Improved resistivity measurement using a galvanic tool

Patent metadata

Field	Value
Publication number	US-2016349405-A1
Application number	US-201515112760-A
Country	US
Kind code	A1
Filing date	Oct 1, 2015
Priority date	Oct 10, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

An example calibration method for a galvanic tool may include determining an internal coupling impedance between at least two electrodes of the galvanic tool, and inputting the determined internal coupling impedances into an equation used to evaluate the response of the tool. Voltage and current measurements may be generated from the galvanic tool using a calibration device. A leakage current value through at least one of the two electrodes may be determined based, at least in part, on the voltage and current measurements and the equation. The leakage current may be stored.

First claim

What is claimed is:

1 . A calibration method for a galvanic tool, comprising:
determining an internal coupling impedance between at least two electrodes of the galvanic tool; inputting the determined internal coupling impedances into an equation used to evaluate the response of the tool; generating voltage and current measurements from the galvanic tool using a calibration device; determining a leakage current value through at least one of the two electrodes based, at least in part, on the voltage and current measurements and the equation; and storing the leakage current value.

2 . The method of claim 1 further comprising:
receiving one or more voltage measurements from the galvanic tool captured while the galvanic tool is positioned in a borehole within a formation; and
calibrating the received voltage measurements using the stored leakage current value.

3 . The method of claim 2 further comprising:
determining at least one resistivity value for the formation using the calibrated voltage measurements.

4 . The method of claim 1 , wherein generating voltage and current measurements from the galvanic tool using the calibration device comprises
positioning the galvanic tool within a calibration box; injecting at least one current into the calibration box using at least one current electrode of the galvanic tool; and measuring a voltage response of the calibration box to the injected current using at least one voltage electrode of the galvanic tool.

5 . The method of claim 1 , wherein the equation comprises a linear equation modeling the response of the galvanic tool.

6 . The method of claim 1 , further comprising generating a calibration algorithm based, at least in part, on the stored leakage current value.

7 . The method of claim 1 , wherein determining the leakage current value comprises measuring the leakage current value.

8 . The method of claim 1 , further comprising
positioning the galvanic tool within a borehole in a formation; receiving at least one voltage measurement corresponding to the formation from the galvanic tool; receiving the stored leakage current value for the galvanic tool; and calibrating the at least one voltage measurement using stored leakage current value.

9 . A method, comprising:
positioning a galvanic tool within a borehole in a formation; receiving at least one of current and voltage measurements from the galvanic tool; receiving a stored leakage current value for the galvanic tool determined using at least one internal coupling impedance between at least two electrodes of the galvanic tool; and calibrating at least one of the received current and voltage measurements based, at least in part, on the stored leakage current value.

10 . The method of claim 9 , further comprising
receiving a downhole leakage current value from the galvanic tool positioned within the borehole; and calibrating at least one of the received current and voltage measurements based, at least in part, on the stored leakage current value and the downhole leakage current value.

11 . The method of claim 9 , further comprising determining at least one resistivity value for the formation using the calibrated voltage measurements.

12 . The method of claim 9 , further comprising
determining the at least one internal coupling impedance an internal coupling impedance between at least two electrodes of the galvanic tool; inputting the at least one internal coupling impedance into an equation used to evaluate the response of the tool; generating voltage and current measurements from the galvanic tool using a calibration device; and determining the stored leakage current value based, at least in part, on the voltage and current measurements and the equation.

13 . The method of claim 11 , wherein generating voltage and current measurements from the galvanic tool using the calibration device comprises
positioning the galvanic tool within a calibration box; injecting at least one current into the calibration box using at least one current electrode of the galvanic tool; and measuring a voltage response of the calibration box to the injected current using at least one voltage electrode of the galvanic tool.

14 . The method of claim 11 , wherein the equation comprises a linear equation modeling the response of the galvanic tool.

15 . The method of claim 11 , further comprising generating a calibration algorithm based, at least in part, on the stored leakage current value.

16 . A system, comprising:
a galvanic tool with at least two electrodes; an information handling system communicably coupled to the galvanic tool, the information handling system comprises a processor and memory device coupled to the processor, the memory device containing a set of instruction that, when executed by the processor, cause the processor to:
receive at least one of current and voltage measurements from the galvanic tool;
receive a leakage current value for the galvanic tool determined using at least one internal coupling impedance between at least two electrodes of the galvanic tool; and
calibrate at least one of the received current and voltage measurements based, at least in part, on the received leakage current value.

17 . The system of claim 16 , wherein the set of instructions further cause the processor to
receive a downhole leakage current value from the galvanic tool positioned within the borehole; and calibrate at least one of the received current and voltage measurements based, at least in part, on the stored leakage current value and the downhole leakage current value.

18 . The system of claim 16 , wherein the set of instructions further cause the processor to determine at least one resistivity value for the formation using the calibrated voltage measurements.

19 . The system of claim 16 , wherein the set of instructions that cause the processor to calibrate at least one of the received current and voltage measurements based, at least in part, on the received leakage current value further cause the processor to calibrate at least one of the received current and voltage measurements using a calibration algorithm determined using the received leakage current value.

Assignees

• Halliburton Energy Services Inc

Inventors

• San Martin Luis Emilio
• Donderici Burkay
• Fouda Ahmed E

Classifications

• G01V3/18

  specially adapted for well-logging · CPC title

• G01V13/00 Primary

  Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 · CPC title

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01V3/24 Primary

  using AC · CPC title