Patent EP0206706A2 successfully refreshed from Google Patents.
EP0206706A2
Expired / Lapsed
EP
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Measurement of electrical resistivity in borehole
Assignee: Halliburton Co
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Filing: 1986-06-16
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Granted: —
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Expires: 2006-06-16
Abstract
Abstract Apparatus and method for investigating the electrical resistivity of an earth formation in the vicinity of a borehole employ an array of electrodes including a central current electrode (Ao) and focussing current electrodes (A3, A4, A 3 ', A4') above and below the central current electrode. A focussed resistivity measurement current is caused to flow from the current electrodes through the earth formation, the amplitude of the current flowing through upper and lower current electrodes being independently controlled by voltages measured by electrodes (M i , M 2 , M 3 , M 1 ', M2', M 3 ') above and below the central electrode, respectively. Voltage and current measurement are provided for determining the resistivity of the earth formation.
Inventors
- 👤 Robert Anthony Moore
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 20:26
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/20; G01V3/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
210 words
Apparatus for investigating the electrical resistivity of materials in the vicinity of the apparatus in a borehole, comprising: (i) an array of electrodes including: a central current electrode A o ; at least one pair of current electrodes including an upper current electrode (A3, A4) spaced above said central current electrode A o and a lower current electrode (A 3 ', A 4 ') spaced below said central current electrode A o ; upper voltage measurement electrodes (M 1 , M 2 , M 3 ) located above said central current electrode A o ; and lower voltage measurement electrodes (M 1 ', M 2 ', M 3 ') located below said central current electrode A o ; (ii) current driving means for producing current flow in said materials in the vicinity of the apparatus and for focusing said current flow including: means (32; 84) responsive to said upper measurement electrodes for driving said upper current electrode; and means (48; 90) responsive to said lower measurement electrodes for driving said lower current electrode independently of said upper electrode; and (iii) means for determining resistivity of said materials from measured current flow through the central current electrode and from a voltage measured at at least one of said voltage measurement electrodes.
Claim 2
Dependent Claim
210 words
Apparatus for investigating the electrical resistivity of materials in the vicinity of the apparatus in a borehole, comprising: (i) an array of electrodes including: a central current electrode A o ; at least one pair of current electrodes including an upper current electrode (A3, A4) spaced above said central current electrode A o and a lower current electrode (A 3 ', A 4 ') spaced below said central current electrode A o ; upper voltage measurement electrodes (M 1 , M 2 , M 3 ) located above said central current electrode A o ; and lower voltage measurement electrodes (M 1 ', M 2 ', M 3 ') located below said central current electrode A o ; (ii) current driving means for producing current flow in said materials in the vicinity of the apparatus and for focusing said current flow including: means (32; 84) responsive to said upper measurement electrodes for driving said upper current electrode; and means (48; 90) responsive to said lower measurement electrodes for driving said lower current electrode independently of said upper electrode; and (iii) means for determining resistivity of said materials from measured current flow through the central current electrode and from a voltage measured at at least one of said voltage measurement electrodes.
Claim 3
Dependent Claim
108 words
Apparatus according to claim 1, wherein said current electrodes include: a first pair of current electrodes comprising an electrode A3 spaced above said central current electrode A o , and an electrode A 3 ' spaced below said central current electrode A D ; a second pair of current electrodes comprising an electrode A4 spaced above said electrode A 3 , and an electrode A 4 ' spaced below said electrode A 3 '; and wherein said upper voltage measurement electrodes are located between said electrode A o and electrode A4; and said lower voltage measurement electrodes are located between said electrode A and electrode A 4 '.
Claim 4
Dependent Claim
72 words
Apparatus according to claim 2, wherein said current driving means drives electrodes A , A3 and A 3 ' synchronously at a frequency F S whereby current flow is produced from electrodes A o and A3 to electrode A4 and from electrodes A o and A 3 ' to electrode A 4 ', thereby to provide a shallow focus for measurement current produced in the materials in the vicinity of the apparatus.
Claim 5
Dependent Claim
63 words
Apparatus according to claim 2 or 3, further comprising a remote electrode (22) located remote from said electrode array, and wherein said current driving means drives electrodes A , A3, A 3 ', A 4 and A 4 ' synchronously at a frequency F D to provide a deep focus for measurement current produced in the materials in the vicinity of the apparatus.
Claim 6
Dependent Claim
30 words
Apparatus according to claim 4, wherein the current drive means are so arranged that the frequency F S is harmonically related to and greater than the frequency F D .
Claim 7
Dependent Claim
41 words
Apparatus according to claim 2,3,4 or 5, wherein said current driving means includes an A o current supply coupled to a first transformer, said first transformer having a winding connected between the electrode A o and the electrode A 4 .
Claim 8
Independent Claim
259 words
A method for investigating the electrical resistivity of materials in the vicinity of a borehole with a well logging tool including an electrode array having a central current electrode A , at least one pair of current electrodes including an upper current electrode (A3, A4) spaced above said central current electrode A o and a lower current electrode (A 3 ', A 4 ') spaced below said central current electrode A , upper voltage measurement electrodes (M 1 , M 2 , M 3 ) located above said central current electrode A , and lower voltage measurement electrodes (M 1 ', M 2 1 , M 3 1 ) located below said central current electrode A , comprising the steps of: (i) driving said A o electrode to produce a survey current flow in said materials in the vicinity of the borehole; (ii) driving said upper current electrode and said lower current electrode synchronously with said A o electrode to produce upper and lower focussing currents, respectively, for focussing said survey current; (iii) controlling the amplitude of said upper focussing current in response to the voltage measurement from said upper voltage measurement electrodes; (iv) controlling the amplitude of said lower focussing current in response to the voltage measurement from said lower voltage measurement electrodes, said lower focussing current being controlled independently of said upper focussing current; and (v) determining the resistivity of said materials from measured current flow from the central current electrode A o and from a voltage measured at at least one of said voltage measurement electrodes.
Claim 9
Independent Claim
259 words
A method for investigating the electrical resistivity of materials in the vicinity of a borehole with a well logging tool including an electrode array having a central current electrode A , at least one pair of current electrodes including an upper current electrode (A3, A4) spaced above said central current electrode A o and a lower current electrode (A 3 ', A 4 ') spaced below said central current electrode A , upper voltage measurement electrodes (M 1 , M 2 , M 3 ) located above said central current electrode A , and lower voltage measurement electrodes (M 1 ', M 2 1 , M 3 1 ) located below said central current electrode A , comprising the steps of: (i) driving said A o electrode to produce a survey current flow in said materials in the vicinity of the borehole; (ii) driving said upper current electrode and said lower current electrode synchronously with said A o electrode to produce upper and lower focussing currents, respectively, for focussing said survey current; (iii) controlling the amplitude of said upper focussing current in response to the voltage measurement from said upper voltage measurement electrodes; (iv) controlling the amplitude of said lower focussing current in response to the voltage measurement from said lower voltage measurement electrodes, said lower focussing current being controlled independently of said upper focussing current; and (v) determining the resistivity of said materials from measured current flow from the central current electrode A o and from a voltage measured at at least one of said voltage measurement electrodes.
Claim 10
Dependent Claim
176 words
A method of claim 7, wherein said at least one pair of current electrodes includes a first pair of current electrodes comprising an electrode A 3 spaced above said central current electrode A and an electrode 0 A 3 ' spaced below said central current electrode A o , and a second pair of current electrodes comprising an electrode A4 spaced above said electrode A3 and an electrode A 4 ' spaced below said electrode A 3 1 , and said upper voltage measurement electrodes are located between said electrode A o and said electrode A 4 and said lower voltage measurement electrodes are located between said electrode A o and said electrode A 4 '; and wherein said electrodes A o , A3 and A 3 ' are driven synchronously at a frequency F S whereby current flow is produced from electrodes A and A3 to electrode A4 and from electrodes A o and A 3 ' to electrode A 4 ', thereby to provide a shallow focus for survey current produced in said materials.
Claim 11
Dependent Claim
54 words
A method according to claim 8, wherein a remote electrode (22) is located remote from said electrode array, and wherein said electrodes A o , A 3 , A 3 ', A 4 and A 4 ' are driven synchronously at a frequency F D to provide a deep focus for said survey current.
Claim 12
Dependent Claim
24 words
A method according to claim 8 or 9, wherein the frequency F S is harmonically related to and greater than frequency F D .
References Cited (Backward Citations)
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