Geophysical Investigation of Loss of Circulation in borehole drilling

8/17/2019 Geophysical Investigation of Loss of Circulation in borehole drilling

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nterntionl ournl o. !ien!e, e!hnolo"4 nd o!iet4 2015; 3(3): 90-95 91

ele!tri!l resistiit4 #ethod hs proed relible in delinetin"

Fones o. reltiel4 low resistiit4 si"ntor4 o. sturted strt

in rious "eolo"i! terrins (+de$obi, 1999) le!tri!l

resistiit4 #ethod hs been su!!ess.ull4 used !ross ll the

"eolo"i!l terrins in *i"eri nd hs drsti!ll4 ste##ed the

tide o. .ilure in borehole !onstru!tion pro$e!ts (ACo nd

+lorun.e#i, 19'9; +l4inC, 1999; +l4inC nd

+lorun.e#i, 1992)

he dnt"e tht pre G drillin" "eoph4si!s o..er is tht

one is ble to nti!ipte the subsur.!e !ondition nd prepre

deButel4 to sur#ount n4 !hllen"e tht #4 rise durin"

borehole drillin" his ses ti#e nd !ost s when !o#pred

to drillin" blindl4 when one in note sure o. the .or#tion

!hr!teristi!s

he pri#r4 ob$e!ties o. this inesti"tion in!lude:

1 8ondu!tion o. esistiit4 soundin" t the site nd

interprettion o. the .ield >erti!l le!tri!l oundin"

(>) dt to obtin "eoele!tri! pr#eters

2

eter#intion o. the h4dro"eolo"i! !hr!teristi!s o.the subsur.!e t the site bsed on "eoele!tri! nd

ilble "eolo"i! in.or#tion

3 eter#intion o. the "eolo"i!l !on.i"urtion nd

etent o. the horiFon(s) where loss o. !ir!ultion tooC

pl!e

& Ce n pproprite re!o##endtions .or the plnnin"

nd ee!ution o. subseBuent borehole drillin" pro$e!ts

t the site

2% &i"e 'o!a"ion and (es!ri)"ion

he "eoph4si!l eplortion ws !rried out t the site o.two .iled borehole drillin" round the o..i!e blo!C o. the

eprt#ent o. inerl esour!es n"ineerin" nd le!tri!l

n"ineerin" lbortor4 o. the Eederl Pol4te!hni! Au!hi

>erti!l le!tri!l oundin" (> 1) is pproi#tel4

de.ined b4 the "eo"rphi!l !oordintes o. titude * 70 03H

50'HHnd on"itude %0 1%H 2%5HH with n er"e eletion

o. bout 239# boe the #en se leel

Au!hi town is within the An#br h4dro"eolo"i!l sin

he bsin !o#prises n, l#ost, trin"ulr shped

e#b4#ent !oerin" n re o. bout 30,000C#2 t stret!hes

.ro# the re $ust south o. the !on.luen!e o. the ier *i"er

nd enue !ross to res round Au!hi, +Cene, A"bo nd

Asb, west o. the rier, nd An4n"b, dh, *suCC,

+nitsh nd AwC re, est o. the rier Ero# n eletion

o. bout 300#, the du G dh es!rp#ent slopes "entl4

towrds the southwest into the .lood plin o. the ier *i"er

nd !ross, to the west he bsin is drined #inl4 b4 the

An#br rier nd its #in tributries, the #u nd Add

(+..odile, 2002)

Eield obsertions nd desCtop stud4 show tht Au!hi is

underlin b4 "eolo"i! #terils belon"in" to the A$li

.or#tion he .or#tion bers .lse bedded sndstone with

sso!ited !l4 shle interls in the botto# se!tion(e4#ent, 19%&)

he A$li .or#tion is su!!essiel4 underlin b4 #terils

belon"in" to the *suCC nd #u .or#tions he *suCC

.or#tion hitherto !lled the upper !ol #esure, bers

sndstone, shle nd !ol while the underl4in" #u

.or#tion whi!h hs !o#positionl si#ilrit4 with the

*suCC, o..ers hi"her .reBuen!4 o. !ol o!!urren!e


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92 @usu. nus et al : 6eoph4si!l nesti"tion o. oss o. 8ir!ultion in orehole rillin": A 8se tud4 o.Au!hi Pol4te!hni!, Au!hi, do tte, *i"eri

Figure 2. Geological Map of Nigeria Showing The Study Area

our!e:*6A 6eolo"i!l p o. *i"eri 19'& edition e"end

Iu!→ A$li Eor#tion

3% 'os" *ir!ula"ion

Eor drillin" to !o##en!e nd end se#lessl4, the drillin"

.luid #ust be in the ri"ht proportion nd is!ous enou"h to

ensure tht uninterrupted !ir!ultor4 pro!ess is #intined

rillin" .luid !ts s lubri!nt, !ools the bit, re#oes !uttin"

.ro# the botto# o. the hole nd tCes the# to the sur.!e

where the4 !n be stored .or inspe!tion he drillin" #ud is

lso epe!ted to preent loss o. !ir!ultionoss o. !ir!ultion o!!urs when the drillin" .luid

penetrtes the per#eble nd porous .or#tions in the hole

his uto#ti!ll4 brin"s the borehole drillin" to hlt

rillers run into this proble# when proper pre G drillin"

"eoph4si!l/"eolo"i!l inesti"tions re not done his

!hllen"e !n be nti!ipted, be .ull4 prepred .or nd

su!!ess.ull4 hndled with !ler understndin" o. the

spe!i.i! "eolo"4 o. the proposed drillin" site he loss

!ir!ultion belt hs been .ound to o!!ur in li"nites pet4 nd

!rbon!eous shles nd behes s4#ptheti!ll4 with it

(*E+, 200%)

n the stud4 re, boreholes 1 nd 2 were bndoned due to

lost !ir!ultion en!ountered t bout 120.t (3%#) nd 130.t

(39#) respe!tiel4 )

with !hlu#be"er rr4 .or >erti!l le!tri!l oundin"

(> 1), while #odi.ied !hlu#be"er rr4 ws used .or

>erti!l le!tri!l oundin" (> 2) due to sp!e

!onstrints his ws !hieed with the id o. Austrli

ner"4 rCet 8o##ission (A8) soil resistiit4 #eter

nd other .ield !!essories 6eo"rphi!l !oordintes were

obtined .ro# 6lobl Positionin" 4ste# (6P) dei!e

wo erti!l ele!tri!l soundin" (>) were done t thesite usin" !hlu#ber"er rr4 he totl spred len"th (A/2)


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ttined .or >erti!l le!tri!l oundin" (> 1) nd >erti!l

le!tri!l oundin" (> 2) within the li#it o. the ilble

sp!e nd h4dro"eolo"i!l epedien!4 were 200# nd '0#

respe!tiel4 Arti.i!ill4 "enerted ele!tri!l si"nl is Cnown

to penetrte up to A/2 J 1000# (Iere4 nd rooCs, 19'')

erti!l le!tri!l oundin" (> 1) while .our

"eoel!tri! l4ers were resoled .or >erti!l le!tri!l

oundin" (> 2)

5.1. Geoelctric Model for Vertical Electrical Sounding

(Ves 1)

4ers one nd two stnd .or lteriti! topsoil nd sub soil

with thi!Cnesses 171# nd 1057# respe!tiel4 4er three

is the snd4 !l4/!l4e4 snd horiFon he .ourth l4er is the

dr4/resistie snd4 horiFon 4er .ie o. unCnown thi!Cness

is the snd4 !l4/!l4e4 snd l4er >erti!l le!tri!l

oundin" (> 1) is within the i##edite i!init4 o. the.iled borehole 1 he loss o. !ir!ultion within this borehole

o!!urs round the depth o. 120 .t (3%#) he "eoele!tri!

l4er !orrespondin" to the loss Fone is l4er & his l4er is

desi"nted s dr4/resistie horiFon be!use o. its hi"h

resistiit4 lue dell4, loss Fone is epe!ted to be porous

nd per#eble he oids within the soil "rin re epe!ted

to be .illed with .luid whi!h !ould be either ir or wter

Dhen the oid sp!es re .illed with wter whi!h is

!ondu!tie .luid, the resistiit4 o. the horiFon be!o#es low

+n the other hnd, when the oid sp!es re .illed with ir

whi!h is inert, the resistiit4 o. su!h horiFon "oes up

Eor >erti!l le!tri!l oundin" (> 1), we !n s.el4dedu!e tht the loss Fone is per#eble ut with its hi"h

resistiit4 lue, the oid sp!es within the soil l4er in the

horiFon is not !ondu!tie And !onsiderin" tht the depth to

top o. this "eoele!tri! l4er is bout 30#, nd its thi!Cness

bein" 1995#, we !n dedu!e tht the horiFon is n erted

Fone

5.2. Geoelctric Model for Vertical Electrical Sounding

(Ves 2)

he "eoel!tri! #odel .or >erti!l le!tri!l oundin"

(> 2) is o. the s#e trend with >erti!l le!tri!l

oundin" (> 1) he loss Fone here is l4er & heresistiit4 o. this l4er too is er4 hi"h nd it is lso erted

he depth to the top o. this l4er is 3055# he depth to the

bse o. this l4er is unCnown

5.3. Geoelctric Model and Loss of Circulation

he "eoele!tri! #odels "enerted .ro# the interpreted

> dt "ie er4 !!urte pi!ture o. the strti"rphi!l!o#position o. the subsur.!e l4ers where the lost

!ir!ultion o!!urs in the two .iled boreholes his

unders!ores the lidit4 nd relibilit4 o. the ele!tri!l

resistiit4 #ethod in uneilin" the subsur.!e "eolo"4 .

thorou"h "eoph4si!l inesti"tion hs been !rried out

be.ore e#brCin" on drillin" t the site, the .irst two

boreholes would not he been bndoned be!use the loss

Fone would he been dete!ted nd i. the driller is pro.i!ient

enou"h, he would he prepred deButel4 .or the lost

!ir!ultion nd su!!ess.ull4 oer!o#e it nd !o#plete the

drillin" An essentil prt o. the preprtion to oer!o#e loss

!ir!ultion is to use er4 is!ous drillin" #ud to sel o.. the

per#eble prt o. the .or#tion within the loss Fone t ws

lso obious tht there ws no h4dro"eolo"ist superisin" the

drillin" t is hi"h ti#e the so!iet4 Cnew tht borehole drillin"

is not !hildHs pl4 t should be tCen seriousl4 liCe n4

other #$or !onstru!tion worC be!use the eniron#entl

i#p!t o. .iled borehole !n be terri.4in" A .iled

borehole tht is not properl4 seled up !n be the re!eptor o.

point sour!e pollutnt nd !ont#innt tht !n

subseBuentl4 be trns#itted to the entire Bui.er s4ste# o. n

entire re

Figure 3. A !escriptive Geoelectric "og For #es $ Auchi oly


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9& @usu. nus et al : 6eoph4si!l nesti"tion o. oss o. 8ir!ultion in orehole rillin": A 8se tud4 o.Au!hi Pol4te!hni!, Au!hi, do tte, *i"eri

Tale 1. Geographical %oordinates And &levations 'f Sampled oints

&/0 (es!ri)"ionosi"ion Elea"ion

m4'a"i"ude 506 'ongi"ude 5E6

1 > 1 70 03H 50'HH %0 1%H 2%5HH 239

2 > 2 70 03H 525HH %0 1%H 2%'HH 21&

Tale 2a. Geoelectric arameters And Inferred "ithology (#es $)

'a$er

0O

A .E&

5Ohm7m6

hi!8ness

5m6

(e)"h

5m6'i"holog$

1 133 171 171 teriti! topsoil

2 &02 1057 122' nd4 ubsoil

3 %& 17&3 2971nd4 !l4/!l4e4 snd

horiFon

& 3&02 1995 &9%% r4/resistie snd4 l4er

5 110 - -nd4 !l4/!l4e4 snd

l4er

Figure !. A !escriptive Geoelectric "og For #es * Auchi oly

Tale 2. Geoelectric arameters And Inferred "ithology (#es *)

'a$er0O

A .E&5Ohm7m6

hi!8ness5m6

(e)"h5m6

'i"holog$

1 '0 21% 21% teriti! topsoil

2 %2' 120% 1&22 nd4 ubsoil

3 7' 1%33 3055nd4 !l4/!l4e4 snd

horiFon

& 2919 - - r4/resistie snd4 l4er

9% *on!lusions

he results o. the post G drillin" "eoph4si!l inesti"tions

to deter#ine the !use(s) o. lost !ir!ultion in two bortie

boreholes t the Eederl Pol4te!hni! Au!hi, tsCo Desto!l 6oern#ent Are do tte, is presented in this report

) dt

shows tht the loss Fones re per#eble nd erted with

er4 hi"h resistiit4 lues he "eoel!tri! #odels "enerted

.ro# the interpreted resistiit4 dt "rees with the drillerHs

lo"s .or the bortie boreholes

he .indin"s o. this stud4 sere s the bsis .or #Cin" the

.ollowin" !on!lusions:

he .or#tion where the lost !ir!ultion o!!urs is

predo#inntl4 snd4

he .or#tions re per#eble nd porous thereb4

llowin" the drillin" #ud to es!pe inside the#

Althou"h the .or#tions re per#eble nd porous, the

resistiit4 lues re .irl4 hi"h his !n be ttributed

to the .luid within the pore sp!es o. the ro!C/soil

"rins whi!h is #inl4 ir

le!tri!l resistiit4 "eoph4si!l #ethod is er4 use.ul

nd relible in showin" the subsur.!e "eolo"4 nd it

lso helps in identi.4in" the Fone where loss o.!ir!ultion o!!urs s well s wh4 it o!!urs

.e!ommenda"ions

he .ollowin" re!o##endtions he been pro..ered

bsed on the .indin"s o. this stud4:

Pre G drillin" "eoph4si!l inesti"tion should not be

optionl but ne!essit4 .or eer4 borehole drillin"

pro$e!t in order to Cnow the subsur.!e "eolo"4

t should be #de #ndtor4 tht !o#petent

h4dro"eolo"ist should preside oer borehole drillin"

pro$e!t nd lso do!u#ent the entire pro!ess rillin" !ontr!tors who did not .ollow the !!eptble

best pr!ti!es in their $ob ee!ution should be

penliFed

.eferen!es

K1L

ACo nd +lorun.e#i, + (19'9): 6eoele!tri!l sure4.or "roundwter in the *ewer sls o. >o#, Plteu tteournl o. inin" nd 6eol

K2L Iere4, P nd rooCs, (19''): An introdu!tion to6eoph4si!l plortion dition, pp 199

K3L +de$obi, +, (1999): 6eoele!tri! ure4 .or 6roundwteresour!es eelop#ent in Iudns, Idun tte, *i"erie!h disserttion, eprt#ent o. Applied 6eoph4si!s, Eedni +. e!h, ACure Pp 35-3% (unpublished)

K&L +..odile, (19'3): he +!!urren!e nd ploittion o.6roundwter in *i"erin se#ent o!Cs ournl o. inin"nd 6eolo"4 >ol 20, pp 131-1&5

K5L +..odile,(2002):6roundwter stud4 nd deelop#ent in *i"eri Pp 20&-205

K%L +l4inC, A (1990): 8se histories o. #ultiele!trodesresistiit4 pro.ilin" rr4 .or "roundwter in bse#ent!o#ple re o. Iwr tte, *i"eri ournl o. inin" nd

6eol, >ol 2% pp 27-3'


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K7L +l4inC A nd +lorun.e#i, + (1992): eter#intion o."eoele!tri!l !hr!teristi!s in +Cene re nd i#pli!tions.or borehole sitin" ournl o. inin" nd 6eol, >ol 2' pp&03-&12

K'L

e4#ent, A (19%&): eiew o. *i"erin 8ret!euos nd8enoFoi! trti"rph4 our in 6eol >ol 2, no 2, pp %1-'0

K9L *.or,*(200%) : i"nite Mone s n ndi!tor to oss8ir!ultion elt-A !se stud4 o. so#e lo!tions o. An#brtte, outhestern *i"eriAppl !i niron"t>ol10(3) 31-35

Documents

Geophysical Investigation of Loss of Circulation in borehole drilling