GENERALIZED ANALYSIS OF THE MULTI-WELL INTERFERENCE TEST IN HYDROCARBON RESERVOIRS

l t t l l . ( l l . l ( ) l i l \ l / ( / / l : \ G l \ l ' . l i R l , \ G l \ , 1 ) t l : ( 1 1 . \ o l . o ( ; ' l l( l ) 2 0 i l . 1 : l - 5

(, I - \ I.-

IT \ I.I7.I.I) .\NA t.\'S I S O F' TH E N{

U I,TI-WELI, I NTE RFE RENCE

. I E S ' T

I \ I I Y I ) I T O ( ] A R B O N

R E S E R V O I

R S

l ; l l a d c . ( i . K . a n d l s c h u r t u a . S . ( ) . l ) t ' g r l r l r n e n t o l ' l ) e l ro l e u n r l i n g i n c c r i r r g .

I r r i r e r r i l r o l l b a t l l r r . \ i g e r i a . I R . S ' l ' R . t ( ' , ' l '

I'ltis stttd.t'prtsa,tts u sanerulizttl uttull'tit'ttl .fonnulotion of th( LIulti-ll'ell Intarlercucc lt'st problam usitr14 tltt co,,tqrt of' the sour(e unil sirtk ./irrtt'tiotts us a tool Jitr soh'iug the basic irtltttcrencc equuliotts. 7-ha muc'h brouder (ilse, .la(trtrittg inner rrell houndary conditittus tt'itlt ,tkirt und storug(.frrclttrs ut hotlr tlte uctiva unil tha \tJvarol obscrvuliort x,ells, is cottsiilered. T'he garrcrul ttolura o.l' tltc .fbutrrtlutiort ullox's .for the o,tull'sc:; oJ' tron-hotrrogettcous reservoirs ond ltettct,Iltct'ttttt,ep|'soJ'rL'serltliriircctittttuIpaunauhiIit,|,andthtreIutctIi.r.rlrt,.roJ.re'strwlir

u.rc.s rtl ltcutrrubilit.t' w(r.! uililrasst'il. :llost o.l' tltc prtblislt(il tuscs oJ intelercnc( tesl.\ wcre iilentiliad us litrtitirtg t'ust,s o.f tltt, uL't,(ruli:.ed Jbunulutiutt.

| \ t ' t { o l ) t ' ( " 1 ' t o N

I ) r e s s u l c I ' r a u s r c n t A n a l y ' s i s h a s b e c t r r l e a \ c r \ ' n l l p o l t i l n t t o o l f b r r e s e r v o l l c l t l l a c t c l r z u t r o n . ' l l t c n r o s t e o r r r n . r o n l v u s e d p r c s s r n c t l u n s i c n t ln a l y s r s t c c l u r r q u e i s t h c s i n g l e r v e l l t c ' s t , c i ( h c r r n l i r r r n o f ' p r c s s u r e d l a u ' d o * n o r p r c s s u r e b u r k l - u p l c s t s ' l ' h c s e t c s t s u r c b a s e d o n t h e c a s ) ' a s s u n r p t l ( ) n o l ' h o r r r o g c r t t o t . r s r c s c r v o i r s . a r t d a r c t h e r c l i r l c lr n r r t e d l o t l r c c r a l r r a t r o r r o l ' r ' o l u m e - a r c l a r e t l l r t r r i z o n t a l p c r r r r c a h i l r t r ' o l l h c l c s e r v o i r z o r r c c o n l 0 c t c ( l r l u f n r g t h c t c s t . I n v r e r r o l t h e a v e r a - s i n g p r o c e s s o t ' t h c s c t r \ t s t h e \ u r c n ( ) t o n o u s l v i n c a p a b l e o l ' c l u a u t r l ' r , i r t u l a t c l a l r a n a t r o n s r n r c s c r r o i r p r ' o p c r t i e s n o n r a t t e r n o \ \ 5 e \ e l c .

! l u l t i - $ e ll i n t e r f - e r c n c e t e s t s . f e a l u n n g a n a c t i r e s c l l a n d o n e o r n r o l e o b s e r v a t i o n r v e l l s d o . u n l i k c t h c s r n g l e - u c l l t c s t s . p r e s e n t p o r v e r l i r l u l t c n r a t i r c n r c a n s o l ' t r s i n g u e ll t e s t a s a l e s c r l o i r c h a r a c t c l r . / u t l o u l o o l . I n t h i s k i n d o f i n t e r l L ' r ' e n c c ' tcsls. re scr\'()lr paral-lle ter s that rclale to rnter-$ c'll p r ( ) p c l t l c s , s u c l r a s t h e p r o b l e n r s o f d i r c c t i o n a l p c r r u e a b i l r t v ln h c t c r o s e r r c o u s r r - s e r \ o i r s . a r e l d d r c s s r ' t l . I ) i l c c t r o n a l p e r n r c a b i l i t v h a s v e r y s t r o n g t n r p l r c a t r o r t s r t t r t o n - l r o r t r t ) ! l c n c o u s r c s c ' r ' r ' o r r s w h e r r L ' r l e n r a l e n c r l l v in p u t i n f o t - n t o { ' l ) u r c l rn ; c c t r r r n r s r c r l u r f c d t o J r . l q l l r e r l t r , i t t t r r a l r e s c l v o t r c t ) e l g \ ' . l r r tl t e s C r ' J s c s . g ( ) o ( l r r n d c r s t a , t d i n u o l ' t l t c n a t u r c o l ' r e s e r v o t r l l c t e r o u c n c l l ) ' , a r r d t l r e d i r e c t i o n a l p e r r r r c a b r l i t l a r c v e r v u n p o r t a n t r n o r l c r t o c h o o s e t l t e o p t r r n t r n t l l r u t l

lloocl pattern orientrtion that u oultl reduce the aclvcrse e l'l'ects ol- llurtl clrauuclrnq on arca s\\ L'ep c l ' l i c r e n c y . S r n r i l a r l l ' . i r r t l l r l e r t o o p t r n r i z e l l r o d u c t l ( ) n f l ' o r r t l t o l i z o n t a l u e l l s , k r t o r r l c d g e o l ' c l r l c c t r o n a l p e r n r c a b i l i t y a n t l o r t h e p r i n c r p a l a x e s o l -r c s c n o i -r p c -r -r n e a b i l i t y ' a -r c c s s e n t r a l s o t h a t u c l l s a r e p r e t i ' r a b l 1 ' d l r l l e d o r t h o g o n a l t o t h c t l r r c c t r o r t o l ' lllax l nlLl r-n pcrnreab _{rl it 1'.}

A f e u p a p e r s h a v e r c c c u t l v b e e n p u b l r s h e d o n t h e e v a l u a t i o n o l ' c l r r e c l i o n a l p e r n r e a b i l r t y u s i n q n r u l t i - u c l l r n r e r l ' e r c r . r c c t c s t s ' r I ' n o n e o f t h e s e l r a s a t t e n r p t c d a u n i f i e d lr c a t r n c n t o l ' tlre problenrs ol- hetcroscneilv anrl possrble clirectional pcrnre ability rn interl-e rcnce rr cll tcsl In this paper \\'e s rll attenrpt to lorr.nulate the interl'erence rr'ell test equatious rn a reneralized fbrm using the concept of srlurqe funclions. This tbnnulatiou would bc sufliciently gencriil such that

cases involvlng honrogeneous reservorls can be

considered as special cases, anri therefore nrost <;f' t h c p u b l i s h e d i n t e r l ' e r c n c e c q u a t i o n s c a n b e s e e n a s I i m i t i n g c a s e s o l - t h e s c n c r a l i z e d e q u a l i o n .

P I T O B L E \ t F - 0 t { u t ' t - A l ' t o N

\ \ f e c t r t r s i i l e l t h e c a s e o l - le s t \ r v r t h a s i n - q l c a c t t v e u c l l a r r d s e l c r u l o h s e ' r v a l r o r l u e ' l l s a s s h o r v n i n t h c s c l r c n r a t i c b c l o r i .

I'iilalc, (i.li. unl Isth unnu, S.O .' L..l I iTI:('l I Journul ol' I')ngiuctriug atil 'l'tch nologl' I ( I ) 200.1: I - 5

l l r t ' r c l c v l n t d r s t a n c c s l ' r c l r r ' c r ' n a n y o h s c r \ ' . r t i o n s c l l ' l l ' a n d a c t r v c r v c l l 'l ) ' a r c a s i n d i c a t e d i n l h c s c h c r u a t r c . l'ltc prr'ssurc rcsp()nsc lt lhc tlbsclvatiou ncll 'R'duc to a protlucliort pulsc at lhc aclive wcll '1". is atll'ctetl bv prcssurc intcrll'rcncc liorrr all thc othcl rrclls sithin its ur'ightrorhood. 'l'hc lcvcl ol'intcrll'rence duc to cach ol' lhcsr'surrounding s'clls is nornrally ir tirnction ol'thc ratc at *hich thc rrcll is prtlducctl as rvcll as its distancc l}ont lltc obscrvalitrrt scll. 'l'ltc prcssurc rcsponsc lirnctiou at thc scllborc ol'tlrc ohscrvutiorr rrcll can bc ('\prcsscd. rrt l-aphcc spucc. using thc principlc of supcrposition rn spucc iu a gcncrrlrzctl intcrll'rcncc cquatlon git'crt rtstt):

P ; 1 r s 1 p p , l . ) 1 ' r 1 , ( i ( r s y 1 , n . ) , ) t , r s p ( i ( 1 1 ; n r r . t r ) . _I r o x , ( i 1 r ' 1 , p , . ) . )

t l 1,tt

In thts cqualion. it rs pcrtur('nl t(r n()lc thlt lltc distartcc tlcsrgruttiort. r1;1,p antl r1;ss nlr,lst c:rch hc unlll slndc lhc) dcscrihc tlrc tlistrncc rll'thc activc scll lnrrrr llrc lclivc scllborc location and lhc obscrvalurrr ucll lirrnr thc obst'rvllion scllhorc location rcspcclllcl\'. I'lrr'lirctor (rlt rcl'rrr'scnls lhe scightrng tirnctiorr that rcllccts tlrc lctcl oIptessurc tlonrirtrtrtcc' of ln1' plrtrcrrl;.rr adioining s'cll at thc obscrva(rort scllbtxc.

Prcssurc Profilcs rt 'l'he Obscrvation \\'tll

['sing lhr'ahove solution sclrr'nrc. lhc prcssurc !'qualions at all thc 'N'observatirtn sclls. tlkrrrs account of thcir r('spectivr' $ellborc Skirt l'nctor (Snn). r:ln trc crprcsscrl as:

P111161ri;sp.l)

\

t o p ( i ( r ' 1 y p p . ) . )

, ursslSsp.

( i ( r 1 . , p 6 . t r )

_I

,

l < o * , G ( \ , * , , 1 )

.

l ' R

ol' scllborc- Storage constanl liqurtion I. conturns

(Cr,nri) lntl thc othcr

tupICp6ptrti1 r''u'*. _{l) |}

parJtu('lcrs trr1, rrld rrrp, \'lticlt can br' rchtr'tl tltrough the usc sr'Ilborr' bountl:lrv contlilions lo obtain:

(-1111p ).

T

. ( t u t ' t p , ( r ( t ' 1 r p , . / , l - .

t-( J..R ) to thr' producrit-(rn ralc attlre actrlc irp is thc rrlrr) ol'thc llurtl protluctron rltc'irt thc'()bscrv:tlion rrt'llbtrrr'

sr'llhtrrc (P).

Equatiorr 3 is a st't of N indrcirl r'qurlions. one equation tirr each trl' ncll test.

Pressure Proliles at The .{ctive \\'cll

Prtrceeding as in the obsen'ation well casc. the pressure response cognizance of the pressure interference frorrr all the obsen'ation s'ells,

Ppp( r1;pp. ), )

\

t o p [ G 1 r 1 . y p p . t r )

r Sn J*

_f

t o p , G 1 r p p , . ] . )

. . . .

t = l

the obsc'rvation s nl the multi-observation

equatron at the only activc s'ell, taking can be expressed in Laplace space as:

And tht' srngle indrciirl equJtion thilt rr'htes (0Rrs and tup is gir r'n ls \

s l t u p i l * C n r ) * [ S p = Glrppp.).)]l - ('','i.

] t : r p , ( i t r ' p , . i ) ' - : - . .

r j r l '

t

I

f'ulule, G.K. unl Irthunn'u, S.o 1,.41 f ECII Journu! ol'Lntitrttrittg ttni Trchnolo1y 1t Il 2003: l-5

l : q r r a l r o n s I a r r d 5 c o n s t i t u t e c s c t o l ' ( \ . I ) s i n r u l t a n c ( i r . r s c q u a t r o r ) s 1 i o n 1 u l t c r e a l l t h e t i n c t t o n s , | . ( r ' r 1 1 , , _i 1 . 1 . 1 . . . \ ) c a n b c c r a l r r a t c c l . ' l ' h e s e e q u a t l o r l s c a n b r L ' \ p r c s s e d n r t e r m s tl f V c c t o r - \ l a t r r r

r l r ) l i . l l l ( ) n J S :

, l

r t .

, I

- l

/ . 1

" i _ / _ l

i i . l I I

. I

, . I

r / / ' l

I

, 1 |

, t" I

I

l"

! t

I

l =

I

I

' ' I

I i

I

, (.1. U.

l

iU-i l . , ' i t . . : i I . . ,

i l r . , r t 1 1 . . . 1 _r

I t ( , ) , , .

: r ,

i

| / ' \

t " r ,

1,.,.,,

l h r . ' la r g e r tl r e n u r l b e r o l ' t h e o b s e r r ' 0 t l o n \ \ c l l s i t t r t r l v c t l i r r t h c r n t c r f ' e r c t i i e t c s l . t l r e l a r g e r c q t r a t i o n t h l t n e c d s to b c s o l v e c i . r n d l h c n x r l t ' c o t r t p l c r t l r r : a n l l v s c s o l - t h c t c s t r e s u l t ) . l l t h c r c \ \ c r c ( ) n l l t \ \ o ( ) h s c r \ ' 0 t i o r t s c l l s . t t t t l o r t c u c t t ' . c r r c l l . t l r e n \ I ; . i r t d R " I . l : . r l t d tl r r ' r t , l t r . e t l lo I . l t I t t t . t t l t r - r c c t ( ) t c d t t J t l ( ) n ! . l t \ c l ) . l s

t l r e r n t l r c i a l r r u t r r r .

r n d r c r a l c q u i r l t r l n l s

l c r ,

, i - l

-

_{l t r . 7 - l}

ir,'i"

I

i r , , ,

a r _ .

l n . , a , .

I

i i l . , ' a 1 .

t '

, arc dellned as r r lt c r t l ;

( ' r , r . , ) . ( S p 1 . ( i ( 1 1 y p r . 7 , ) ) C r r n r 7 . C ( r p p : . i - ) . C ' r ) R r ) . ( l ( l t ) r , r . i ) ( 1,s1 i . ( i ( r 1 , 6 ' 1 . ) . ) .

( ' r , H : i ' { _{S ' . r ; '( i 1 1 1 ; 1 1 ' - r i )} -(-iyp; i.G(r'1;p1. i. 1

C ' 1 1 p i G ( 1 1 ; 1 , 1 . i ; C 1 , p i C { r ' , p 1 . r . 1 ,

C r ) p i . ( S n - G ( r 1 y p 1 , ) . ) ) - I

[ : s i n u e - q u a t r o n ( . ! ) . t h c i n d i c i a l n r a t n \ e q u a t l o u l b r t h e t h r e c s c l l r n t e r l e r e n c e t e s t r r c i t l r t r n g p a r a n r ! ' t e r s ( r ) R t . ( r ) R . _{a l l d ( J l , i n o r d e r to c o n s t r u c t} t h e te s l re s p o n s e c q u a l l o n s . srmple case, the t!'st responsc tirncticln could. in thcory'. be compler and Lrn*ieldy.

llr' lal the nlost c()nlrnonly used interl'erence tcst gconrelr) is the t*o-s'ell interference test geometryrr'i o - st. Oo, r l r c v c r y s i n r p l e b u t g e n e r a l c a s e o f t h e t* o - u e l l t e s t ( o n e o b s e r v a t l o n u e l l a n d o n e a c t l v e r v e l l ) . N i s u n i t y ' r t h u s \ I tt. l"he indicial response equation reduces to a 2x2 matrix-r'ector fornr gtven as:

8 a 8 c S d g e 8 f

f i o

8 h

8 i

8j

can be soh'ed for the Evcn for this seemrngly

i , , , , a , , l j r , l o , . . l

lo,, ",.j i,o,,

l

\\'hct c:

la,.

i i"l

t t

l l / r l

i l r . l i l r.:

9

l 0 a l 0 b l 0 c l 0 d c o n r 1 . ( S n r i C { r r , , . r . i ) ) I

C 1 ; p ; ) , C ( r p p 1 , _{i ).} n : . r ' ' C r r ) . G ( r o p r . i ) .

I

l . - u l u i l t , G . K . u n l l s e h u n r t n , S . ( ) , ' 1 , . - l t T I ' . ( ' l l . l o u r n u l o l l i n y i n t r r i n g u t t l . l t t h t t t t l o g . t ' l ( l ) ) 0 0 1 : I - 5

( l r r - Q . t l . . I i . l

A \ r t i . l r t 2 . 2 , 1 : . 1 , / 1 . 2 I

_ " t t , . - t _ o r . 2

i i a t . , a 2 . 2

-

_{" : . t a t. :}

)

U s r n g E q u e t r o n I I r n I i b r a t w o - s c l l s r t u a i t o n r i h c r c \ - | R . t h c p l c s s r . l r c p r o l l l c a t t h c t r b s c r r a t r r t n r r c l l R c a n b c cxprcssed rr lhe l0rnii

l l - ' . . i C r ) r , i " ( i ( r , , , , , . . i . ) l ( i ( r ' ,

, , , , , . ) . ) * u r ? [ ( ' l ) 1 , i , ( S f , + ( i ( r , , , , , , . i ) ) + l ] [ S , . * ( i ( r ' , , , . r , . . i . ) ] , 1

P r , r . r , ( l ' r , r . r , . 7 . ) l ' * R - - - . . . 1

-\

S r n r i l a r l y . u s r n q c q u a t i o n l l i n . 1 , s ' c ' c J n c \ l ) r ' L - s s t h c p r c s s u r c r c s p o n s c e r l u a t r ( ) n u t t l r c a c t t v c r r c l l a s .

P r r r , ( r r r r , , i

) =

I C , , * * ] .

l S * *

+ C i ( \ , * * . ] . ) l + 1 ] [ S , ,

+ G ( r , , , , , , . ) . ) ]

+ c r , * G ( r , , , , , . , ] , ) - C , , , . , , t " G ( r , , , , , . . i ) G ( r , , , , , , , i )

A

l l I n e q u a t i o n s l 2 a n d ll . t h e lu n c t i o n A i s g r v e n a s :

A = I ( l + C r , , ) . I S p + G ( r , , * r . _{l ) ] i i l * ( - , , * o ] . I S * * r ' G ( r ' r r R H , i )} l l - ( ' , , , ( - , , * [ i . ( i ( r t , r , r r . ; . ) l r ] l l A p p l i c a t i o n s

I f i n a t r v o - w e l l i n t e r f e r e n c e t e s t , t b r * h i c h g e n e l a l i s e d e q u a t i o n s l 2 a n d l - i a l c ' a p p l i c a b l c . * c a s s u n l c t h a t tl r c observation well is shut in, as is usually' the case, then thc paranrcter c(R appearirlg in these cquatlons bcconrcs identically zero. Under this conclition, Equations l2 representing thc plessurc responsc lirnctions at tlrc observation rvell rvould simplily to the fbllou,ing:

G ( r,r,,* , )" ; P 1 ; p p ( r 1 ; p p , _{l . )} = -

, r -

1 5

W h i l e e q u a t r o n l . - \ t b r th c a c t r v c s ' c l l s p r c s s u r c r c s p o n s c p r o f i l c s i n r p l r t r L ' s t o c q u a t t o n l ( r q n c n a s . t ( ' t ' S o u _{* G ( \ , * * . ) . ) i + l l t S t , + G ( r , , r u , ] . ) l - C D R R i G ( r , , * r , i ) ( i 1 r . , * , , , i )}

P t , ' ( r , ' , ' . 2 - ) - l ' l ) R R ' ' r ' I / r

A 'l'he

denominator of both equations l-5 antl l(r renrains as.

. l = l ( l + C u , l I S p + G ( r u r r . i " ) _{] i i l l ' C , , * * ] . I S u *} + G ( r r : l r n , i ) _{] l - f ' u r ( ' ' , r [ ) . C ( r t ) l , r { . i ) l - ]} l 1

It is perhaps interesting to note lhe synrmetry of

c o N C t _ U S t o N s

A nerv set rif ueneralised

lormulations

has

equation 14, and by extension, the entirc equation been developecl for pulse test conliguralrons \\llh

15, in (C,,,., Sp) and (C,,n,., S*,,). These sets of multiple observation r.vells. The formtrlations uses the parametcrs calt be interchanged rvithout changing concept of sottrce functions in Laplace space uith the the value or nteaning of the entire pressure principle of supc-rpositiott ilt space to account for the

response function. Equation 15 is a very elegant different locations of the

"'arious observation wc'lls demonstration of the mathematical proof of the rvithin the test dorrain. '['he new formulations allo"r' 'Reciprocity

Principle'(8'. This princrple suggests for r,r'ellbore Skin and Storage lactors to exist in eithcr that it rvould not matter rvhich of the tu'o r,rells orbclth thc active and obset'"'ation u'ells.

i n v o l v e d i n t h c r n t e l l e r c n c c t c s l i s u s c d a s t l r e Orte nrajot'advantage ttl'tlte ttc,i rlr()(lcl r.$ Ihc obsel,ation r,'ell. the pressure response nreaslred fact that, in a rnLrltiu,ell interfererrce tcst. lhc rcsp()nse

rvould be sanre. firnction for an1, of thc ohservation ivells ts rvcll spc'lt

If in the tu'o well test systeln. the sourcc- lunction out: atld can therelol'e Lr' arlalysetl rndepcridcntll rtl' G(r1,pp,).) is assunred to be the instaptancpus linc thc othcl ohservattttn wcll'; involveci in tht tt-st lhe source solution in Laplace space, these equatirtns traditronal trr'cd to tsstrnlc the line sotttce solttttott l _ 5 a n d l 6 r e a d r l y s i m p l i f y t o t h e l l l t e r f c r e n c u ' r c s p o n s e i n o r t l c r t o t y p e - c t r r v e - n r a l c l r r n t e r l e r c n c e

equations commonly published in the Pen'oleum respollse clata rvill not now be necessarv lt is llso

l l r

l t b

Falade, G.K. and Isehunx,a, S.O / LALTTECH Journal of Eugineefing and Technologt I(l) 2003: l-5 rdcas and concepts already successfully developed

lirr vanous tbrms of urteq.f.erence tests coub find their equivalents as limiting cases of the new

generahsed formulations.

R"EFERENCES

Falade. Gabriel K. " Pulse and Interference Test Desrgn. Implementation and Interpretation in Lipper Zakum" Zadco's Reservoir Engineering Report. August 1998.

Johnson, C. R., Greenkorn, R. A., and Woods, E.

G.: "Pulse Testing: A New Method Describing Reservoi.r Flow Properties Betvueen Wells", Trans.

A r M E 2 3 7 . 1 5 9 9 - t 6 0 4 , 1 9 6 6 .

Swift, S. C. and Brow& L. P.: Interference Testing for Reservoir Definition: The State of The Art".'

SPE-58091 SPE-lmproved Oil Recovery Meeting,

Tulsa. Okla., March 22-A,1976.

Bums, William A. Jr.; "New Single-Well Test for Determining Vertical Permeability". Tnos- AIME,

246.143-752.. 1969

Tongpenyai, Y. and Raghavan, R.: "The Effect of Wellboge Storage and Skin on Interference Test DaE" J . P e t . T e c h . p p l 5 l - 1 6 0 J a n . 1 9 8 1 .

Prat. M. and Scott, J. B.: "Effect of Wellbore Storage on Pulse Test response", J. Pet. Tech. pp707-709, Jan.

1975

Ramey, H^ J. Jr.: "Interference Analysis for Anisotropic Formations- A case History", J. Pet. Tech. ppl29Gl298 Oct., 1975

Falade, Gabriel K. and Brigharq William E.: " The Analysis of Single-Well Pulse Test in a Finite-Acting Slab Reservoir". SPE-50558; SPE-AIME 49th Annual Fall Meeting Houston, Oct.6-9,1974.

Ogbe, D. O. and Brighanu W. E.: "Pulse Testing With Wellbore Storage and Skin Effects", SPE Formation

Evaluation, pp2942, March 1987.

S wift, S. C. and Brown, L. P.: "Interference Testing for Reservoir Definition: The State of The Art".' SPE-5809; SPE-lmproved Oil Recovery Meeting,

Tulsa. Okla., March 22-24,1976.

,

: : , i ::$Ji,