide a site for this fill scale fieldverification test. The site was located on HESproperty located between Midland and Odess~ TXand provided convenient access for HES trucks andequipment.

A “Rat Hole” drill rig was used to air drill a 38’ deephole on the HES site, and install the 40’ test casing inthe hole, (see Figures 9a& 9b). The test casing hada cone welded to the bottom to guide it in hole and toprevent the casing from being cemented in the hole,if the BP did not properly contain the cement. Aflange was welded to the top of the casing to secure

7

7%.-? . ..--..-—--%s.. . . . . .. ,.,,,--..> . ... . . . . . . - .. —-. — . .

the casing to the stripper on the coiled tubing rig. The BP was unpacked, inspect~ andattached to the coiled tubing crossover fitting. As shown in Figure 10, the BP wasattached to the crossover fitting below the coiled tubing injector and stripper. The BPwas then lowered into the casing and the stripper was attached to the casing flange.Figure 11 shows the final setup for this test bed including the HES coiled tubin~ni~oge~ and cement trucks.

Figure 10- Attaching BP to CoiIed‘hbing Crossover Fitting

Figure 11- Final Setup at Midland, TX

The test was conducted on 9/10/98. The BP wasdeployed in the casing as intended, with nitrogengas. The shroud shear pins broke at 1297 psireleasing the BP. A shear pin failure pressure spikewas recorded on the coiled tubing rig dataacquisition system. The remaining gas in the coiledtubing was then vented to the atmosphere through

the casing and out an exhaust valve on the stripper. This indicated that the shroud wascompletely off the BP since the nitrogen gas could only vent from the coiled tubing inthis manner, if the shroud was pushed completely off and the BP was free inside thecasing. After the coiled tubing was completely vented, enough cement to produce a 10’column in the casing and the wiper was placed inside the coiled tubing. The cement wasthen pushed through the coiled tubing and onto the BP petal basket using nitrogen gaspressure behind the wiper. The wiper did not seat correctly in its catcher, at the end ofthe coiled tubing. Nhrogen gas therefore flowed around the wiper and into the casingagain venting to the atmosphere through the exhaust valve in the stripper. The wiperdesign had to be changed to eliminate this problem and meet our requirements for TheGeysers casing remediation work.

A plot of the HES data taken with the coiled tubing rig data acquisition system duringthis test, is shown below in Figure 12.

8

n

“g 2000aLi? 1000

Geyser Field CT/Bridge Plug-Tagged Botom

A- ,PUH 10 Ft. Iz // /

Set BP -1300psi

f~/PUH

.4-A+ Pump Cement

o 1000 2000 3000 4000Time (seconds)

Test

-----pressure

— depth

Figure 12- HES Data from the First Test at Midland

The cement was allowed to cure overnight. Then the casing was rigge~ pulled out of thehole, and laid down for dissection and inspection. The cone at the bottom of the casingwas torch cut off. Cement was found in the cone indicating a breach of the BP petal

Figure 13- Cutting Casing After Test

basket. Sectioning of the casing as shown inFigure 13, revealed that cement filled thecasing well above the BP and that the BPpetal basket did not support the cement.More than the intended 10’of cement waspumped into the casing, but this is a cementvolume calibration problem and was not thecause of the BP ftilure. We continued to cutapart the casing and removed the BP.Examination of the excavated BP, see Figure14 photograp~ revealed that the petal basketpetals were twisted, ben~ and broken off ofthe BP. The assumption was that theexhausting nitrogen gas from the 1300 psishroud removal operation caused enoughturbulence in the casing to destroy the petalbasket before the cement was pumped.Discussions were held between HES, Unoca.1and Sandia to arrive at a BP designmodification that would eliminate this

problem. The selected solution was to only remove enough of the BP shrou~ with thehigh-pressure nitrogen gas, to release the BP and expose the bottom set of dogs. Thisw“ouldallow the petal basket to remain inside the shroud while the nitrogen gas ventedfrom the coiled tubing. Atler nitrogen venting was complete, the shroud could be pulled

9

.. .-— —. . .———.—

the rest of the way off with the coiled tubing andthus deploy the remainder of the BP. To verifythat this modification would solve the petalbasket problem and to veri~ that the petal basketwould indeed suppoti a 10’column of cement asecond test at Midland was planned.

C.) Modification Tests at the Fort Worth Facility

To veri~ modifications of the BP in thelaboratory, prior to conducting the second field-test, several proof tests were completed at theHIM facility in Ft. Worth. One modification wasto reduce thelength of the BP petal basket andmake it stronger when deployed. To accomplishthis strength increase, the petals were made fromthicker m;terial. Howeve;, this thick material

Figure 15- Petal Basket with Stiffening Bars

Figure 16- Cement Containment Test

Figure 14- BP Recovery After Test

—.. . .deploy properly. The basket was thenassembled from the original thicknessmaterial, but made shorter in length.This new petal basket design operatedsuccessfully in several laboratory prooftests. In addition to modi~lng thepetal baske~ a series of stiffening bars,below the petal basket, were added tothe BP assembly. These bars act asbackup support for the petal baske~ ifthe basket were to fail due to excessiveloading, (see Figure 15).

To again verify the cement holdingcapability of the Nomex cloth coveredpetal basket several leak-through testswere conducted. As shown in Figure16, the Nomex material around thepetal basket held the Class H cementand contained it well enough to preventany leakage through the petal basketpetals. This cement holding proof-testprovided us with confidence that theNomex covered petal basket wouldcontain the 10’column of cement longenough for the cement to begin to

10

Figwre 17- Final Proof Test

setup. Figure 17 shows the finallaboratory proof test veri~ng correctpetal basket deployment with the Nomexcover and backup stiffening bars both inplace.

The shroud support.klide tube wasreduced in length so the shroud wouldonly move up the slide tube about 12”and only uncover the bottom dogassembly. The shroud shear pins wereagain designed to break at 1200 to 1500psi. Operation of this mechanism wasidentical to the previous te~ and did not

require fi.nther proof testing. A “redesigned” BP assembly was prepared by HES for asecond fill-scale field test at Mjdland.

D.) Second Field Test at the Midland. TX Facility

Figure 18- Plange Installation

The new HES BP was assembled in Ft.Worth and shipped to Midland for thesecond test. The same test bed hole usedpreviously was uncovered, inspected andreadied for this test. A second 40’ long 11-3/4” steel casing provided by Unocal andmodified by HES, was delivered to the site.The new casing again contained a cone atthe botto~ but had a threaded collar at thetop. A three-foot length of old casing withthe old flange was salvaged from the firsttest and the casing portion was threaded tomate with the collar on the new casing.Figure 18 shows this flange section beinginstalled on the new casing collar. The newassembly was 43’ long from the bottom ofthe cone to the top of the flange. The casingassembly was then rigged, lifted and placedin the test bed hole, as shown in Figure 19,using the hoist on the coiled tubing rig.

The second test was conducted on 10/14/98.The new BP was assembled for attachmentto the coiled tubing. The redesigned shorter

shroud slide tube is shown in Figure 20. The BP was attached to the wiper catcher/posttest clean out assembly that was in turn connected to the end of the coiled tubing. Thisassembly was lowered into the test casing and the flanges were secured. The BP was run

11

-. ., —. —...— .. . — —.—

in

Figure 20- Shroud with Short Support/Slide Tube

he casing to tag the cone at the bottom. Thebottom win-tagged at 32’ as noted on the coiledtubing rig dep;hindicator. The BP was then pulledup 10 feet to position it for the test. Nitrogen gaswas pumped into the BP shroud piston through thecoiled tubing. The shear pins broke atapproximately 1300 psi and the nitrogen vented

horn the coiled tubing through the casing as intended. This operation set the bottom dogassembly and the coiled tubing was then-pulled up to expose the remaining dogs andthe petal basket. The shroud was to be pulledup f= enough to break a small wire rope cableattached to the top of the BP and to the bottomof the shroud assembly. This breakaway cablewas to provide a weight indication signal onthe coiled tubing rig weight indicator, to showthat the shroud had been pulled up f~ enoughto completely set the BP. No indication of the1000-pound load from the breakaway cablewas observed on the weight indicator loadcell. After pulling up about 11’,it wasdecided that the shroud was off the BP andcement pumping could begin.

Approximately 1.25 bbl of cement (theamount calculated to produce a 10’column ofcement in this casing) was pumped into thecoiled tubing and the wiper was insertedbehind the cement. The coiled tubing behindthe wiper was then pressurized with nitrogen

Figwe 21- Shroud Post Test Removal

12

gas to push the cement through the coiled tubing and onto the BP. The cement waspushed with the wiper as intended and after the wiper seated in the catcher assembly thenitrogen was vented from the coiled tubing at the nitrogen truck. The coiled tubing waspulled up to a zero depth indication and the flange bolts were removed. The shroud wasthen lifted out of the test bed, as shown in Figure 21 above, washed and removed fromthe wiper catcher assembly. The wiper was then pressurized agai~ this time to 1900 psito open the clean out ports on the catcher assembly, so the inside of the coiled tubingcould be flushed with water and cleaned.

A plot of the HES data recorded during this te~ with the coiled tubing rig dataacquisition syste~ is shown in Figure 22.

Sian&a I Unocsl Thru-Tubing Bridge Plug Tests2nd Test in Midland, TX for The Geysefs Fid, CA

I Nata Wai@tindicatorReadingMaskad~ No”=(alacbicsl?ortipparffiction?)-mo 1 -5

-Time a-. 930am140CT98 Tkne(minubs)

Figure 22- HES Data from the Second Test at Midland

The cement in the casing was viewed from the surface and measured to be 22’-5” fromthe casing flange to the top of the cement. This was where it was expected to be if weactually pumped 10’of cement onto the BP petal basket. We waited overnight for thecement to filly cure. The casing test bed was again rigged and lifted from the hole andpositioned on the ground for sectioning. The bottom cone was then cut off the casing asshown below in Figure 23. No cement was visible in the casing and less than one gallonof diluted cement that filtered through or around the petal basket was visible in the cone.The casing was then cut to expose the deployed BP and cement plug. Figure 24 showsthe BP with the 10’cement plug in position in the sectioned casing. This test wasconsidered a success, except for the breakaway cable proble~ and everything fi.mctioned

13

.. —. —.. —. ——.———,.

Figure 23- Cutting Cone

as intended. The test alsodemonstrated that the BP petalbasket could support a 10’column ofcement. To determine why thebreakaway cable failure was notdetected on the coiled tubing rig loadindicator, the BP was removed fromthe test bed. The cement wasremoved from the top of the BP toexpose the breakaway cable. Thecable appeared to have pulled out ofits chimp on the shroud assemblyinstead of breaking, see Figure 25.This cable attachment design wouldhave to be changed on fbture BPassemblies to insure that the cable

will break before pullout can occur. The entire BP assembly was then packaged andreturned to the I%S Ft. Worth facility for additional post test analysis.

Figure 24- Sectioned Casing Figure 25- Break Cable Recovery

14

Conclusion

Through a rapid development and testing progrq a HES thru-tubing BP has beenmodified, tested and certified for use in geothermal well casing remediation applicationsat The Geysers geothermal field. This BP has been named the Special ApplicationCoiled Tubing Applied Plug (SACTAP). The SACTAP meets or exceeds the technicalrequirements for this application and can be deployed on coiled tubing and set in a 450° Fsteam filled, non-flowing well casing using nitrogen gas. Test results show that up toten feet of wet cement can safely be placed directly on the SACTAP petal basket. Afterthis initial 10’column of cement cures, calculations and field experience shod that anadditional 20’ of sand and/or up to 190’of wet cement can safelybe added to theSACTAP to complete the plug and secure the well for casing remediation work or wellabandonment. After casing remediation work is complet~ the SACTAP can be drilledover, to cut the tips off the support legs on the dogs, and removed. Using the basic GOthru-tubing BP desi~ SACTAP’s can be readily modifie~ by HES, to accommodatevarious size casings and could again be adapted for deployment on a wireline, ifnecessary.

A SACTAP based on this design was procured by Sandia and used, by Unocal, duringcasing reme&ation work at The Geysers. The SACTAP fimctioned as intended duringthis operatio~ although other problems resulted in failure of the actual casingremediation work4. Future casing remediation efforts that require a bridge plug formilling or other operations can utilize this technology.

The 11-3/4”, 54#/ft steel casing SACTAP has a maximum outside diameter of 3.75” priorto deployment, is 110” long and weighs approximately 200 pounds. A HES drawing ofthe SACTAP is provided in Appendix A. SACTAP bridge plugs can be purchaseddirectly horn HES. The HES contact for procurement is Mr. Jamie Terrell, Manager,Chemical/Physics Laboratory, Halliburton Energy Services, 1100 Everman Parkway,Fort Wo@ TX 76101-1936. A six to eight week lead-time is required for fabricatio~assembly and delivery of a SACTAP.

15

.,,-.. ?..,. ,e.,. H,. --m .-— —.,= —— —.. —

References

1. GDO Project - ‘Geysers Deformed Casing Remediation”, Proposed Friday 04/03/98by Baljit Sing~ Unocal Corporation and AllarI R. Sattler, Sandia NationalLaboratories.

2. G.E. Staller, D.A. Glowk~ J. GabaldoL P. Gronewal~ S.D. KnudseL D.W.11.aymon~ J.J. Westmoreland, G.L. Whitlow, J.L. Wke, and E.K. Wright, 1999“Desi~ Development and Testing of a Drillable Straddle Packer for LostCumulation Control in Geothermal Drilling,” Sandia Report, SXND99-0819, SandiaNational Laboratories, Albuquerque, ~ 87185-1033.

3. Technical data sheet “Determination of Minimum Plug Length” High PressureIntegrity, Inc., 1204 Distributors Row, Harahaq LA 70123, reference intemethttp:/Avww.hpitools.comhdex3.ht~ technical dat~ plug leng@ and HESinstructions for the Dump Bailer Cement Kit, see section on “Recommended PlugLength”.

4. Steve Furry 1999 “The Dog Leg Reamer/Casing Patch Project,” GDO Report,Geothermal and Power Operations, Unocal Corporatio~ Santa ROSZCA 95401

16

PRIOR TODEPLOYMENT DEPLDYED

!92TUBE <7. FT)

I

DUG6 ARMS

DOGS6 ARMS

NEIMEX COVEREDPETAL BASKET

DOG6 ARMS

HES - SACTAP

BRIDGE PLUG

FOR 11-3/4 CASING

Al

APS TECHNOLOGYBill Turner, Managing Director800 Corporate RowCromwell, CT 06416

BALLEW TOOL COMPANYLeon D. BallewP.O. BOX 361Cobb, CA 95426

BAKER HUGHES INTEQNic Nickels2050 W. Steele Lane, Suite C-1Santa ROSZCA 95403

BAROID DRILLING FLUIDS, INC.Gene PolkManager, Customer Service2220 First Street, NWAlbuquerque, NM 87102-1041

BOART LONGYEAR COMPANYRoger MageeP.O. Box 1000Dayton, NV 89403

BOART LONGYEAR COMPANYJohn Mastor, General ManagerContracting ServicesP.O. BOX 27314Salt Lake City, Utah 84127-0314

BOART LONGYEAR COMPANYPatrick “Paddy” J. LanganProduct ManagerP O Box27314Salt Lake City, Utah 84127-0314

CALENERGYAlex Schriener, Jr.950 W. Lindsey RoadCalipatria, CA 92233

CALENERGYDon Condie950 W. Lindsey RoadCalipatri~ CA 92233

cALPrlw CORPORATION

Marc Steffen10350 Socrates Mine RoadMiddletown, CA 95461

CAITHNESS RESOURCES, INC.Gordon G. Gollan6111 Kelso Valley RoadWeldon, CA 93283

COSO OPERATING CO.John Gastineau900 N. Heritage Dr., Bldg. DRidgecres~ CA 93555

WILLIAM D’OLIERGeothermal Energy Consultant310 Hume LaneBakersfiel~ CA 93309-2427

DOWELL SCHLUMBERGERBob Fagan, WCSLaboratory Manager, Western Division6090 Greenwood Plaza Blvd.Englewood, CO 80111 “

DOWELL SCHLUMBERGERBud FrederickEngineering & Marketing ManagerP O BOX81437

DOWELL SCHLUMBERGERRon WilsonCement Cell LeaderP O BOX81437Bakersfield, CA 93380-1437

1

,;!. ,.- P,-.-,.--x—mm- -..+... .,7..--}.. a,...,,..,,,..,- -m .. . - .-..:.-... ,,.. . .———-. ..___..

DRILL COOL SYSTEMS, INC.Elwood ChampnessTom Champness627 Willkuns StreetBakersfield, CA 93305

ENP CAPITAL RESOURCES, INC.David A. Glowk~ Director811 Sussex DriveAust~ TX 78745

EPOCH WELLSITE SERVICES, INC.Steve Appleton5880 District Blvd. #10Bakersfield, CA 93313

E V I OIL TOOLSMcALLISTERBob JohnsonP O BOX 1824Palm Springs, CA 92263

E V I WEATHERFORDJoe Turk1000 Church RoadRio Vista, CA 94571

E V I WEATHERFORDTom Bailey515 Post Oak Blvd.Houston, TX 77027

GEO HILLS ASSOCIATESJames B. Combs2395 Catamaran DriveReno, NV 89509-5731

GEOTHERMAL DEVELOPMENTASSOCIATESG. Martin Booth 111251 Ralston StreetReno, NV 89503

GEOTHERMAL RESOURCE GROUPBill RickardPO BOX 1189840201 Sagewood DrivePalm Desert, CA 92255

GEOTHERMEX, INC.James W. LovekinManager of Field Operations5221 Central Avenue, Suite 201Richmond, CA 94804

GWB CONSULTANTSGary W. Batcheller704 Sage Brush RoadYukon, OK 73099

HALLIBURTON ENERGY SERVICESJamie Terrell, Manager, Chemistry Lab1100 Everman ParkwayFort Worth, TX 76140

HALLIBURTON ENERGY SERVICESDoug Love, Coil Tubing Tech Specialist4000 N. Big SpringMidland, TX 79705

HALLIBURTON ENERGY SERVICESDon Rogers, Team CoordinatorP.O. BOX3746Odess% TX 79760-3746

HALLIBURTON ENERGY SERVICESJohn MesserschmidtField Technical AdvisorPO BOX80118Bakersfield, CA 93380-0118

J&R ENERGY ASSOCIATES, INC.Nyla Jones1514 Lupine RoadHealdsburg, CA 95448

2

LAYNE CHRISTENSEN CORP.Brian EdwardsP.O. Box 3077Salt Lake City, UT 84130-0777

PAJARITO ENTERPRISESJohn Rowley

3 Jemez LaneLOSAkUllOS,NM 87544

LIVESAY CONSULTANTS, INC.

Bill Livesay126 Countrywood LaneEncinitas, CA 92024

SMITH DRILLING AND COMPLETIONS

Mike Florence3101 Steam CourtBakersfield, CA 93308

M-I DRILLING FLUIDS CO.Tom Heinz6301 Seven Seas AvenueBakersfield, CA 93308

SMITH INTERNA’HONAL, INC.John CampbellP O Box 60068Houstoq TX 77032

NABORS DRILLING USA, INC.Ron Cleveland3919 Rosedale HighwayBakersfield, CA 93308

SOUTHERN METHODIST UNIVERSITYDavid D. BlackWellDepartment of Geological SciencesDallas, TX 75275

NADET INSTITUTEPeter H. Smeallie600 Woodland TerraceAlexandria VA 22302

NOVATEKDavid S. Pixton2185 South Larsen PkwyProvo, UT 84606

OCEAN DRILLING PROGRAMEugene C. Pollard, Jr.Operations SuperintendentTexas A&M Univers@ Research Park1000 Discovery DriveCollege Station, TX 77840

OXBOW POWER SERVICES, lNC.Walter R. (Dick) BenoitResource Manager9790 Gateway Drive, Suite 220Reno, NV 89511

STATE OF CALIFORNIACALIFORNIA ENERGY COMMISSIONPablo GutierrezEnergy Technology Development DivisionResearch and Development Office1516 9* Street MS-43Sacramento, CA 95814-5512

THERMASOURCE, INC.Louis E. Capuano, Jr.P.O. BOX 1236Santa ROSZ CA 95402

THERMASOURCE, INC.Jim HansonP.O. BOX1236Santa ROS~ CA 95402

TONTO DRILLING SERVICES, INC.Larry Pisto2200 South 4000 WestSalt Lake City, UT 84126

TONTO DRILLING SERVICES, INC.Nguyen Do2200 South 4000 WestSalt Lake City, UT 84126

TMNS PACIFIC GEOTHERMALTsvi Mekkw111 Broadway, Suite 300Oakland, CA 94607

TWO-PHASE ENGINEERINGAND RESEARCH, INC.Douglas Jung, P.E.3209 Franz Valley RoadSanta Ros~ CA 95404

UNIVERSITY OF UTAHEnergy & Geoscience InstituteDennis L. Nielson, Ph.D.Department of Civil andEnvironmental Engineering423 Wakara Way, Suite 300Salt Lake City, UT 84108

UNOCAL GEOTHERMALSteve Furry1300 North Dutton AvenueSanta ROSZ CA 95401

UNOCAL GEOTHERMALRodney Bray1300 North Dutton AvenueSanta ROSZ CA 95401

UNOCAL CORPOIUTIONMichael E. Utt, P.E.Technology & Operations Support14141 Southwest FreewaySugar Land, Texas 77478-3435

U.S. DEPARTMENT OF ENERGYAllan JelacicGeothermal Division, EE-121000 Independence Avenue SWWashington, DC 20585

U.S. DEPARTMENT OF ENERGYLew W. PratschOffice of Geothermal Technologies, EE-121000 Independence Avenue, SWWashington, DC 20585

U.S. DEPARTMENT OF ENERGYMarshall J. Reed, Program ManagerGeothermal Reservoir TechnologyOffice of Geothermal Technologies, EE-121000 Independence Avenue, SWWashington, DC 20585

Internal Distribution:

MS-0706 J.K.Linn(6113)MS-1033 M. R. Prairie (6211)MS-1033 S. D. Knudsen (6211) 10 copiesMS-1033 G. E. Staller (6211) 10 copiesMS-1033 A. R. Sattler (6211) 5 copiesMS-9018 Central Technical Files, 8940-2MS-0899 Technical Library, (491 6)2 copiesMS-0612 Review & Approval Desk, (4912)

for DOE/OSTI

U.S. DEPARTMENT OF ENERGYPaul GrabowskiOffice of Geothermal Technologies, EE-121000 Independence Avenue, SWWashington, DC 20585

4