CA2063289A1 - Method for determining electrical anisotropy of a core sample from a subterranean formation - Google Patents
Method for determining electrical anisotropy of a core sample from a subterranean formationInfo
- Publication number
- CA2063289A1 CA2063289A1 CA 2063289 CA2063289A CA2063289A1 CA 2063289 A1 CA2063289 A1 CA 2063289A1 CA 2063289 CA2063289 CA 2063289 CA 2063289 A CA2063289 A CA 2063289A CA 2063289 A1 CA2063289 A1 CA 2063289A1
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- CA
- Canada
- Prior art keywords
- core sample
- fluid
- sleeve
- core
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/043—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a granular material
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
- G01N33/241—Earth materials for hydrocarbon content
Abstract
F-6071(72)-L(PAC) Abstract of the Disclosure A method for determining electrical anisotropy of a core sample from a subterranean formation. The method comprises the steps of:
shaping said core sample into the form of a cylinder; applying a confining pressure to said core sample; saturating said core sample with a first fluid; passing a current through said fluid-saturated core sample; measuring voltages in a plurality of radial directions through said core sample; which are normal to the cylindrical axis of said core sample at each of a plurality of spaced-apart positions along said axis; determining electrical resistivities in said plurality of radial directions through said core sample from said plurality of measured voltages; and comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisotropy in said core sample. Apparatus for determining resistivity of a core sample of a subterranean formation is also disclosed.
shaping said core sample into the form of a cylinder; applying a confining pressure to said core sample; saturating said core sample with a first fluid; passing a current through said fluid-saturated core sample; measuring voltages in a plurality of radial directions through said core sample; which are normal to the cylindrical axis of said core sample at each of a plurality of spaced-apart positions along said axis; determining electrical resistivities in said plurality of radial directions through said core sample from said plurality of measured voltages; and comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisotropy in said core sample. Apparatus for determining resistivity of a core sample of a subterranean formation is also disclosed.
Description
F-6071(72)-L(PAC~ Z ~ 5 Methcd for Determi~inq Electrical AnisotroPy_of a Core Sam~ from a Subterrare~n Formation This invention relates to a method for determdndng electrical anisDtrcpy of a core sample from a subterranean formation. The inv~ntion also relates t~ apparatus for determinlng resistivity of a core sa~ple o~ a swbterranein formation.
Hydrocarbon saturation SO is generall~ deeermined frcm water saturation Sw as follows:
So = 1 - SW (1) Water ~aturation present in a subkerranean formation is typically dekermdned from interpretation of conventional electrical (i.e., resistivity) logs recQrded in a borehole drilled thr~gh the formation. Water saturation of the available pore space of the ; ; formation is determinsd fro~ the resistivity log neasurements us m g the Archie equation set forth in l'The Electrical Resistivity LLg As ~n Aid In Determu mng Some Reservoir Charac~eristics", Trans. AIME, Vol. 46, pp. 54-62, 1942, by G. E.
Archie. Ihis equation is expressed as follows:
, Sw = RW/~mRt (2) Where Sw is the fractional water saturation (i.e. free and bound wa~er of the formation expressed as a per oe nt of the available pore spa oe of the formation), ~ is the formation wa~er resistivity, ~ is the formation porosity, ~ is the formation electrical resisti~ity, n is ~he saturation exponent and m is ~he porosity or oementation e~ponent. Tlh~ Archie equation may be expressed in other ways and ~here are numerous methods in the art for determining, m~asuring or otherwi æ o~tainLng the various - . :
, . :
F-6071~72)-L(PAC) 2 ~ ~ 9 co~ponents needed to predict fractional water saturation Sw from the formation resistivity, ~ , using tha equation in any of its forms.
Archie defined two quantities that providel ~he basis or his water saturation equation (1). m e first quantity i5 the formation factor F which defines the Pffect of the rock matrix on the resistivity of water as follcws:
F Ro/ ~ ( ) where RQ - resistivity of water saturated rock and = water resistivity.
' Archie reasoned that for a given value of ~, the ~ormation factar F w~uld decrease wi~h increasing poro6ity, ~, to some exponent m:
F= 1/~ (4) is porosity exponent m has also bea~me knawn as the Archie ce~tation exponent. mus A;r~ie provided~ a useful c~harac~rization of a roc~k ~ully saturated with a con~ucting ls~ine in t~ms of the wat~r resistivi~ Rw~ poro~;ity ~ and a rock paramet~ m. It i5 important to note ~hat Ar~hie ass~ned all cor~tance to be in the brine.
q~e second quantity is the resistivity ~ndex I defined as the ratio of t:he resistivity o~ a roc3c partially sat~Yrated wit~h water and hydrocarbon, E~, to the s~u[e roc~k saturated ~ully with water, Rol as follaws:
I = Rt/Ro (5) . ~ '` :
.
Hydrocarbon saturation SO is generall~ deeermined frcm water saturation Sw as follows:
So = 1 - SW (1) Water ~aturation present in a subkerranean formation is typically dekermdned from interpretation of conventional electrical (i.e., resistivity) logs recQrded in a borehole drilled thr~gh the formation. Water saturation of the available pore space of the ; ; formation is determinsd fro~ the resistivity log neasurements us m g the Archie equation set forth in l'The Electrical Resistivity LLg As ~n Aid In Determu mng Some Reservoir Charac~eristics", Trans. AIME, Vol. 46, pp. 54-62, 1942, by G. E.
Archie. Ihis equation is expressed as follows:
, Sw = RW/~mRt (2) Where Sw is the fractional water saturation (i.e. free and bound wa~er of the formation expressed as a per oe nt of the available pore spa oe of the formation), ~ is the formation wa~er resistivity, ~ is the formation porosity, ~ is the formation electrical resisti~ity, n is ~he saturation exponent and m is ~he porosity or oementation e~ponent. Tlh~ Archie equation may be expressed in other ways and ~here are numerous methods in the art for determining, m~asuring or otherwi æ o~tainLng the various - . :
, . :
F-6071~72)-L(PAC) 2 ~ ~ 9 co~ponents needed to predict fractional water saturation Sw from the formation resistivity, ~ , using tha equation in any of its forms.
Archie defined two quantities that providel ~he basis or his water saturation equation (1). m e first quantity i5 the formation factor F which defines the Pffect of the rock matrix on the resistivity of water as follcws:
F Ro/ ~ ( ) where RQ - resistivity of water saturated rock and = water resistivity.
' Archie reasoned that for a given value of ~, the ~ormation factar F w~uld decrease wi~h increasing poro6ity, ~, to some exponent m:
F= 1/~ (4) is porosity exponent m has also bea~me knawn as the Archie ce~tation exponent. mus A;r~ie provided~ a useful c~harac~rization of a roc~k ~ully saturated with a con~ucting ls~ine in t~ms of the wat~r resistivi~ Rw~ poro~;ity ~ and a rock paramet~ m. It i5 important to note ~hat Ar~hie ass~ned all cor~tance to be in the brine.
q~e second quantity is the resistivity ~ndex I defined as the ratio of t:he resistivity o~ a roc3c partially sat~Yrated wit~h water and hydrocarbon, E~, to the s~u[e roc~k saturated ~ully with water, Rol as follaws:
I = Rt/Ro (5) . ~ '` :
.
2~
F-6071(72)-L(PAC) Archie reasoned tha~ as the water saturation decreased (i.e.
hydro OE ~on saturation increased~ the resistivity Rt and hence I
would increase to some exponen~ n:
I = 1/Swn (6) where Sw = volume of water in pores/total pore volume.
This exponent n has become known as the Archie saturation ~ t. It is again impor~ant to ncte that Archie assNm3d all oonductance to be in the krine and fur~her that all pores within the rock have the same water satNration Sw.
. .
It is these two eq~ations (4) and ~6~ for ~he forma~ion factor F
and r sistivity index I respectively that Archie csmbined to provide the water saturation expression Sw of equation ~2).
Certain log5 have provided formation resistivity ~ and porosity . Water samples provide ~he best ~alues for ~. Standard practioe is to measure rock sample resistivlties Ro and ~ for a number of water saturations and to plok the logarithm of I versus the logarithm of Sw. Archie's equations assume such a logarithmic plo~ can be fit by a strai~ht line with slo~e of -n.
~a~y oore samples are, h~wever, not ho~gencus and electrically isotropic. Fo~r such core samples, the Archi~ saturation exponent n will be strongly dependent on the direction the resistivity measurement is made. For example, a saturation exponent measured across permeability karriers within a core sample may ke one and a half times as large as if it were measured paral~el to ~he permeability barriers. qhls dl~ference can have a large detrimental e~fect on the det~xmination of hydrocarbon reserves derived from the calculated water saturation of equation (2j. It is, therefore, an object of thQ present invention to determine , .
:; ~.- , .. . . .
F-6071(72)-L(PAC) ~ 5~ 9 resistivity of a core sample that is electrically anisotrqpic and to identify the degree of anisotropy changes as the ~rine saturation of the core sample changes so that an accurate water saturation can be calc~lated frcm equation (2).
According to one ~ of the present invention there is prcvided a method for determinln~ electrical aniso~ropy of a core sample from a subterranean formation, cc~prising the ~teps of:
a) shaping s~id oore sample Lnto the form of a cylinder;
b~ applying a conLmng pressure to said care sample;
c) satuYating said core sample with a fir~t fluid;
d) passing a current through said fluid-saturated core sample;
e) measur m g volta~es i~ a plurali.ty of radial directions thrcl3h said core sample which are normal to the cylindrical axis of said oore sample ; at each of a plurality of spaced-apart positions alon~ said axis;
f) determinin~ electrical resistivities in aid plurality of radial directions thrcu3h said core sample frcm said plurality of measured voltages;
and g) comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisokropy in said core sample.
F-6071(72)-L(PAC) Preferably the step of measuring voltages co~prises:
h) establishing an initial fluid saturation within said core sample;
i) m~asNring voltages in a plurality of radial directions thrcugh said core sample, which are ~ normal t3 the cylindrical axis of said oor~ at : each of a plurality of spaced-apart positions along said axis at said initial fluid ~ on;
j) altering said fl~id saturation within said core sample a plurality of tim~s and repea~ing the electrical resistivity determinations for each ~ differing fluid satlration~
~: : Desirably ~he step of altering flu1d saturation co~prises ~he step of mcvi~g the fluid ~n said core sample in a direction parallel to said axis.
.
~ It is pre ~ that step (i) comprises:
.
k) oontacti~g the cuter surfa oe of said core sample with ~n array of electrodes at each o~ a p~urality of spaced-apart positions along ~he length of said core sample, each of said arrays being in a plane normal to said axls and the electrodes in each of said arrays being equally spaced at an even number Oæ positions abcut the outer surfa oe of said core san~ples;
. , :, . ~
:~: , ~ , - ~-:
F-6071(72)-L~P~C) ~ ~ g 1) m~asuring the voltage across each paLr of electrodes that are spaced 180 apart about said core sample; and m) utilizing the voltage measurements aGross each pair of electrades to de~ermine the electrical resistivity of the core sample in a radial direction tbrough said core sample normal to said axis between said pairs of electrodes.
m e step of shaping said core sample may be ~arried cut by CNtting the core such that the cylindrical axis of said core sa~ple is at an angle to the kedding plane of said sub~erranean formation.
After step (g) at least a portion of said first fluid may be displaced wi~h a secon~ fluid of differlng el~ctrical conductivity, and steps (d) to (g~ are repeated.
The first ~luid ma~ be el ~ ically oonduotive with said seoond fluid bein~ electrically non-oonduotive; or the first fluid may be electrically non-oonductive with said second fluid being electrically condu tive.
AYxx~liing to anokher a ~ of the invention there is provided apparatus for determinin~ resistivity of a ~ore sample of a subterranean forma~ion, ocmprising:
~) a sleeva oontainLng a cylindrical oore sample of a subterranRan formation which can be satNrated with a fluid;
F-6071(72)-L(PAC) b) means for apply ~ a current through said oore sample;
c~ means for measuring voltages in a plurality of radial directions thLo~gh said core sample normal to tha cylindri ~ axis of said oore sample in response to the flow of said curren~ thLw gh said : core ~ le; and d~ means for determininI electrical resisti~ities in said plurality of radial directions through said core samples from sai~ measured voltages.
Preferably said ~ for masuring voltages ccmprises:
e) at least ~ne electrode array e~tending throu~h said sleeve and naXing contact with ~he cuter surface of said oore sample, said array being in a plane normal to the cylindrical axis of said core sa~ple and having an even number of elec*rodes equally spaced arcund said sleeve; and f) mRans connec*ed to said electrcdes for melsNrir~
: the voltage acrcss each pair of electrodes ~hat are spaoed lB0 apart around said sleeve in response to the flow of said current through said : core sample.
Each of said electrodes may pass thrGugh said sleeve and extend outwarl frcm the inner surface of said sleeve, and be provided with a rounded end for m~king contact with the outer surface of said core sample. The rounded end is preferably spherical or semi-spherical ~ .
F--6071(72~ -L(PAC) 8 Z~5~?~J9 Desirably each of said electrodes is n~ulded irrto said sleeve.
In a preferred constru~ion ea~h of said elec~odes ca~rises:
g) a c~Tlin~ical ma~n body ~; and h) a s~erical-like end m~ f~ m3kir~ oontac~
with the ~ surface of said 003~ mple.
me er;~l men~er may be recess0d a~ace~t said main body m~r~.
Ihe erld ~er may be semi~herical with diameter greate~ ~
fflat of said main bo ~ ~ ~ Ihe flat portion of said semi~spherical end me~ber ~ay ke adjacent said ~sin body memker and n~rmal to the cylindrical axis of said main body member.
.
Preferabl~ the apparatus according to the invention inclu~es:
i~ a flui~ inlet po6itione1 in a first end of said sleeve tbrough which a se~ond fluid can be injected under pressNre in~o the f ~ end of said core sample for displacLng said:first fluid fr~n a second end of said core sample, said second fluid being immiscible with said first fluid and of opposite electrical conductance;
: j) a porous mRmker p~sitioned adjacent a seaond en~
of said sleeve tbrough which said first fluid can be discharged from the s~cond end of said core sample through said porous m~mber;
k) a fluld inlet positioned in the second end of said sleeve throu~h which said first fluid is dischar~ed frcm said sleeve after having been F-6071(72)-L(PA~) Z ~?5 ~.~5~9 displaoe d from the second end of said core sample through said porcus ~ r;
l~ a plurality of said electrode arrays dispos~d at spaoe d-a ~ positions alo~g the length of said sleeve, and m2king co~tact with the au~er surfa oe of said core sample at said spaced-apart positions, each of said arrays beLng in a plane normal to said cylindrical axis; and ; m) n~ans for applyLng a confin~ng pressure thro~gh said sleeve to said oore sa~ple. :~
~ans for may be provlded for ~ ing said determined resistivities to identify the radial direction of any electrical : . anisotropy within said core sample in the plane of each of said elec*rcde arrays anl along ~he length o~ said oore s~ple between said~electrode arrays.
Rrf o is now made to the acoompanying drawin~s, in which :
FIG. 1 illustrates prior art apparatus for carrying out resistivity determinations on core samples of aui*~ an formations;
FIG. 2 illustrates apparat~s enplo~ing electrode array~ for carrying out resistivity ~ rements on electric~lly anisokro~ic core samples of subkerranean formations in accordanoe with the present .mvention;
FIG. 3 is a cross-sectional view thra~h the apparabus of FIG. 2 showin~ in detail one of the electrode ærays of Fl.G. 2; and F-6071(72)-L(PAC) ~5~9 FIG. 4 illustrates one configuration for the electrodes of each of the electrode æ rays of FIGS. 2 and 3.
A system that has been successfully used in carrying out linear resistivity determina~ions along a ccre sample from a ~ anean formation is shown in FIG. 1 (prior art). A pressure sleeve 10, pre~erably natural or synthetic rubber, surrounds a cylindrical core sample 11 of a porous rock to ~e ~ red f~r resistivity at a plurality of fluid saturations. Positio~ed between the core sample 11 and end 12 of the pressure slee~e 10 is a porous nember 13, whi~h is p1rmearl~ to a first fluid satura~ing the core sample, kut is imperneab1e t~ a secand f~Llid used to displace the first flLud frcm the core sample. qhe sec~nd, or displacing fluid, is immiscible wi~h the first flLIid saturating the core sa~ple ~nd is of different electrical conductivity. This first saturation fluid is the wetting fluid for the porous member 13, which by way of example, may be a ceramic plate or a ~ . Sleeve 10 is placad inside a suitable pressure vessel (not ~hown) that ~an be pressurized l~p to several thousand pc~nds per square inch (several million Pa).
Typical of SLtCh pr ~ e vessels are those described in US-A-3,839,899; US-A-4,688,238; and US-A-4,379,407. m rcugh sLlch a pressure vessel a ]pressure is applied to the sleeve lO and henoe to the porous roc~ 11. m e pressure should be sufficient to ellminate any fluid annulus between the sleeve 10 and the surfaoe of the core sample. A`fluid inlet 14 and a ~luid outlet 15 fa3d into the ends 16 and 12 respectively o~ the sleeve 10. Eoth inlet 14 and outlet 15 also serve as current oonducting electrodes for pas~ing current from a source 20 tbrough the porous rock 11. A
pair of voltage electrodes 17a and 17b penekrate sleeve lO and m~ke contact wit'h the porous ro~k at spaced locations along the lengtlh of the porous rock. The voltage across ~he porous rock 11 between ~he electrodes 17a and 17b is measured by the unit 21.
`: ~
F-6071(72)-l,(PAC) 11 The core sample of porous ro~k 11 is initially fully saturated, by way of example, with an electrically conducting fluid, such as salt water, and placed under confining pr~ssure. A current is passed ~hrcugh the porGus rock and a voltage along the len3th of the porous roc~ is measured between el ~ s 17a and 17b. Such voltage measurements may be carried cut in acoordance with the di~closure of US-A-4,467,642; US-A-4,546,318; and US-A-4,686,477.
Frcm ~his v~ltage the resistance of the porous rock along its length bet~e~n electrodes 17a and 17b is determin3d using Qhm's Law~ m e resistivity, or its reciprocal conducti~ity of the porous rock is determined using ~he determined resi~tance, the length and ~he cross-sectional area of the oore. A displacing fluid suc'h as a nonconducking oil or gas, m~y then be foroel inlet 14 into end 18 of porous rock 11 t4 change the fluid saturation condition prior to the making of the ne~t resistivity m~asNreNent.
Typical of such a resistivity determin inq system of FIG. 1 are those described in US-A-4,907, 448; US-~-4 ,926,128 and US-A-4, 924 ,187 .
Havir~ naw described a typical resistivity det~mi~tion ca~ried aIt in a single direction along the axial direction of a cylin~rical core sal[ple as ~hawn in ~[G. l, the pres~nt invention of providing te~;or o~npo~ents of resistivity, or oonductivity, needed for interpretin~ elect;ric lo~s of a m~rrar~n formation with anisotrapic E~rties }: y measuring and cc~aring resistivity in a plurality of radial directions ~a~h a c~ lirx~ical core sample of the formation and normal to its c~ylir~rical axis will naw be des ~ ibed. A transversely isatrcpic cylindrical core sample of the formation is cut so ~hat the formation bedding plane is at an angle to the cylindrical axis of the cDre sa~ple. The core sample is initially saturated with an .
F-6071(72)-L(PAC) 12 electrically conducting fluid such as salt water, and placed within sleeve 10 under confining pressure representative of in-situ pressure. m e core sample is oQntacted with an array o electrodes contained by sleeve 10 at each ~f a plurality of spaoed-apart po6itions along the length of the coxe sample, such as electrode arrays A, B and C of FIG. 2 for example. Each such array ~-C lies in a plane normal to the axis O:e the care sample and the electrcdes in eaclh array are equally spaoed at an even number of positions about the sleeve 10.
FIG. 2 shows a palr of su~h electrodes Ai and Ai+N which are spaoed-apart 180 about sleeve 10 (wi~h i = 1 to N). FIG~ 3 is a cross-sectional view taken ~ h the sleeve 10 and core samp:Le 11 a~ the axial position of array A with 24 electrodes ~ -~24 being shcwn (cross-sectioning of sleeve 10 being cmitted for clarit~). As can be seen in FIG. 3 there are 12 elec*rode pairs at 180 spao0d-apart positions about sleeve 10 such as electrode ~ ~ 3 ~ ~ 4 ~ 2 and A24. A current is passed through oore sample 11 and a voltage is measured acro6s each of the Ai a~d Ai~N, ~ and Bi~N, and Ci and C ~N electrode pairs spaoed-apart 180 about the arrays A, B and C such as shown by voltage unit 22 acrc6s electrode pair ~ -~ 3 for example. These voltages as well as a voltage n~asured along the axial length of the core sample by unit 21, such as shcwn in FIG. 1, are used to determine the electrical resistivities of the oore sample bo~h along the oore sample and in t,he plurality of radial directions thro~h the e sample n~rmal to core sample axis between ~he electrodes of eac1h oorresponding electrode pair. Following these measurements, the fluid saturation in the oore sample may be altered any number of times w.it'h suc~h n~asNrements being repeated for ea~h differing fluid saturation.
':
F-6071(72)-L(PAC) 13 ~ 3 From these resistivities normal to the axis of the core sample at a plurality of positions along the axis of the core sample the desired tensor ccmponents of resistivity, or conductivity, needed for interpreting electric logs of suiberraDean formations with anisokropi~ properties are det ~ . Small core samples cut parallel and n~rmal to small but closely spaced layerings of different formation sediments show any electrical anis~rcpy that ~ght exist. Iwo oore samples cut normal and parallel to a bedding plane may not be identical in all respects ex oept for the direction of the planes relative to the cylindrical axis of the core samples and it would be dlfficult to obtain the same partial water saturations in each core sample for cc~parison n~w#~nn~ents. A single cylindrical core sample cut with the bedding plane at an angle to the axis of ~he oore sample as described above is utilizsd in accordance with the present invention to overoome such limitations.
Referring now to FIG. 4, there is shown a preferred configuration for the elec*rodes of each of the electrode arrays A-C. For purpose of example, electrcdes ~ -~3 are shown molded into a rubker sleeve 10 with cylindrical main boqy mEmbers 30-32 and spherical-l~ke end members 33-35 for making oontact wit]h the outer sur~a oe of a core sample by e~benlina outward from the inner surfaoe of sleeve 10 by a dis~ance P. AS sho~n in FIG. 4, end m~mkers 33-35 are semispherical with recessed portions, or lips, 36-38, being normal to the outer surfaoe of the cylindrical main body memkers 30-32. Su~h a semls~herical end member provides for enhanced adhesion to the rubb~r sleeve 10.
Whlle the foregoing has described a preferred embodiment of the present inven~ion, it is to be understood that vario~s mcdifications or ~hanges may be made within ~he scope of the append~d claims.
F-6071(72)-L(PAC) Archie reasoned tha~ as the water saturation decreased (i.e.
hydro OE ~on saturation increased~ the resistivity Rt and hence I
would increase to some exponen~ n:
I = 1/Swn (6) where Sw = volume of water in pores/total pore volume.
This exponent n has become known as the Archie saturation ~ t. It is again impor~ant to ncte that Archie assNm3d all oonductance to be in the krine and fur~her that all pores within the rock have the same water satNration Sw.
. .
It is these two eq~ations (4) and ~6~ for ~he forma~ion factor F
and r sistivity index I respectively that Archie csmbined to provide the water saturation expression Sw of equation ~2).
Certain log5 have provided formation resistivity ~ and porosity . Water samples provide ~he best ~alues for ~. Standard practioe is to measure rock sample resistivlties Ro and ~ for a number of water saturations and to plok the logarithm of I versus the logarithm of Sw. Archie's equations assume such a logarithmic plo~ can be fit by a strai~ht line with slo~e of -n.
~a~y oore samples are, h~wever, not ho~gencus and electrically isotropic. Fo~r such core samples, the Archi~ saturation exponent n will be strongly dependent on the direction the resistivity measurement is made. For example, a saturation exponent measured across permeability karriers within a core sample may ke one and a half times as large as if it were measured paral~el to ~he permeability barriers. qhls dl~ference can have a large detrimental e~fect on the det~xmination of hydrocarbon reserves derived from the calculated water saturation of equation (2j. It is, therefore, an object of thQ present invention to determine , .
:; ~.- , .. . . .
F-6071(72)-L(PAC) ~ 5~ 9 resistivity of a core sample that is electrically anisotrqpic and to identify the degree of anisotropy changes as the ~rine saturation of the core sample changes so that an accurate water saturation can be calc~lated frcm equation (2).
According to one ~ of the present invention there is prcvided a method for determinln~ electrical aniso~ropy of a core sample from a subterranean formation, cc~prising the ~teps of:
a) shaping s~id oore sample Lnto the form of a cylinder;
b~ applying a conLmng pressure to said care sample;
c) satuYating said core sample with a fir~t fluid;
d) passing a current through said fluid-saturated core sample;
e) measur m g volta~es i~ a plurali.ty of radial directions thrcl3h said core sample which are normal to the cylindrical axis of said oore sample ; at each of a plurality of spaced-apart positions alon~ said axis;
f) determinin~ electrical resistivities in aid plurality of radial directions thrcu3h said core sample frcm said plurality of measured voltages;
and g) comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisokropy in said core sample.
F-6071(72)-L(PAC) Preferably the step of measuring voltages co~prises:
h) establishing an initial fluid saturation within said core sample;
i) m~asNring voltages in a plurality of radial directions thrcugh said core sample, which are ~ normal t3 the cylindrical axis of said oor~ at : each of a plurality of spaced-apart positions along said axis at said initial fluid ~ on;
j) altering said fl~id saturation within said core sample a plurality of tim~s and repea~ing the electrical resistivity determinations for each ~ differing fluid satlration~
~: : Desirably ~he step of altering flu1d saturation co~prises ~he step of mcvi~g the fluid ~n said core sample in a direction parallel to said axis.
.
~ It is pre ~ that step (i) comprises:
.
k) oontacti~g the cuter surfa oe of said core sample with ~n array of electrodes at each o~ a p~urality of spaced-apart positions along ~he length of said core sample, each of said arrays being in a plane normal to said axls and the electrodes in each of said arrays being equally spaced at an even number Oæ positions abcut the outer surfa oe of said core san~ples;
. , :, . ~
:~: , ~ , - ~-:
F-6071(72)-L~P~C) ~ ~ g 1) m~asuring the voltage across each paLr of electrodes that are spaced 180 apart about said core sample; and m) utilizing the voltage measurements aGross each pair of electrades to de~ermine the electrical resistivity of the core sample in a radial direction tbrough said core sample normal to said axis between said pairs of electrodes.
m e step of shaping said core sample may be ~arried cut by CNtting the core such that the cylindrical axis of said core sa~ple is at an angle to the kedding plane of said sub~erranean formation.
After step (g) at least a portion of said first fluid may be displaced wi~h a secon~ fluid of differlng el~ctrical conductivity, and steps (d) to (g~ are repeated.
The first ~luid ma~ be el ~ ically oonduotive with said seoond fluid bein~ electrically non-oonduotive; or the first fluid may be electrically non-oonductive with said second fluid being electrically condu tive.
AYxx~liing to anokher a ~ of the invention there is provided apparatus for determinin~ resistivity of a ~ore sample of a subterranean forma~ion, ocmprising:
~) a sleeva oontainLng a cylindrical oore sample of a subterranRan formation which can be satNrated with a fluid;
F-6071(72)-L(PAC) b) means for apply ~ a current through said oore sample;
c~ means for measuring voltages in a plurality of radial directions thLo~gh said core sample normal to tha cylindri ~ axis of said oore sample in response to the flow of said curren~ thLw gh said : core ~ le; and d~ means for determininI electrical resisti~ities in said plurality of radial directions through said core samples from sai~ measured voltages.
Preferably said ~ for masuring voltages ccmprises:
e) at least ~ne electrode array e~tending throu~h said sleeve and naXing contact with ~he cuter surface of said oore sample, said array being in a plane normal to the cylindrical axis of said core sa~ple and having an even number of elec*rodes equally spaced arcund said sleeve; and f) mRans connec*ed to said electrcdes for melsNrir~
: the voltage acrcss each pair of electrodes ~hat are spaoed lB0 apart around said sleeve in response to the flow of said current through said : core sample.
Each of said electrodes may pass thrGugh said sleeve and extend outwarl frcm the inner surface of said sleeve, and be provided with a rounded end for m~king contact with the outer surface of said core sample. The rounded end is preferably spherical or semi-spherical ~ .
F--6071(72~ -L(PAC) 8 Z~5~?~J9 Desirably each of said electrodes is n~ulded irrto said sleeve.
In a preferred constru~ion ea~h of said elec~odes ca~rises:
g) a c~Tlin~ical ma~n body ~; and h) a s~erical-like end m~ f~ m3kir~ oontac~
with the ~ surface of said 003~ mple.
me er;~l men~er may be recess0d a~ace~t said main body m~r~.
Ihe erld ~er may be semi~herical with diameter greate~ ~
fflat of said main bo ~ ~ ~ Ihe flat portion of said semi~spherical end me~ber ~ay ke adjacent said ~sin body memker and n~rmal to the cylindrical axis of said main body member.
.
Preferabl~ the apparatus according to the invention inclu~es:
i~ a flui~ inlet po6itione1 in a first end of said sleeve tbrough which a se~ond fluid can be injected under pressNre in~o the f ~ end of said core sample for displacLng said:first fluid fr~n a second end of said core sample, said second fluid being immiscible with said first fluid and of opposite electrical conductance;
: j) a porous mRmker p~sitioned adjacent a seaond en~
of said sleeve tbrough which said first fluid can be discharged from the s~cond end of said core sample through said porous m~mber;
k) a fluld inlet positioned in the second end of said sleeve throu~h which said first fluid is dischar~ed frcm said sleeve after having been F-6071(72)-L(PA~) Z ~?5 ~.~5~9 displaoe d from the second end of said core sample through said porcus ~ r;
l~ a plurality of said electrode arrays dispos~d at spaoe d-a ~ positions alo~g the length of said sleeve, and m2king co~tact with the au~er surfa oe of said core sample at said spaced-apart positions, each of said arrays beLng in a plane normal to said cylindrical axis; and ; m) n~ans for applyLng a confin~ng pressure thro~gh said sleeve to said oore sa~ple. :~
~ans for may be provlded for ~ ing said determined resistivities to identify the radial direction of any electrical : . anisotropy within said core sample in the plane of each of said elec*rcde arrays anl along ~he length o~ said oore s~ple between said~electrode arrays.
Rrf o is now made to the acoompanying drawin~s, in which :
FIG. 1 illustrates prior art apparatus for carrying out resistivity determinations on core samples of aui*~ an formations;
FIG. 2 illustrates apparat~s enplo~ing electrode array~ for carrying out resistivity ~ rements on electric~lly anisokro~ic core samples of subkerranean formations in accordanoe with the present .mvention;
FIG. 3 is a cross-sectional view thra~h the apparabus of FIG. 2 showin~ in detail one of the electrode ærays of Fl.G. 2; and F-6071(72)-L(PAC) ~5~9 FIG. 4 illustrates one configuration for the electrodes of each of the electrode æ rays of FIGS. 2 and 3.
A system that has been successfully used in carrying out linear resistivity determina~ions along a ccre sample from a ~ anean formation is shown in FIG. 1 (prior art). A pressure sleeve 10, pre~erably natural or synthetic rubber, surrounds a cylindrical core sample 11 of a porous rock to ~e ~ red f~r resistivity at a plurality of fluid saturations. Positio~ed between the core sample 11 and end 12 of the pressure slee~e 10 is a porous nember 13, whi~h is p1rmearl~ to a first fluid satura~ing the core sample, kut is imperneab1e t~ a secand f~Llid used to displace the first flLud frcm the core sample. qhe sec~nd, or displacing fluid, is immiscible wi~h the first flLIid saturating the core sa~ple ~nd is of different electrical conductivity. This first saturation fluid is the wetting fluid for the porous member 13, which by way of example, may be a ceramic plate or a ~ . Sleeve 10 is placad inside a suitable pressure vessel (not ~hown) that ~an be pressurized l~p to several thousand pc~nds per square inch (several million Pa).
Typical of SLtCh pr ~ e vessels are those described in US-A-3,839,899; US-A-4,688,238; and US-A-4,379,407. m rcugh sLlch a pressure vessel a ]pressure is applied to the sleeve lO and henoe to the porous roc~ 11. m e pressure should be sufficient to ellminate any fluid annulus between the sleeve 10 and the surfaoe of the core sample. A`fluid inlet 14 and a ~luid outlet 15 fa3d into the ends 16 and 12 respectively o~ the sleeve 10. Eoth inlet 14 and outlet 15 also serve as current oonducting electrodes for pas~ing current from a source 20 tbrough the porous rock 11. A
pair of voltage electrodes 17a and 17b penekrate sleeve lO and m~ke contact wit'h the porous ro~k at spaced locations along the lengtlh of the porous rock. The voltage across ~he porous rock 11 between ~he electrodes 17a and 17b is measured by the unit 21.
`: ~
F-6071(72)-l,(PAC) 11 The core sample of porous ro~k 11 is initially fully saturated, by way of example, with an electrically conducting fluid, such as salt water, and placed under confining pr~ssure. A current is passed ~hrcugh the porGus rock and a voltage along the len3th of the porous roc~ is measured between el ~ s 17a and 17b. Such voltage measurements may be carried cut in acoordance with the di~closure of US-A-4,467,642; US-A-4,546,318; and US-A-4,686,477.
Frcm ~his v~ltage the resistance of the porous rock along its length bet~e~n electrodes 17a and 17b is determin3d using Qhm's Law~ m e resistivity, or its reciprocal conducti~ity of the porous rock is determined using ~he determined resi~tance, the length and ~he cross-sectional area of the oore. A displacing fluid suc'h as a nonconducking oil or gas, m~y then be foroel inlet 14 into end 18 of porous rock 11 t4 change the fluid saturation condition prior to the making of the ne~t resistivity m~asNreNent.
Typical of such a resistivity determin inq system of FIG. 1 are those described in US-A-4,907, 448; US-~-4 ,926,128 and US-A-4, 924 ,187 .
Havir~ naw described a typical resistivity det~mi~tion ca~ried aIt in a single direction along the axial direction of a cylin~rical core sal[ple as ~hawn in ~[G. l, the pres~nt invention of providing te~;or o~npo~ents of resistivity, or oonductivity, needed for interpretin~ elect;ric lo~s of a m~rrar~n formation with anisotrapic E~rties }: y measuring and cc~aring resistivity in a plurality of radial directions ~a~h a c~ lirx~ical core sample of the formation and normal to its c~ylir~rical axis will naw be des ~ ibed. A transversely isatrcpic cylindrical core sample of the formation is cut so ~hat the formation bedding plane is at an angle to the cylindrical axis of the cDre sa~ple. The core sample is initially saturated with an .
F-6071(72)-L(PAC) 12 electrically conducting fluid such as salt water, and placed within sleeve 10 under confining pressure representative of in-situ pressure. m e core sample is oQntacted with an array o electrodes contained by sleeve 10 at each ~f a plurality of spaoed-apart po6itions along the length of the coxe sample, such as electrode arrays A, B and C of FIG. 2 for example. Each such array ~-C lies in a plane normal to the axis O:e the care sample and the electrcdes in eaclh array are equally spaoed at an even number of positions about the sleeve 10.
FIG. 2 shows a palr of su~h electrodes Ai and Ai+N which are spaoed-apart 180 about sleeve 10 (wi~h i = 1 to N). FIG~ 3 is a cross-sectional view taken ~ h the sleeve 10 and core samp:Le 11 a~ the axial position of array A with 24 electrodes ~ -~24 being shcwn (cross-sectioning of sleeve 10 being cmitted for clarit~). As can be seen in FIG. 3 there are 12 elec*rode pairs at 180 spao0d-apart positions about sleeve 10 such as electrode ~ ~ 3 ~ ~ 4 ~ 2 and A24. A current is passed through oore sample 11 and a voltage is measured acro6s each of the Ai a~d Ai~N, ~ and Bi~N, and Ci and C ~N electrode pairs spaoed-apart 180 about the arrays A, B and C such as shown by voltage unit 22 acrc6s electrode pair ~ -~ 3 for example. These voltages as well as a voltage n~asured along the axial length of the core sample by unit 21, such as shcwn in FIG. 1, are used to determine the electrical resistivities of the oore sample bo~h along the oore sample and in t,he plurality of radial directions thro~h the e sample n~rmal to core sample axis between ~he electrodes of eac1h oorresponding electrode pair. Following these measurements, the fluid saturation in the oore sample may be altered any number of times w.it'h suc~h n~asNrements being repeated for ea~h differing fluid saturation.
':
F-6071(72)-L(PAC) 13 ~ 3 From these resistivities normal to the axis of the core sample at a plurality of positions along the axis of the core sample the desired tensor ccmponents of resistivity, or conductivity, needed for interpreting electric logs of suiberraDean formations with anisokropi~ properties are det ~ . Small core samples cut parallel and n~rmal to small but closely spaced layerings of different formation sediments show any electrical anis~rcpy that ~ght exist. Iwo oore samples cut normal and parallel to a bedding plane may not be identical in all respects ex oept for the direction of the planes relative to the cylindrical axis of the core samples and it would be dlfficult to obtain the same partial water saturations in each core sample for cc~parison n~w#~nn~ents. A single cylindrical core sample cut with the bedding plane at an angle to the axis of ~he oore sample as described above is utilizsd in accordance with the present invention to overoome such limitations.
Referring now to FIG. 4, there is shown a preferred configuration for the elec*rodes of each of the electrode arrays A-C. For purpose of example, electrcdes ~ -~3 are shown molded into a rubker sleeve 10 with cylindrical main boqy mEmbers 30-32 and spherical-l~ke end members 33-35 for making oontact wit]h the outer sur~a oe of a core sample by e~benlina outward from the inner surfaoe of sleeve 10 by a dis~ance P. AS sho~n in FIG. 4, end m~mkers 33-35 are semispherical with recessed portions, or lips, 36-38, being normal to the outer surfaoe of the cylindrical main body memkers 30-32. Su~h a semls~herical end member provides for enhanced adhesion to the rubb~r sleeve 10.
Whlle the foregoing has described a preferred embodiment of the present inven~ion, it is to be understood that vario~s mcdifications or ~hanges may be made within ~he scope of the append~d claims.
Claims (20)
1. A method for determining electrical anistropy of a core sample from a subterranean formation, comprising the steps of:
a) shaping said core sample into the form of a cylinder;
b) applying a confining pressure to said core sample c) saturating said core sample with a first fluid;
d) passing a current through said fluid-saturated core sample;
e) measuring voltages in a plurality of radial directions through said core sample which are normal to the cylindrical axis of said core sample at each of a plurality of spaced-apart positions along said axis;
f) determining electrical resistivities in said plurality of radial directions through said core sample from said plurality of measured voltages;
and g) comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisotropy in said core sample.
a) shaping said core sample into the form of a cylinder;
b) applying a confining pressure to said core sample c) saturating said core sample with a first fluid;
d) passing a current through said fluid-saturated core sample;
e) measuring voltages in a plurality of radial directions through said core sample which are normal to the cylindrical axis of said core sample at each of a plurality of spaced-apart positions along said axis;
f) determining electrical resistivities in said plurality of radial directions through said core sample from said plurality of measured voltages;
and g) comparing each of said determined electrical resistivities to identify the radial direction of any electrical anisotropy in said core sample.
2. A method according to claim 1 wherein the step of measuring voltages comprises:
F-6071(72)-L(PAC) 15 h) establishing an initial fluid saturation within said core sample;
i) measuring voltages in a plurality of radial directions through said core sample, which are normal to the cylindrical axis of said core at each of a plurality of spaced-apart positions along said axis at said initial fluid saturation;
and j) altering said fluid saturation within said core sample a plurality of times and repeating the electrical resistivity determinations for each differing fluid saturation.
F-6071(72)-L(PAC) 15 h) establishing an initial fluid saturation within said core sample;
i) measuring voltages in a plurality of radial directions through said core sample, which are normal to the cylindrical axis of said core at each of a plurality of spaced-apart positions along said axis at said initial fluid saturation;
and j) altering said fluid saturation within said core sample a plurality of times and repeating the electrical resistivity determinations for each differing fluid saturation.
3. A method according to claim 2 wherein the step of altering fluid saturation comprises the step of moving the fluid in said core sample in a direction parallel to said axis.
4. A method according to claim 2 or 3 wherein step (i) comprises:
a) contacting the outer surface of said core sample with an array of electrodes at each of a plurality of spaced-apart positions along the length of said core sample, each of said arrays being in a plane normal to said axis and the electrodes m each of said arrays being equally spaced at an even number of positions about the outer surface of said core samples;
b) measuring the voltage across each pair of electrodes that are spaced 180° apart about said core sample; and F-6071(72)-L(PAC) c) utilizing the voltage measurements across each pair of electrodes to determine the electrical resistivity of the core sample in a radial direction through said core sample normal to said axis between said pairs of electrodes.
a) contacting the outer surface of said core sample with an array of electrodes at each of a plurality of spaced-apart positions along the length of said core sample, each of said arrays being in a plane normal to said axis and the electrodes m each of said arrays being equally spaced at an even number of positions about the outer surface of said core samples;
b) measuring the voltage across each pair of electrodes that are spaced 180° apart about said core sample; and F-6071(72)-L(PAC) c) utilizing the voltage measurements across each pair of electrodes to determine the electrical resistivity of the core sample in a radial direction through said core sample normal to said axis between said pairs of electrodes.
5. A method according to any proceeding claim wherein the step of shaping said core sample is carried cut by cutting the core such that the cylindrical axis of said core sample is at an angle to the bedding plane of said subterranean formation.
6. A method according to any preceding claim wherein after step (g) at least a portion of said first fluid is displaced with a second fluid of differing electrical conductivity, and steps (d) to (g) are repeated.
7. A method according to claim 6 wherein said first fluid is electrically conductive and said second fluid is electrically non-conductive.
8. A method according to claim 6 wherein said first fluid is electrically non-conductive and said second fluid is electrically conductive.
9. Apparatus for determining resistivity of a core sample of a subterranean formation, comprising:
a) a sleeve containing a cylindrical core sample of a subterranean formation which can be saturated with a fluid;
b) means for applying a current through said core sample;
F-6071(72)-L(PAC) c) means for measuring voltages in a plurality of radial directions through said core sample normal to the cylindrical axis of said core sample in response to the flow of said current through said core sample; and d) means for determining electrical resistivities in said plurality of radial directions through said core samples from said measured voltages.
a) a sleeve containing a cylindrical core sample of a subterranean formation which can be saturated with a fluid;
b) means for applying a current through said core sample;
F-6071(72)-L(PAC) c) means for measuring voltages in a plurality of radial directions through said core sample normal to the cylindrical axis of said core sample in response to the flow of said current through said core sample; and d) means for determining electrical resistivities in said plurality of radial directions through said core samples from said measured voltages.
10. Apparatus according to claim 9 wherein said means for measuring voltages comprises:
e) at least one electrode array extending through said sleeve and making contact with the outer surface of said core sample, said array being in a plane normal to the cylindrical axis of said core sample and having an even number of electrodes equally spaced around said sleeve; and f) means connected to said electrodes for measuring the voltage across each pair of electrodes that are spaced 180° apart around said sleeve in response to the flow of said current through said core sample.
e) at least one electrode array extending through said sleeve and making contact with the outer surface of said core sample, said array being in a plane normal to the cylindrical axis of said core sample and having an even number of electrodes equally spaced around said sleeve; and f) means connected to said electrodes for measuring the voltage across each pair of electrodes that are spaced 180° apart around said sleeve in response to the flow of said current through said core sample.
11. Apparatus according to claim 10 wherein each of said electrodes passes through said sleeve and extends outward from the inner surface of said sleeve with a rounded end for making contact with the outer surface of said core sample.
12. Apparatus according to claim 11 wherein each of said electrodes is molded into said sleeve.
F-6071(72)-L(PAC)
F-6071(72)-L(PAC)
13. Apparatus according to claim 11 or 12 wherein said rounded end is spherical.
14. Apparatus according to claim 11 or 12 wherein said rounded end is semi-spherical.
15. Apparatus according to any of claims 10 to 14 wherein each of said electrodes comprises:
g) a cylindrical main body member; and h) a spherical-like end member for making contact with the outer surface of said core sample.
g) a cylindrical main body member; and h) a spherical-like end member for making contact with the outer surface of said core sample.
16. Apparatus according to claim 15 wherein said end member is recessed adjacent said main body member.
17. Apparatus according to claim 15 or 16 wherein said end member is semi-spherical with diameter greater than that of said main body member.
18. Apparatus of claim 17 wherein the flat portion of said semi-spherical end member is adjacent said main body member and normal to the cylindrical axis of said main body member.
19. Apparatus according to any of claims 10 to 15 further comprising:
i) a fluid inlet positioned in a first end of said sleeve through which a second fluid can be injected under pressure into the first end of said core sample for displacing said first fluid from a second end of said core sample, said second fluid F-6071(72)-L(PAC) being immiscible with said first fluid and of opposite electrical conductance;
j) a porous member positioned adjacent a second end of said sleeve through which said first fluid can be discharged from the second end of said core sample through said porous member;
k) a fluid inlet positioned in the second end of said sleeve through which said first fluid is discharged from said sleeve after having been displaced from the second end of said core sample through said porous member;
l) a plurality of said electrode arrays disposed at spaced-apart positions along the length of said sleeve, and making contact with the outer surface of said core sample at said spaced-apart positions, each of said arrays being in a plane normal to said cylindrical axis; and m) means for applying a confining pressure through said sleeve to said core sample.
i) a fluid inlet positioned in a first end of said sleeve through which a second fluid can be injected under pressure into the first end of said core sample for displacing said first fluid from a second end of said core sample, said second fluid F-6071(72)-L(PAC) being immiscible with said first fluid and of opposite electrical conductance;
j) a porous member positioned adjacent a second end of said sleeve through which said first fluid can be discharged from the second end of said core sample through said porous member;
k) a fluid inlet positioned in the second end of said sleeve through which said first fluid is discharged from said sleeve after having been displaced from the second end of said core sample through said porous member;
l) a plurality of said electrode arrays disposed at spaced-apart positions along the length of said sleeve, and making contact with the outer surface of said core sample at said spaced-apart positions, each of said arrays being in a plane normal to said cylindrical axis; and m) means for applying a confining pressure through said sleeve to said core sample.
20. Apparatus according to claim 16 further including means for comparing said determined resistivities to identify the radial direction of any electrical anisotropy within said core sample in the plane of each of said electrode arrays and along the length of said core sample between said electrode arrays.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/671,340 US5105154A (en) | 1991-03-19 | 1991-03-19 | Apparatus for measuring radial resistivities in cylindrical core samples of porous rock |
| US671,249 | 1991-03-19 | ||
| US07/671,249 US5093623A (en) | 1991-03-19 | 1991-03-19 | Method for determining electrical anisotrophy from radial resistivities in cylindrical core samples of porous rock |
| US671,340 | 1991-03-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2063289A1 true CA2063289A1 (en) | 1992-09-20 |
Family
ID=27100501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2063289 Abandoned CA2063289A1 (en) | 1991-03-19 | 1992-03-18 | Method for determining electrical anisotropy of a core sample from a subterranean formation |
Country Status (5)
| Country | Link |
|---|---|
| AU (1) | AU657518B2 (en) |
| CA (1) | CA2063289A1 (en) |
| DE (1) | DE4208953A1 (en) |
| GB (1) | GB2254703B (en) |
| NO (1) | NO921058L (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2781573B1 (en) * | 1998-07-24 | 2000-08-25 | Inst Francais Du Petrole | METHOD OF RAPID MEASUREMENT OF THE RESISTIVITY INDEX OF SOLID SAMPLES SUCH AS ROCKS |
| DE102016116452B4 (en) | 2016-08-24 | 2024-05-08 | Leibniz-Institut für Angewandte Geophysik | SIP measuring cell |
| CN108896742B (en) * | 2018-08-01 | 2023-09-29 | 中国华能集团有限公司 | System for quantitatively analyzing shale anisotropy and application method thereof |
| CN114720518A (en) * | 2021-01-06 | 2022-07-08 | 中国石油天然气股份有限公司 | Core holder, rock measurement system and resistance measurement method of core |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2802172A (en) * | 1953-07-16 | 1957-08-06 | Socony Mobil Oil Co Inc | Core sample resistivity cell |
| US4907448A (en) * | 1989-02-13 | 1990-03-13 | Mobil Oil Corporation | Apparatus for measuring resistivity of porous rock |
| US4926128A (en) * | 1989-02-13 | 1990-05-15 | Mobil Oil Corporation | Method for utilizing measured resistivities of porous rock under differing fluid saturations to identify fluid distribution equilibrium |
| US4924187A (en) * | 1989-06-12 | 1990-05-08 | Mobil Oil Corporation | Method for measuring electrical anisotrophy of a core sample from a subterranean formation |
| GB2243690A (en) * | 1990-05-05 | 1991-11-06 | Natural Environment Res | Apparatus and method for assessing geophysical characteristics of a core sample |
-
1992
- 1992-02-24 GB GB9203883A patent/GB2254703B/en not_active Expired - Fee Related
- 1992-03-12 AU AU12876/92A patent/AU657518B2/en not_active Ceased
- 1992-03-18 NO NO92921058A patent/NO921058L/en unknown
- 1992-03-18 CA CA 2063289 patent/CA2063289A1/en not_active Abandoned
- 1992-03-19 DE DE19924208953 patent/DE4208953A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB9203883D0 (en) | 1992-04-08 |
| NO921058L (en) | 1992-09-21 |
| AU1287692A (en) | 1992-09-24 |
| GB2254703B (en) | 1995-02-22 |
| AU657518B2 (en) | 1995-03-16 |
| NO921058D0 (en) | 1992-03-18 |
| GB2254703A (en) | 1992-10-14 |
| DE4208953A1 (en) | 1992-09-24 |
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