19656-Reservoir Description and Performance Analysis of a Ma

7/24/2019 19656-Reservoir Description and Performance Analysis of a Ma

1/16

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,

SPE 19656

Reser~oir Description and Performance Analvsis of a Mature

S

=- tuorF% - unmmErms

Miscible Flood in Rainbow Field, Canada

D, E. Bi l ozi rnd P,M Frydl ,Mobi l Gi l Canada

r

A

Copyright1SS9,Societyof PetroleumEngineers, Inc.

Thispaper weapreparedfor preaentalionat theS4thAnnualTechnicalConferenceand Exhibitionofthe Societyof PetroleumEngineereheld In San Antonio,TX, Octcber S-1 1, 19S

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ae preearrtad,have notbean reviewedby theSocietyof Petroleum Engkrearaand aw subjectto correctionby the author(a).The material, aa preeented,doesnotneceeeerily retfe

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.4BsIlUI

producti onmethods (reve?seconi ng, gas cycl i ngan

hori zontal wel1 applicati on) .for di f ferent part s o

The Rai nbow Keg Ri ver AA pool i s a dol omt i zed

the pool ,

carbonatereservoi r i n a mature sta e of a verti cal

?

ydrocarbonmsci bl e f l ood. Tba ong hi story of

MUU &LM

enhancedrecovery, pl us the fact that the pool had

not produced accordi ng to i ni ti al ex pectatons,

Thi s study i l l ustratesthe newengi neeri ngparadi g

f ormed an i deal fr amework for an i nterdi sci pl i nary

and the appl i cat i onof

(~festi gati v geol ogi cal an

re- eval uati on ; : e theres~tl

and i t s depl et i on

engi neeri ng techl ~i ques .

Art i cl es documenti

mechani sms.

p~n; i ded

verti calw~tdrocarbonmsci e fl aods have typ a

i nterpretati on

of the pool

al l ow~d %

dqalt

$)

t i

i ni t i ati on )3),

devel opmentof an opti mzeddepl eti onstrategybased

perf ormance *7 ,

moni ; ori *~~$*~

expansi on(e) , si mul a i

on mni mzi ngconi ng and maxi mzi ngrecovery i n the termnati on (due to poor perf ormance)1 o~ th

remai ni ngoi l sandw ch.

f l oods. No speci f i cdocumentat i oncoul d be foundo

managi ng a mature vert i cal hydrocarbon msci bl

Acqui si ti onof 3- D sei smc data provi ded a better

f l ood where the remai ni ng oi l bank i s rel ati ve

def i ni t i onof the shape and si ze of the reservoi r

thi nand sandw chedbetweenthe sol vent bank and th

and l ed to the dr i l l i ngof four f l ank wel l s. The

ori gi nai oi l -water contact. Thi s paper di scuss

3-D sei smcdata, i nf ormati onf romthenewwel l s and

themanagementof thi s type of maturemsci bl ef l oo

r ei nt erpret at i on of ol d wel l s resul t ed i n a

i n the Rai nbowKeg Ri ver AA pool .

reassessmentof pool vol umetr i c. A newgeol ogi cal

model suggestedthe presenceof unswept oi l , whi ch

The Rai nbowKeg Ri ver AA pool i s l ocated i n th

was l ater substant i ated when one wel l

was

nort h-westerncorner of Al bert a, Canada, about 96

recompl eted above the sol vent/ oi l contact and

L l ometers (600 ml es) south of the Arcti c Ci rcl e

~ro:ced oi l whi ch had been bypassedby the soi vent

I t was di scovered i n Apr i l 1967 and pr imar

In combi nati on w th a revi sed materi al

bal an; e and a ravi ew of msci bi l i t y, t he new

producti onresul tedi n a pressuredecl i nebel owth

bubbl e poi nt pressure w thi n one year. I n Apri

reservoi r i nterpretat i onexpl ai nedpast erf ormance

B

1969, a gas i nj ecti on scheme was i mpl ementedan

and demonstratedthe successof themsci l e f l ood.

; : ; ; r i nj ecti oni nto the aqui fer commencedi n Apri

After the reservoi r descripti on ad performance

anal ysi swere compl eted, the maj or chal l engewas to

Si nce August 1972, the Keg Ri ver AA pool has bee

devel op a producti on strategywhi ch opti mzed the

under a verti cal hydrocarbonmsci bl e fl ood, Th

oi l recovery f romthe remai ni ng15-metr eoi l bank.

f l oodconsi sts of i nj ecti nga sol vent composedof

The mai n obj ecti veof the str i ttegywas to reducethe

m+ni mumof 45 mol e percent ethane-pl usi nto the ape

sandw ch l oss.

Usi ng xyl ene washes, si gni fi cant

i ncreases i n the producti vi ty i ndex were achi eved

of the reservoi rand forci ngthe sol vent downwardt

msci bl ydi spl acethe oi l bei ng prodccedf rombel o

w thout l arge i ncr eases i n gas product i on. A the sol vent - oi l cont act ( Fi gure 1) , The i ni t i a

simpl i fi ed coni ng

si mul ati on model provi ded a

total recovery factor usi ng thi s enhanced oi

qual i tati vevi ewof how the maj or reservoi r f aci es

af fectedcone devel opment, The model pl us reservoi r

recoverymethodWS esti matedto be 85 percent,

descri pti on l ed to recommendati ons of opti mum

In 1986, the Rai nbowKeg Ri ver AA msci bl e fl oo

appearedto be i n j eopardy,

The oi l producti onwa

Referencesand f i guresat end of paper,

decl i ni ngrapi dl yand the produci nggas-oi l rati o

289


2/16

RESERVOI RDESCRI PTI ONANDPERFORMANCEANALYSI SOF

2

A NATUREMSCI BLEFLOODI NRAI NBOWFI ELD, CANADA

sp~1965

.

w?.: abnormal l yhi gh. I n addi ti on, the dctual oi l

producti onf romthe pool had typi cal1y bem about 70

f

the rate ori gi nal l y predi cted (Fi me

7

e f fn 2% Based on t he ori : , i naloi l - i n- paCe

2)~$

esti mateof i 5 9

$106 m3 and

an esti matedrecovery

of 12. 5x 10~ m ,

the pool had onl y produced

one-hal f of i ts expected recovery, and yet there

were i ndi cati ons that the remai ni ng ~11 bank was

qui te thi n.

The i ntegrati on of geol ogi cal and engi neeri ng

anal y;esprovi dedthe opportuni tyto:

.

Redefi ne the reservoi r, the associ ated

vol umetri c and i denti fy bypassedoi l i n

the sol vent- sweptzone.

2.

Anal yze the basi c dat a provi ded by

previ ousstudi es.

3.

Anal yze the current

msci bl e

f l ood

perf ormance.

4.

; ; ; odthe new reservoi r descri pti on and

per f ormance to

provi de

recommendati onson how to opti mze the

remai ni ng proti ucti onpotenti al I n the

pool.

Ful l understandi ngof the AA msci bl ef l ood and i ts

opti mzati on

has two i mportant ramf i cat i cms.

Fi rst. several mscl bl e fl oods i n the Rai nbowfi el d

are approachi ngmaturi ty and are devel opi nga thi n

oi l bankw th sol vent above the oi l and the ori gi nal

oi l -water

contact bel ow

The ef f i ci ency of

depl et ing thi s oi l sandw ch i n the AA pool may

serve as a standard for the other msci bl e fl oods.

Secondl y, i f the msci bl e fl ood mechani smand the

geol ogy i s ful l y understoodi n the AA pool , future

f l oods fn Rai nbowcan be desi gned and i mpl emented

w th l ess ri sk and greater conf i dence.

SEOLOGY

(a) Reservoi rDescri pti on

The

AA pool i s one of

more

than 80

hydrocarbon-beari ng carbonate bui l dups i n the

Rai nbowFi el d.

The bui l dupsdevel opedapproxi matel y

3P0 ml l i on years ago i n the nnrthwesterrfpart of

the Mddl e Devoni anEl k Poi nt Basi n. The El k Poi nt

Basi nwas occupi edby a shal l owtropi cal sea whi ch

coveredmost of the provi nceof Al bert aand extended

as far south as North Dakota. At the northwestern

edge of the sea,

an extensi ve barr ier reef

(Presqu i l e)devel oped,

The barr i er reef control l ed

the i nfl owof f reshmari newater i nto the basin and

periodi c restr ict ions l ead to devel opment of

evaporl ti c condi ti ons,

Cfowth of the numerous

smal l er carbonatebui l dups, whi ; ~edevel oped i n the

Rai nbow

sub-basi n behi nd

barr ier , was

:;MN4L

i nterrupted by these hi gh sal i ni ty

Tho AA pool i s a carbonatebui l dupcoveri ngan area

of approxi matel y one square ml e and reachi ng

el evatt , onf nearl y 165metres abovethe surr oundi ng

off - reef carbonate sed{ments (Fi gure 3).

The

bul l dup sedi ments are compl etel ydol omti seal . The

t~mngand dol omtl zati onof the AA pool as wel l as

the other Ratnbowreservoi rs ha

(

ot been cl earl y

establ i shed.

Schmdt et al 141 f v,r earl y

dol omti zati on,whi l e Ql ng and Mountj oy

h$

1ater dol omtl zatl on duri ng i ntermedlate ~~ ~?

Al though dol omtl zati on compl etel y destroyed the

ori gi nal sedi ment f abri c on the mcroscopi c l evel ,

f ai r preservatl o~h~f sedi mentary ; ~[i $ures a

bi ocl asts on

masoscopi c

al l ow

recogni ti m of numerous sedi mentaryfacl eq and. t

devel opment of a deposi ti onal model of, ,the

bui l dup.

The tr ansformati onof the deposi ti onal model i nto

reservgi r model i nv~l vedseveral steps.

Di f ferm

faci eswere characteri zedby a range of porosi tya

permeabi l i ty val ues,

types

of porosi t y,

a

var iat i ons i n cont i nui ty of pc?ous uni ts.

T

faci eswere then grouped i nto l arger uni ts based

the envi ronment of deposi ti on. . Because each

these l arger uni ts was domnated by one or t

sedi mentary f aci es,

i t was rel ated to a set

reservoi r propert i esand provi dedthe f i nal step

transl ate the deposi ti onal model i nto a reservo

model .

The deposi ti onal envi ronments i denti fi ed I n t

reservoi r descri pti on are

shown in Figure

Al thougheach deposi ti onal envi ronment has p?ovl d

an i mportant cl ue i n understandi ngthe msci b

f l oodperf ormance, the most i nf l uenti al faci eswe

ths exposuresurf aces.

There wa$ stwmg evi dencethat the growth of the A

bui l dup was 1nterruptedat 1east two ti mes duri

per i ods of l owered sea l evel and caused t

devel opment of exposure surf aces.

The exposu

sedi ments are characteri zed by extremel y l

porosi tyand permeabi l i ty. Becauseof thei r ori g

dur ing bui l dup exposure, they form thi n bu

l ateral l yextensi veuni ts whi chcan be correl atedi

cor es and on l ogs through a l arge par t of t

bui l dup.

(b) Vol umetri c

Sei smc i sochronmappi ng pl ayed a l eadi ng rol e i

expl orati onand earl y devel opment dri l l i ng i n th

Rai nbowFi el d. The methodrel i ed on detecti ngthe

anomal i esi n the i ntwval


3/16

.

SF5 19656

DI ANEE. BI LOZI R, PAUL MFRfDL

3

I l l ustratedi n Fi gure 5 where unswept oi l exi sts

perchedon anhydri tehori zonsnear the peri hl eterof

the pool .

Uhen theAA pool was revi ewedusi ngthi s concept, i t

becam apparent that 3 exi sti ngwel l s penetratedthe

reservoi r i n a posit i onanal ogoust o the far ri ght

wel l i n Fi gure 5.

Re- eval uati onof the open hol e

l ogs of one of thesewel l s suggestedthe presenceof

unswept oi l near the topof the reservoi rhi gh above

the sol vent- oi l contact.

Comp: ;i sonof the densi ty

and neutronporosi ty l ogs (Fi gure5) shows that the

two curves overl ap fr om1618 to 1640 metres, are

separatef rom1650 to 1683metres, and overl apagai n

f rom168s to 1726 metr es.

The curves.separate i n

the sol vent- sweptzone becausethe neutronporosi ty

; ; ~ve~sponse i s su[; pressedi n the presence of

The wel l was i ni ti al l y perforatedbel ow

the sol ; ent- oi l ccntact at 1683 metr es and produced

cl ean oi l for two years unti l sol vent breakthrough.

However, i n 1988, the wel l was re-~erf oratedabove

t he anhydri t e i n t he upper zone where the

overl appi ng l ogs had suggested the absence of

sol vent. Thi s i nterpretati on was subsequentl y

confi rmedby the producti onof cl ean oi l fr omthi s

upper i ntervhl .

I EHOF PREVI OUSSTUOW

(a) Revi ewof Aqui fer Stze

The eval uati onof the aqui fer si ze i n 1969was very

si ml i sti c as there were onl y f i ve wel l s i n the AA

oo . Usi ng the cyl I ndr ical- type concept of the

reef, the aqui fer was assumed to exi st under the

oi l - beari ngKeg Ri ver AA reef onl y, w th the edges

: ;s:; ; . ~ff j fer

descri bedby the sl opes of the reef

. Thi s resl ted i n a very smal l aqutfer

of 14 x 106 m3 whi ch provi dedvery l i mtedpressure

support .

Addi ti onal dri l li ng i n the Rai nbowfi el d si nce 1969

has al l oweda much broader perspecti veon the si ze

of the aqui fer.

Several wel1s, whi ch were dri 11ed

and abandonednear the AA pool , were eval uated for

water- beari ngzones occurr i ngat the same depth as

the aqui f er i n theAA pool and provi dedan extensi on

of the AA pool aqui fer,

hs ew otenti a a~l i f r

si zewas vol umetri cal l yesti matedto be 59 x 10 m .

(b) Revi ewof Materi al Balante

The numerous materi al bal anc c c

[ l 2, 1\ J ti ~~~c$~a~~

thi s pool from1968 to 1972 11)

on the peri od of t i me f rom the start of oi l

producti on(May 1967) to the start of gas i nj ecti on

23 months ater,

The pressure responseduri ng thi s

ti me peri odwas stri ctl ydue to f l ui dproducti onand

water i nf l ux, thus simpl i f yi ngthe materi al bal ance

cal cul ati onto sol ve for the ori gi nal oi l - i n- l ace,

8 the

Gi ven a l i mtedaqui f er si ze of 14 x 106 m,

materi al bal ance cal cul ati onsconsi stent l yresul ted

i n ori gi nal

3

o l - i n- pl ace est imat e of

approxi matel y16 x 106m ,

Usi ng the new reservoi r vol umetri c and a l arger

aqui fer, the materi al bal ance cal cul ati onf or the

same peri od of ti me was revi ewed an provi ded an

$

ori gi nal oi l - i n- pl aceof

11 x 106 m .

A sampl e

cal cul ati onts provi ded+3 Appendi xA.

The water i nfl ux vol umes frcm the new materi al

bal ancecal cul ati onswere tested by two methods to

determnethei r val i di ty.

The graphof water i nf l ux

versus ti me (Fi gure 6) i ndi cated that no water

i nf l uxoccurredunti l f our months af ter producti on

The l ack of earl y water i nfl ux i s reasonabl egi ven

that a thresha~d pressure drop had to be reached

before the ~nf l uence of the aqui f er could be

measured.

The water i nfl ux i ncreased duri ng the

next tour months unti l the bubbl epoi nt pressurewas

rzachzd.

At that poi nt ,

the rate of the water

i nf l ux stabi l i zed, whi ch woul d be expscted b~cause

the expansi onof the gas cap then becomes the mai n

dri vi ngf orce.

The second test f or t he val i di t y of t he i nf l ux

vol umes was to use the stabi l i zed water i

~di $at c ~

vol ume to esti mate the potenti al aqui fer si ze .

The cal cul at i on, shown i n Appendi x B,

aqui fer si ze of approxi matel y60 x 10 m.

Thi s

matched the aqui fer si ze of 59 x 106m3 determned

vol umetri cal l y.

(c) Revi ewof Hi sci bi1i ty

The Rai nbowKeg Ri verAA pool was an i deal candi date

for a ver ti cal mscibl e f l ood.

By 1969 i t was

conceptual i zedthat the pool woul d i ni ti al l y be

fl oodedw th a sl ug of enri chedgas above the oi l ,

fol l owedby i nj ecti onof a l ean natural gas. The

oi l woul d be msci bl y di spl aced downward by the

enri ched gas (sol vent) , whi ch woul d be i n turn

msci bl y di spl aced downward by l ean gas.

oi l

producti onwoul d be taken f rombel owthe sol vent- oi l

contact.

Di spl acement woul d be I , l aximzedecause

the downwardmovement woul d perm t favorabl egravi ty

stabi l i zat i onef fects.

The AA pool msci bl ef l oodwas desi gned, there ,

to be a mul t i - contact co:::;;:ng gas dri ve

[ $

Reservoi r

oi l

woul d

enri ched

Wt;

i ntermedi ate-mol ecul ar- weightydrocarbonsf romthe

sol vent unti l the oi l woul d becomemsci bl ew th the

i nj ectedsol vent sl ug i n the swept zone. I n turn,

the l ean chase gas i nj ectedaft er the sol vent slug

woul d be condensed i nto the sol vent to form a

l i ghter reservoi r fl ui d whi ch woul d then become

msci bl ew th the l eanchasegas,

Tne S1i re- tubedi spl acement tests done i n 1969(17)

used

adaptedversi on of the method presentedby

Koch(f $) to determne msci bi l i ty condi ti ons,

oi l

recuvti ryat fl ood gas breakthrough was pl otted

agai nst di f f erent methane-ni tr ogencontents at a

constant

pressure greater than the sol vent

cri condenbarof 13, 100 kPag. Once a sharp decrease

i n oi l recoveryw th an i ncreasein methane- ni tr ogen

content was observed, the maxi mum content of

methane-ni trogenfor msci bi l i ty at that pressure

was

esti mated.

These experi mental

maxi mum

methane-ni trogencontents for msci bi l i ty,

y i f

h

correl ated cl osel y w th Benhams correl ati on

were then pl otted versu? the ethane-pl usmol ecul a;

wei ght of the gas (Fi gure7). Thi s f i gure showed

that msci bi l i tywas assuredi n the AA pool i f the

poi nt representi ngthe composi ti onof the i nj ected

sol vent was bel ow the l i nes representi ngthe two

experi mentalpressures,

The pseudoternarydi agramfor the AA pool msci bl e

fl ood was constructed fr omw ndow cel l PVT tests


4/16

RESERVOI RDESCRIPTI ONANDPERFORMANCEANALYSI SOF

4

A MATUREMSCI BLEFLOODI NRAI NBOWFI ELD, CANADA

SPE 196S6

(Fi gure8) (20).

Fromthi s d?agram two requi rements

Df the f l oodwere sti pul ated:

1.

Th~ ethane- pl us content of the sol vent

coul dnot b~ l ess than45 mol e percent.

2.

The mni mumdatumpressurer@st be 15 500

kPag, wh: ch woul d al so be consi deredthe

mni mummsci bi l i typressure.

Af ter the msci bl ef l oodconsnencedn 1972, the POC1

di d not per formas wel l as i ni t i al l y expectad

(Fi gure 2).

M sci bi l i ty was questi oned but the

cur rent rat ional e i s that msci bi l i t y has been

achi eved

and mai ntai ned.

Thi s r easoni ng i s

supported by the i ni ti al sl i m tube di spl acement

resul ts, actual f l ood performance and recent

di scover i es i n mul t i - cont act

di spl acement

mechani sms.

Recent l i terature has

star ted to explore the

l i mtati onsof usi ng one pseudoternarydi a~t; ;

descri be

mul t i - contact

i ~~~ ~~ yExperi mental

condensi ng- gasdri vemechani sm

Observati onshave i ndi catedthat the condensi nggas

dri ve

mechani sm i s

actual l y conbi ned

condensi ngi vapori zi ~g- gasdr ve mech~ni sm The

generati onof msci bi l i ty occurs by the extracti on

of reservoi r f l ui dcomponents i nto the sol vent ( i . e.

msci bi l i tydevel ops i n the forwardcontacts) rather

than by the condensati onof sol vent i nto the crude

Dil (i e. msci bi l i tydevel ops i n the swept zone).

Characteri sti csof the AA pool whi ch i mpl y that the

combi ned condensi ng/ vapori zi ngmec

) l \

sm i s i n

z; ;tct , based on thi s l i terature , are as

fol l ows:

1.

The cr i t i cal poi nt i s t o t he l ef t of t he

systemcri condenbarof 13100 kPag on the

pressure-composi t i onP- x) di a~ram

2.

The reservoi r temperature i s 84 degrees

Cel si us whi ch i s a

rel at i vel y hi gh

reservoi r temperature.

3.

The sol vent i s ethane- r i ch (15 mol e

percent ethane).

There i s di sagreement as to whether or not thi s

condensi ng/ vapori zi ngmechani sm actual l y devel ops

t rue msci bi l i t y,

even

though

the generated

di spl acementsare ef f ecti vel ymsci bl e and di spl ace

nearl

{

00 percent of the oi 1 i n 1aboratory

tests 21

The most recen+.work by Novosad and

Costai n(2~) provi des strori , ,evi dence that true

msci bi l i ty i s obtai ned through the mul ti - contact

process. Th~nwar~ concl udes that pseudoternary

di agrams, constr~cted

usi ng the

mul ti pl e- contactpath, cannot be used to accuratel y

predi ct the di spl acementof oi l by sol vent,

(a) Waterf l oodPerf ormancel , nalsi s

The AA pool was never tr ul ywaterf l ooded, Water was

i nj ectedfrom1971 to 1973 to i ncreasethe pressure

above the mni mummsci bi l i ty pressure of 15, 500

kPag pri or to the commencement of the rr i ici bl e

f1ood.

Water was agai n i nj ected i nto the aqui fer

f rom1975 unti l 1981 as an emergencymeasure when

the avai l abl egas quanti ti eswere not suf f i ci ent to

repl acevoi dage,

The pressure f l uctuati onsi n the

reservoi r refl ect these peri ods of water i nj ecti on

(Fi gure9).

Accurate defi ni ti on of the hypotheti cal waterfl ood

recoveryf actor i s an i mportant consi derati onas i t

di rectl y aff ects the i ncremental reserves over

waterfl oodatt ri butabl eto the msci hi ef l ood. Thi s

M l ul ti matel ydefi nethe successor fai l ureof the

enhancedrecoveryprocess.

I n 1970, the i ni ti al waterf l oodreco

the AA pool was esti matedto be 67%

~ ~~ a;~h~

recovery

factor was j ust i f i ed

by as~uming nil

resi dual oi l saturati oni n the caverns. I n 1972,

the msci bl e f l ood recovery factor was esti matedto

be 78. 3% by

the Al ber ta

Energy Resources

Conservati onBoard. The i ncrementalrecoveryf actor

attri butedto the enhancedoi l recovery processwas

therefore11. 3%

The newreservoi rdescri pti on,whi chdi d not i ncl ~ d

caverns and i ndi cated a si gni fi cant reducti on i n

OOI P, requi redthe re-def i ni ti onof th~ hypotheti cal

waterf l ood

recovery factor.

The theoreti cal

cal cul at i on of thi s f acto

[Y

as based upon the

Dykstr a- Parsons corr el at i on23 .

By varyi ng the

maximumand mnimumpermeabi l i tyvari ati onsexpected

i n the AA pool , a range f rom40% to 52% for the

expectedwaterf l ood recovery factor was cal cul ated

for a water - oi l r at i o 1i mt of _25 (Apendi x C) .

+

hi s range corresponds cl osel y 10--t e recorded

waterfl ood recovery factors i n other Rai nbowKeg

Ri ver pool s.

Si ncetheAA pool had been produci ngfor over twenty

years, i t was al so possi bl e to esti mate

hypotheti calwaterf l oodrecoveryfactorbasedon the

actual vol umetr i c sweep ef f i ci ency. The vol umetr i c

sweep eff i ci ency was opti mstic however, as i t

representedthe ef f i ci encyof the msci bl ef l oodand

not of a waterfl oodi n the AA pool . The cal cul ati on

shown i n Appendi x D provi ded a hypothet i cal

waterfl oodrecovery factor of 49% whi ch i s i n the

rangespeci f i edby the Dykstra-ParsonsLi near model .

(b) Current Hi sci bl eFl oodPerf ormanceAnal ysi s

The current recovery for the swept zone of the

msci bl e f l ood i n the AA pool can be determned

usi ngt he newgeol ogi cal sl i cedmodel shown i n Tabl e

2, I n 1987, the sol vent- oi l contact was esti matedto

be at 1285metr es subsea, Thi s was 18 metr es above

the ori gi nal oi l -water contact. From th~ sl i ced

model , the cumul ati ve

OOIPf romthe t op of t h r e f

5

to thi s sol vent - oi l contact was 8,755 x 10 m

U~i ng the cumul ati veoi l producti onof 6, 550 x 105

m, the recovery in the swept zone was 75% In

addi t i on, usi ng

the m croscopi c di splac t

ef f i ci encyof 95%determnedfromcore studi es

the vol umetr i c sweep ef f i ci encywas esti mated a;

79%

These parameters

i ndi cate a successful

msci bl edi spl acement process i n the AA pool . The

detai l edcal cul at i onsare shown i n Appendi xE.

(c) FutureHi sci bl eFl oodPerf ormanceAnal ysi s

Predi cti ngthe futureperf ormanceof the AA pool i s

compl i catedby two mai n factors:

1.

Water was i nj ected i nto the aqu fer and

di d sweep upr: ardsi nto the o ? zone to

some extent,

2, The remai ni ng oi l

bank cannot be

compl etel yproduceddue to sandw ch10SS,

292


5/16

.

SPE 19656 DI ANEE. BI LOZI R, PAULM FRYOL

5

I i aterI ndecti onin the AA pool was usedmai nl y as a

marginalrates because the product i onemphasi s has

pressure- regul ati ngmechani sm The net amount of

J

shi fted to recoveri ng the val uabl e natural gas

&;oOi n ected ;nto the pool was appruxi m?tel y

s l vent

3

bank

(current

whi ch correspondedto a maxi mumwater

l $~i l i ~pl ac;n= . ; 106m) .

l ev~l ri se above the ori gi nal oi l -water contact of

4. 7 metres.

However, the l ast f our wel l s dri l l edi n

Achi evementof the predi ctedperf ormancerequi resan

earl y 1987 showed an average oi l -water contact of

1302. 1metres subseawhi ch i s oi i l y0. 9 metres above

ef fecti ve producti on opti mzati on strategy whi ch

uses i nnovati ve producti on practi ses,

the new

the ori gi nal oi l - watercontact. Thi s i ndi catedthat reservoi r descri pti onand the unders: , andi ngf the

the de-wateri ngprocess whi ch commenced i n March,

msci bl e

di spl acement

1982 had been successful i n l oweri ngthe oi l -water

process,

The

current

producti on opti mzati on strategy i as I nvesti gated

contact to al most i ts or igi nal posi t i on at 1303

the fol l ow ngi tzms:

metres subsea.

In

addi ti on,

oi l should have

Rate- Test i ngprogram(xyl enetreatments) .

resaturatedt he waterf l oodedzone successful l yas

; :

Coni ng control (gas cycl i ng and reverse

~~r~~~~i t~[f$~es ~. c~~~r~&e~~~~c ~~eb~~

3 coni ng)

Hori zoi l talwel l technol ogy,

demonstratedi n o~ber reefs .

.

.

(b) Rate- Testi ngProgram

The second maj or i nfl uenci ngfactor on predi cti ng

futureperf ormancei s the magni tudeof the sandw ch

The prese~ce of asphal tenes i n oi l fromthe Keg

l oss.

Sandw ch l oss i s the amount of oi l whi ch

Ri ver zone i n the Rai nbow fi el d i s consnon.

The


6/16

.

A MATUREMSCI BLEFLOOD

.

.

RESERVOI RDESCRIPTI ONANDPERFORMANCEANALYSI SOF

I

RAI NBOWFI ELD, CANADA

SPE 19656

The l ongevi ty of the xyl u; ; etr eatment i s unknown.

I n . heKeg Ri ver B pool , xyl enewashes ar conducted

b. Gi venn some WO1l S as often as once a month )

the encou~agi ngresul tsof the rate- testi ngprogram

some of the poorer producers of the AA pool shoul d

benefi t f roma routi nexyl ene-washprogram

There are two drawbacksto doi ng xyl ene treatments.

Fi rst, al though i t i s a comparati vel yi nexpensi ve

procedure($15, 000Cdn, ) , the xyl ene treatment must

have a short payout peri odto be economcal because

the benef i tsmay be short term Secondl y, repe

xyl enewashesw l l di ssol vethe downhol epackers

:

resul t i ngi n expensi veworkovers.

(c) Coni ngControl Program

A coni ng

si mul ati on model

was devel oped to

qual i tati vel yeval uatet he ef f ect of maj or reservoi r

faci es on vari ous producti on strategi es.

The

bl ack-oi l program si mul ated

f i rst- contact

msci bi l i ty between an i nj ected sol vent and the

i n- pl aceoi l usi ngut. . ~mxi ng parameter approach.

The

si mul ator

one- equat~on

sequenti al

formul ati onto sol ve i mpl i ci tl y for pressure and

then expl i ci tl yfor gas and water saturati ons. The

sol uti on techni que was based on di rect Gaussi an

El i mnati on.

The bui l di ngof the coni ngmodel was simpl i f i edi n

two maj or ways because the qual i tati veef f ects of

reservoi r heterogeni ti es,and not the quanti tati ve

effects,

were the

mai n goal .

The first

simpl i f i cati onwas to accept the model s abi l i ty to

simul ate onl y fi rst-contact msci bi l i ty, al though

the AA pool i s a mul ti -contactmsci bl ~fl ood. The

secondmaj or si mpl i f i cat i onwas si mul at i ngonl y f rom

the current oi l

sandw ch

condi t i on,

whi ch

consi derabl yreducedthe si ze of the model .

The coni ng model was bui l t as a two- di mensional

radi al system(Fi gure12) , cnmposedof 9 l ayers and

7 concentr i c ri ngs (r=7; THETA=360degrees; z-9) .

Sol vent was l ocated i n the top layer , ot l was

l ocatedi n the next f i ve l ayers (15-metreoi 1 bank)

and water was l ocated i n the bottomthree l ayers.

One three- phase oi l producer was l ocated i n the

ceotre of the model .

Two pseudo-wel l s, a sol vent

i nj ector and a water i nj ector, were pl aced i n the

outsi de radi al r i ng and coul d i nj ect i nto the top

and bottom l ayers, respecti vel y,

The concentr i c

r i ngs were i ncreasedi n w dth i n a l i near tashl on

(mul ti pl i edby the factor of 2) to avoi d materi al

bal ance errors resul ti ng f rom l arge area changes,

The i nner radi us of two metres provi dedreasonabl e

f l ui d saturat i on prof i l es at the wel l bore whi l e

maintai ni ng numeri cal

stabi l i ty w th reaso~l abl e

t~me.stepsi zes.

The outer radi us of 239 mdres

refl ectedthe averages aci ngof the 16wel l s i n the

R

otal pool area of 291 ectares.

The constrai nts i ntr oducedi nto the model refl ected

typi cal f i el dl l mts,

Theseconstrai ntswere:

1.

The dat um pressur e at t he or i gi nal

oi l -water contact was mai ntai nedat 16, 100

kPa absol ute,

2, Al l vo{dage was repl aced by sol vent or

water i nj ecti on.

3.

Water i nj ecti onwas used onl y to mai ntai n

a l evel orf gi nal oi l -water contact.

4.

~~ ~& nufl , l l owabl e sol vent- oi l rati o

,

- , .

5.

The maxi mumal l owabl e

percent.

6.

The l owest al l owabl eoi

The si mul ati on programwa~h;~~

homogeneous

reservoi r.

heterogenei ti es, whi ch were ev

sandw ch f rom core and l og S1

i ndi vi dual l yi ntegratedi nto the

Theselmaj or f aci es:

? exposuresurf aces;

uater cut was 95

rate was 2n / d.

i ni t i al l yw th

a

maj or

reservoi r

dent i n the oi l

udi es,

were then

homogeneousmodel .

cl usteredvuggy porosi ty; and

: :

l ayers of al tered verti cal to hori zonta

permeabi l i tyrati os.

In order to understandthe ef fect of thesereservoi r

f aci es on coni ng, two types of produci ngstrategi ~

were i ntroduced i nto the f r~del :

gas cycl i ng and

reverse coni ng.

The gas cycl i ng strategy al l owed

oi l to be produced fromthe oi l bank and handl ed

i ncreasi ng amounts of gas,

The reverse coni ng

strategyal l owedoi l to be producedf rombel owthe

ori gi nal oi l -water contact and handl ed i ncreasi n

amounts of uat

i n the pas>~l $2 verse c0ni n9 has been studi ed

synopsi s

of cur rent

:: ~;: ; l $)y

ns of rev~rse coni ng I s provi ded by

and i ndi catesthat favorabl eresul ts are

achi evabl eusfngthi s producti onstr ategy.

Pri or to runni ng the si mul ator, the theoreti ca

maximumconi ng rates and perf orati onl ocati ons for

the oi l bank andwater zonewere cal cul ated

[m

the

: ; f l i j

i ons and f i gurespubl i shedby Cott i n

, respecti vel y.

For the producti onof ~~

str i ct l yfromthe oi l bank, the cri t i cal c i ngrate

for monophasi c oi l producti on was 16

3

/ d @ a

perforati on i nterval l ocated 7 metres bel ow the

sol vent- oi l contact.

For the producti onof oi l fr om

the water zone by reverse coni ng, the cr i t i ca

coni ng r te for bi phasi c oi l and water producti on

9

was 20 md of oi l w t h a WOR of 2. 4 ( tot al f l ui d

rate = 68 m3/ d) perf oratedat an i nterval 4 metres

bel ow

the or iginal

oi l -water

contact.

The

si mul at i onruns used these perf orati oni nterval sand

60%of themaximumconi ngr ates for the b, . : - . nnt, r

cases i n eachof the two produci ngstrategi e;

The resul ts of the si mul ati onruns were comparedi n

terms of predi cted sol vent- oi l rati o SOR), water

\

ut, recoveryof OOI P i n oi l bank and reakthroug

ti me.

A characteri sti cGOR curve for a typtcal AA

wel l was al so used as a reference to compare the

shape of the SOR curves generated f r om the

si mul at i onruns (Fi gure13) ,

The effect of oi l rate on coni ng i s shown for the

gas cycl i ng control case : hof i i ugeneouseservoi r) I n

Fi gure 14.

Bel owthe cri ti cal coni ng rate, the SOR

curvegradual l yi ncreasedw th no water cut, As the

oi l rate i ncreasedabove the cri ti cal rate, the SOR

and water

cut i ncreased not iceabl y and the

di f f erence i n ul ti mate? f~f~erybecame smal l er as

the SOR i ncreased.

as cycl i ng

s t i l l

recovered a notabl e porti on o

the oi l bank even

when si gni f i cant sol vent coni ng had occurred,

pr ovi ded t hat t he economc l i m t on SOR was

suf f i ci entl yhi gh enough,

The resul ts of i ntegrat i ng the three reservoi r

faci es i nto the homogeneous contng model are

sunnnari zedI n Tabl e 3.

The I ntroducton of

cl usteredvuggy porosi tyand vari ati onsi n vert i cal

294


7/16

.

.

CPF lQtVWi

DI ANEE. BI LOZI R. PAULM FRYDL

7

; Ohor zo, alpermeabi l i tyrat i os causedonl y mnor

l uctuat l ons I n 011 recovery.

However,

the

i ntroducti onof a _ exposuresurfacearoundthe

~el l borehad the greatest rel ati ve eff ect on oi l

. ecoverywhen comparedto the homogeneousc~se.

~or the gas cycl i ng strategy, the i ntroducti onof a

:urved l ens between the sol vent bank and the

woduci ng perf orati ons i ncreased the recovery uf

)(IIP

signi fi cantl y(Fi gure15). I n addi ti on, there

~as an asymptoti c i nc~easei n SOR whi ch i s typi cal

] f the GOR responsei nAA pool wel l s (Fi gures14 and

15).

A re - -se curved l ens was al so i mpl ementedto

epresent an exposure surf ace on the edge of the

eef and the resul ts sti l l i ndi cateda noti ceabl e

l mpro~~ementver the control case (Fi gure15) .

: or the reverseconi ngstr ategy, the curvedexposure

surfacewas very unfavorabl e f l ocated at the

ti l -watercontact.

The wel l producedonl y water &s

theoi l coul dnot cone i nto the perf orati or~socated

belOW the oi l -watercontact.

Usi ng the resul ts of the s:: em; i vi tystu. u; :; srom

the coni ng

si mul ati on

a

of

recommendati onsdel i neati ng the opti mumareas for

reverse coni ng and gas cycl i ng were devel oped

(Fi gure16).

(d) Hw zontal Mel 1 Technol ogy

Hori zontal wel 1 technol ogy i s a produci ngstrategy

uhi chcan provi detwo mai n advantages:

1.

reduce gas and/ or water coni ng through

reduceddrawdown; and

2.

i ncrease

contacted

pay,

i ncreasi ngwel l producti vi ty.

potenti al l y

The appl i cati onof hori zontal wel l technol ogy i nto

the maturemsci bl ef l oodoft heAA pool i s l ogi cal .

Theoreti cal l y,a wel l dri l l edhori zontal l yi nto the

remai ni ngoi l bank shoul dmni mzeconi ngand reduce

sandw chl oss. I n practi se, dri l l i ng a hori zontal

wel l for such a thi n target woul d be operati onal l y

di ff i cul t.

Wo mai n areas of tho AA pool were i denti f i edas

excel l entpotenti al l ocati onsfor a hori zontalwel l .

Ver ti cal i nfi l 1 dr i11i ng i s not economcall Y

feasi bl e i n these areas because of the thtn pay.

The areas i denti f i edwere the northeast corner and

westernedge of the pool (Fi gure16) .

a)

ReserveEsti mates

1, The new~eservoi rdescri pti oni ndi catd a

%m

ori gi nal oi l - i n-pl aceof

11.0

x

10

vol umeti tcal l yt

Thi s was a si gni f i cant

de re se fromthe 1972estimateof 15. 9 x

1O$m~. The decreasewas supportedby the

i ncreasedwel l database and 3-D sei smc

data.

2,

The vol umetr i cOOI P of 11. 0 x 106 m3 was

conf i rmed by a

materi al

balante

cal cul ati on

after re-eval uati ng

the

i ni ti al esti mateof the aqui f er si ze.

b) Perf ormanceAnalysl s

10

The AA pool achi evedmsclbi1i ty througha

296

mul ti - contacti ngmechani sm The i nabi l i ty

of the pseudoternarydi agranrw represent

thi s mul ti - contact

/

ath expl a;ned the

previ ousconcepti ono i rm i sci bi l i ty.

2. The hypothet i cal

waterf l ood

recovery

factor was cal cul atedto be 49% whi ch i s

si gni f i cantl yl ower than the 1972esti mate

of 67%

The decrease was j ust i f i ed

theoreti cal l y and through actual fl ood

pc: f ormance.

3. The current recovery factor of the

msci bl ef l ood i s 75% whi ch i s l ower than

the 1972 esti mate of 78. 3% Nowever, due

to a four- metresandw chl oss, the overal l

recovery factor w l l be 70%

Remai ni ng

3

recoverabl e oi l i n t e oi l bank i s

approximatel y1, 105x 10 m3.

4.

Furt her refi nement

of the depl et i on

strategyi s requi redto ensuremaximumoi l

recovery.

c) ththodol ogyfor ReservotrHanagemwt

Thi s study demonstratedthe nevrengi neeri npparadi gm

and the appl i cati onof i

engi neeri ng

technl quest~~~i gat?e eo~i z~~~

i ncorf matedthe i ntegrat~onof geol ogi cal data w th

engi neer i ng data to re-devel op the raservoi r

descri pti on upon

whi ch t he AA pool vert i cal

hydrocarbonm{sci bl e f l ood had been desi gned. The

f ramework for arana~i ng maturs msci bl ~f f l oodwas

establ i shed.

i mpl ementati on

recent

technol ogi cal advances were di scussed as i ntegral

co, , ~onents i n the on-goi ng devel opment of an

opti w zedproducti onstrategy.

f ormati onvol ume factor

compressi bi l i ty

mcroscopi cdi spl acementeff i ci ency

vol ume factor for expansi or:of f l ui dand

rock abovePb

recoveryfactor

vol umetri cdi spl acementeff i ci ency

cumul ati ongas producti on

gas-oi l rati o

i ni t i al gas cap to oi l zone rati o

cumul ati veoi l producti on

md-poi nt perf orati ons

ori gi nal oi l - i n- pl ace

pressure

oi l r at e

recoveryf actor

producedgas-oi l rati o

sol uti ongas-oi l rati o

saturati on

sol vent- oi l rati o

vari ati onof permeabi l i ty

cumul ati vewater i nf l ux

water- oi l rati o

cumul ati vewater producti on

SUBSCRIPTS

b

= bubbl epoi nt

f

= gas

= i ni t ial

o = oi l

t = total

w

=water


8/16

1.

2.

3.

4.

5.

6.

7,

8,

9.

Ml l hei m K. K. :

TheNewE i neeri ng Paradi gm

and the

Emergence I nvest i gati ve

Engi neeri ng,paper SPE 18103presentedat 63rd

Annual Techni cal Conferenceand Exh bi t i cnof

t$e Soci ety of Petr ol eumEngi neers, Houston,

Texas, October 2- 5 {1988) .

Wl l mon, G. J . :

Verti cal M sci bl e Fl ood to

Hi ke Recover; By 70 M l l i onBarrel s,w d Oi l

( J anuary, 1966) 75- 78.

Omoregi e, 2.S. and Jackson, G.R. : Ear ly

Perf ormance of a Large HydrocarbonM sci bl e

Fl ood at the M tsue Fi el d, Al berta, paper SPE

16718 presented at the 62nd Annual Techni cal

Conference and Exhi bi ti on of the Soci ety of

Petrol eumEngi neers, Dal l as, Texas, September

27- 30 (1987).

J onasson,

.

Reservoi r

Survei l l ance

Program J u~yp&eek Beaverhi l l Lake A Pool

Hydrocarbon$i i sci bl eFl ood, aper prepri ntNo.

6-37- 34presentedat the 37t Annual Techni cal

Meeti ng of the Pet rol eum Soci ety of the

Canadi an I nsti tute of M ni ng and Metal l urgy,

Cal gary, Al bert a, J une 8- 11 (1986) .

f l cI ntyre,F. J . and Pol kowski ,G. : Radi oacti ve

Tracer Appl i cati on to Moni tori ng Sol vent

Spreadi ng i n the Rai nbow Keg Ri ver 8 Pool

Verti cal HydrocarbonMsci bl eFl ood, paper SPE

14440 presentedat the 60th Annual Techni cal

Conference and Exhi bi ti on of the Soci fJ ~ad; f

Petrol eum Engi neers, Las Vegas,

t

September22- 25 (1985) ,

Da Si c, W et al : Assessmentof a Vert i cal

HydrocarbonMsci bl eFl ood i n theWesternNi sku

D Reef, paper SPE/ DOE 17354 presentedat the

SPE/DOEEnhancedOi l RecoverySymposi umTul sa,

Okl ahoma, Apri l 17- 20 (1988) .

Mazzocchi , E. et al :

Tert i aryAppl i cati onof

a HydrocarbonMsci bl eFl ood, Rai nbowKeg Ri ver

8 pool , paper SPE 17355 presented at the

SPE/ DOE Symposi umon Erl hancedOi l Recovery,

Tul sa, Okl ahoma, Apri l 17- 20 (1988) .

Backmeyer, L,A, , Gui se, D,R. , KacDonel l , P.E, :

TheTert i ary Extensi onof the WzardLakeD- 3A

Pool M sci bl eFl ood, paper SPE ?3271presented

at the 59th Annual Techni cal Conference and

Exhi bi t i on of t he Soci ety of Pet rol eum

Engi neers, Houston, Texas, September 16- 19

(1984) ,

Benni on. D. W and Stewart . B. : Si mul ati onof

a Di rect l y Msci bl e Vert ical Di spl acement

Hydrocarbon Solvent

Fl ood ~

( J anuary-February,1987) 97- 103,

In.

11.

12.

13.

14.

15.

16.

17,

18,

19*

20,

21,

Rei 4zel , G. A. arsd Cal l ow G.O. :

Pool

t

Descri pti onand P formanceAnal ysi s Leads to

Understandi ngGol d

Spi k~ s M sci bl e Fl ood,

M sci bl eS~~f~w ~ses (SPERepri nt Seri al No. -

M

Petrol eum Engi neers

Ri chardson, Texas (1985) 580- 589.

Sl otboom R. A. and Ambl er, J , S. : Reservoi

Depl eti on Study -

Rai nbowKeg Ri ver AA Pool ,

Rai nbowFiel d, Al bert&aeNOCAN R69-47PEE- C)

appl i cati on Resources

Conservati onBo~~d, J une 9 (; =~~~

Sl otboom R. A. et al :

M sci bl eFl ood Study -

Rai nbow Keg Ri ver AA Pool , Al berta (NOCAN

R71-53PEE-C), appl i cat ion to the Ene y

7

esourcesConservati onBoard, October 1 (1971 .

Trach, MR.

and Matthews, MW: Econ6m

Eval uati on of Sol vent Fl oodi ng, Rai nbow Keg

Ri ver AA Pool , Al berta {MCCAN R?3-22PEE)

appl i cati onto the Government of the Provi nc

of Al berta -

Department of Energy and Natural

Resources,October 16 (1978).

Schmdt, V. et

al:

t4i ddl e Devoni an

Cementati on Peefs Encased i n Evaporates

Rai nbow Fi el d, Albwta, Roehl , P.O. and

Choquette, P. U. , eds. ,

m

Spri nger- Verl ag, Berl i n (1888

- ,

Qing, H. and Mount j oy, E.W:

y$~ti sta*

?

ol omti zati on i n Rai nbow Bui l dups, Hi dde

De\ oni anKeg Ri ver Formati on,Al berta, Canadam

~ (1989) 3 4, 114-126.

Craf t, B. C. and Hawki ns, M F. ,

v

t prenti ce-Hal

I nc. , Engl ewoodCl i f f s, NewJersey (1959) 218.

Humphri es, C. L. andMcCarrol l , J . : Rai nbowM

Msci bl e Fl ui ds Study (RR691230- l FR),Nobi l

Research and Devel opment Corporati onResearch

Department, Fi el d ResearchLaboratory, Dal l as

Texas, December 30 (1969) .

Koch, H. A.

and Hutchi nsorr,C. A. : M scibl

Di spl acementsof Reservoi rOi l Usi ng Fl ueGas,

~, AIM (1958) u, 7.

Benham A, L, , Dowden, WE, , and Kunzn an,WJ . :

M sci bl e Fl ui d Di spl acement - Predi cti onof

~~~ci btli ty, ~ (October,

1960

*

George, R. A. and Hol l abaugh, G.R. : Hi scl bl

Fl ui d Di spersi on, Rai nbowAA Reservoi r, Canada

(RR700505-1FR),Mobi l ResearchandDevel opmen

Corporati onResearchDepartment, Fi el dResearc

Laboratory,Dal l as, Texas, May 5 (1970) .

Z ck, A,A, :

A CombinedCondenslri g/ Vapori zi

Mechani sm i n the Di spl acement of 011 by

Enri chedGases, paper SPE 15493 presentedat

the 61st Annual Techni cal Conference and

Exhi bi ti on of t he Soci et y of Pet rol@u

Engi neers, NewOrl eans, Loui . :anna, October 5- 8

I 22,

(1986)0

Novosad, Z.

and Costai n, T. :

New

I nterpretati on

of Recovery Mechani sms i n

t?

A MATUREMSCI BLEFLOOD

~

The authorswoul d l i ke to thankMobi l Oi l Canadafor

perm ssi onto wri te, present and publ i shthi s paper.

The authors woul d al so 1ike to thank Ri chard C.

Sydor who greatl y assi sted ; n runni ng the coni ng

si nvl ati onmodel .


9/16

.

., ,

SPE 19656

ti I ANEE. BI LOZI R. PAUL M FRYDL

a

Enr i ched Gas Dr i ves, J , Cdn, Pet . Tec~

(March-Apri l ,1988) 54- 60.

23. Crai g, F. F, :

The Reservoi r Engi neeri ng

Aspects of Waterf l oodi ng, Monograph Seri es,

Vol ume 3, Soci ety of Petr ol eumErgi neers, New

York (197ij 79-80,

24. McNi el , J . St : Bot tom Water i nj ect i on -

Rai nbow AA Puol - Fl ow Cel l Studi es ,

correspondence to I t, J .

Cl auser from ?i obi l

Rssearch and Development Corporati onResearch

Department, Fi el d ResearchLaboratory, Dzl l as, ,

Texas, August 15, (1972) .

J

25. Van Lookeren, J . : 0 1 Product i on f rom

Reservoi rsw th an Oi l Layer Between Gas and

BottomWater i n the Same Sand, J , Pet. l ech. .

(March, 1965) 37.

26. Si nnokrot, A.A. ,

Mobi1

Expl orati on and

Produci ng ~ervi ces, Dal l as, Texas, personal

communi ca, tl on,March (1989) .

27. Cott i n, R. H, andDmbret, R. L. : Appl i cati onof

a Mul ti - phase Coni ng model t o Opt im ze

Compl eti onand Producti onof Thi n Oi l Col umes

Lyi ng Betwen Gas Cap and Wate~aZone, paper

SPE 4632 presented at the 48th Annual Fal1

14eeti n of the Soci ety of Petrol eumEngi neers

if AI E, Las Vegas, Nevada, September 30 -

October 3 (1973) .

28. Odeh, A. S. : Fl ow Capaci t y of Wel l s w th

Li mted Entry to Fl ow, YEJ ~ (March, 1968)

43- 51.

APPENDIX. material Balance Wsulatfm

Cf= 4. 06x 10-7; Cw= 4. 35 x 10-7vol / vol / kPa;

Sw= 0. 082 (f r.); m = O; Pi = 16,090 kPag;

b -15$159 kpa; p -14 933 Pag

Boi = 1. 3046; B = 1. 3040rmm ;

Np = 126, 600m ; Gp = 13, 216x 103m3;

Rsi = 92, 73; h = 91.30; Rp

10 ,39 m3/ m3;

; : ; : ; :~: ;; ; : : &70 m3&

~ ~f . O rm3/ m3;

p=81m We=6~, 000m

N

Bt + I RDRsi l Bol We+~

= 11 x 106m3.

- Bti + i f + mBti ~Bg/ Bgi- 1]

1X B. l l gyi ferS~

~ = Ct*Del taP (Ref . 17)

Potenti al Aqui fer Si ze

Stabi l i zedI kte rI nfl ux= 63 x 103m3 (Fi g, S)

Ct = Cf + Cw= 8. 41 x 10-7 vol / vol / kPa

Del ta P - total pressuredropUnti l

stabi l i zati onof water i nfl ux

- 14, 834= 1, 256kPa

Thus, po~e~f{~faqui fersi ze = 60 x 106m3,

WOR-25; Mobi l i tyRati om 1; SW O. 082 (fr. );

V = 0. 48 (Lower Li mt) ; V -0. 1 (

yY l

r Li mt)

FromDykstra-ParsonsLi nearModei

LOWERLI MT: ,

EF(l - O. 52*SW= 9. 379; Er = , 40

UPPERLI MT:

1

r( l -O. 52*Sw=0, 50; Er = , 52

D. ~f l ood ~vorw =

Sw = 0. 082; Sor(WF)=0. 35;

Ev-

0, 79 (App, E)

Di spl a~~nt Ef f i ci ency=~yi - Sorl WF~= 0, 62

~)

1 - Sw

Water l oodRecovery= (Ed)(Ev) = 0. 49

~mw

OOI P=

l1,000x 103m3

Sol vent-Oi l Contact (1987) = 1, 285msubsea

Depth at Top ofRe, \ f = l , i 42, 9msubses

hLiCal

klOUllt sWC@ - -1,142,9+1,285142,1 M

Swept OOI P (usi ngTabl e 2)

=8,727+[(142.1-141.8)/ S. 1]*571=8,755103m3

Ed = (Soi - Sor) So = (0. 92- 0, 05)/ 0. 92s0. 95

$4

Np =6, 55OX1O m

Recover?of Swept Zone = (6, 550/ 8, 755)= 75%

Ev. (Rf / kd)m(0, 75/ 0, 95). 0, 79

Oi l 8ank Thi ckness (1987) 181s

Amount of Uater- Fl ushedOi l Bank =4, 7m

Sandw chLv:s = 41S

OOI P BelowS\ ~l vent-Oi lContact (Tabl e2)

= 571(5. 8/ 6. 1)+776(6. 1/ 6. 1)

+ 926[{(6. 1- 4. 7)+4. 7*0 51)~/ 611

= 543 + 776 + 576 = 1, 895X 10 n+

ExpectedRecoveryof Unswept Zone = 75%

Remai ni ngRecoverabl eOi l

= [((18- 4) / 18*1,895*0.75]= 1, 105x 103m3

i

otal Recovers l e Oi l =6550+1105=7655x 103m3

Ul ti mateRecovery= (7, 655/ 11, 000)= 70%


10/16

----- .- . -.

1. AverageRock

Porosi ty,

AverageTh

AverageOl

Average01

ROCKCompr

~, Fl ui dOl strl b

ConnateWa

Orl gi n41O

Current 01

3. Reservoi r Pre

Datum mei

Ori gi nal P

Current (1

4. Fl ui dPropert

Saturatl oc

Fl ash011

at I n

at Sa

Fl ashSol u

Otl Oensl t

oi l Vi scos

Reservoi r

Oi l Compre

Mater C

Y

, Reservoi r o

Area, m

Otl Zone R

Ori gi nal a

Ori gi nal O

6. Aqui fer Data

RockVolum

AveragePa

Vol ume, 10

kopert l es

i ercent

I ckness,metres

Zone Hori zontal ?ermeabl l i ty,md

I

Zone Vert i cal Permeabi l i ty,md

msi bi l i ty, vol / vol / kPa(g)x 10-6

hi on

; erSaturati on,percent

11- l i aterontact?metres subsea

- datarContact (1987) , metres subsea

; sure

essubsea

essure,kPa(g) at datum

189)Pressure, kPa(g) at datum

1es

Pressure, kPa(g)

oluma Factc*, res m3/ st m3

ti al Pressure

; urati onPressure

; i onGa~-Oi l Rati o, m3/m3

t, g/ cm

l tyat I ni ti al Condi ti ons,mPa, s

e eratureC

Tsi i l i ty, vol / vol / kPa(g)x 10- 6

essi bi l i ty,vol / vol / kPa(g)x 10-6

IIMS

(1989)

tckVol ume, 1 3m3

l - i n- Pl ace, ?;~m~~l f i 3

i l Content,

;1989

i

) , 10m3

;0 i ty, percent

tm

8*6O

63. 11

4500

875

0,4S6

8, 20

- 1303, 0

- 1 302, 1

- 1~: 4: i :

16150

15 160

1,3046

1,3070

0. 8 ;

0.472

84. 4

1. 84

0.435

2910000

183687

0.060

11000

1 763

5;

Jablez. WmwuUIM f ort he~

234

112

453

750

908

:

; ; : : 4

6

1221

1201 :

571

776 1

926

11

\ TI VE

: P

J &

34

146

fgg

i 49

157

i 23

105

i 26

127

98

174

)00

THI CKNESS

CUMULAT VE

OF SLICE

DEPTHFROMTOP

- a ~

;;.;

12: 2

12*2

1202

24, 4

18, 3

12, 2

1:,;

6:1

6.1

25,9

38, 1

50. 3

; : , ;

99: 1

117, 4

129, 6

141, 8

147. 9

154*, O

160. 1

294


11/16

Tabl e 3. Rel ati veEf f ectsof Reservoi r Faci es on Produc

i ne $tr ateai es

RELATIVEEF)_ECT

RELATIVEEFFECT

RESERVOI RFACIES

EVERSEC

ONl &

Exposure Surface

Favorabl e i f above

Unfavorabl e i f

perf orati ons.

l ocatedat oi l -

Curvatl l m s i mmant .

water contact.

Reversecurvaturei s

not s f avearabl eas

noraal curvature.

ClusteredVuggy

Margi nal l y

Marginal l y

Porosi ty

unfavorabl e.

f avorabl e.

Anisotr opyFactor

Marginal l y

margi nal l y

Vari ati on

unfavorabl e.

favorabl e.

MOTE: Eff ects are relati veto homoge,wus reservoi r.

Fkl nBcuo Flood PmdMcum

1971

188: -

lsisl 2 1


12/16

I

*

t

I

H-t--i

I

I

IL


13/16

II*

SPE 96 6

I

t-

sol


14/16

SW 96 6

4\-=-\

0.,

I I

T

I

I

o

I 1 1

400

800

1200

1600

OI L RATE (mS/ day)

F19. 11- J un.

1988 and Oetobor 1988

IPR Curves for 12-13-11O-6W6M

0,093

0,025

0.0

0,018

0,0 0.0

Fig. 12-

~~-~1~. nsl onal

Radial Coning

Modol &ld System


15/16

~

,, ta

sPE 96 6

2,0

3

0.6

0

1

8MDCYIWED

3

,..=2

@

AOTUAL -

1

t

[RA

~)

1.2

1.4

1.6

1.8

2:0

CIMJLA TIVE &% %GTlON

(ma )

Fig. 13- QOR vs. Cumulatlvo 011ProductIon for

Typical AA WON(10-14-11O-6W6M)

e

0

0 10

20

60

40 60

60

70

PEROENT RsOovmv OF w ~

m

Fig. 14- SOR and Water Cut vs. Porcont

Rocowry of OOIP for Throo Rates

In Homogonoous Ro orvolr


16/16

WE

96 6

6-

~Lms

e;

I

2

i

~

CIJnvEDlsm

0 ~

1

-~

o

10

20 so

40 so

60

70

ao

Pmm47nEcOveRY oFOow l

Fig. 15- SOR vs. Percent Rocovory of OOIP

for Curved Lens -

s

Cycllng Strategy

1

1

n

...,.,,

.:;.:

,,,.

KILOMETRE

1

GAS CYCLING

REVERSE CONINQ

HORIZONTAL W

Fig. 16- Rocommondod Aroau for lmplomontatlon

of Optimum Producing Stratoglos

S t

Documents

19656-Reservoir Description and Performance Analysis of a Ma