Ranging and resistivity evaluation using current signals

Patent metadata

Field	Value
Publication number	US-2018239043-A1
Application number	US-201615754549-A
Country	US
Kind code	A1
Filing date	May 6, 2016
Priority date	May 6, 2016
Publication date	Aug 23, 2018
Grant date	—

Abstract

Methods, systems, and computer program products use current leakage rates to evaluate the resistivity of a subterranean formation around a drilling well in conjunction with a ranging operation. The evaluation entails obtaining a current distribution along a section of the drilling well as part of a ranging measurement. The current distribution allows the current leakage rate to be determined along that section of the drilling well. Multiple current leakage rates may then be determined along the drilling well to produce a leakage rate curve that may be matched with modeled or known leakage rate curves to estimate the formation resistivity around the drilling well. Formation resistivity may also be calculated from the current distribution using an appropriate equation. The ability to obtain a current distribution along a section of the drilling well as part of a ranging measurement allows formation resistivity to be evaluated in conjunction with ranging operations.

First claim

1 . A ranging and resistivity evaluation system, comprising:
a power source coupled to provide a current signal on a conductive material in a wellbore as part of a ranging operation; at least one sensor disposed on the conductive material in the wellbore and configured to detect the current signal; a formation evaluation system coupled to receive sensor data representing the current signal from the at least one sensor; and a formation resistivity evaluation tool residing in the formation evaluation system, the formation resistivity evaluation tool operable to obtain a current distribution along the conductive material from the sensor data and calculate a resistivity of the formation from the current distribution.

2 . The system of claim 1 , wherein the formation resistivity evaluation tool is further operable to determine a current leakage rate from the current distribution.

3 . The system of claim 2 , wherein the formation resistivity evaluation tool is further operable to estimate the resistivity of the formation from the current leakage rate.

4 . The system of claim 3 , wherein the formation resistivity evaluation tool is further operable to provide at least one modeled current leakage rate corresponding to at least one known formation resistivity for comparison to the estimated resistivity.

5 . The system of claim 4 , wherein the formation resistivity evaluation tool is further operable to calibrate the at least one modeled current leakage rate using the estimated resistivity.

6 . The system of claim 1 , wherein the at least one sensor is one of: a magnetometer, a toroid transformer, or a voltage sensor.

7 . The system of claim 1 , wherein the conductive material is one of: a component of a bottom hole assembly in the wellbore, or a segment of a drill string in the wellbore.

8 . The system of claim 1 , wherein the component of the bottom hole assembly is a drill collar.

9 . The system of claim 1 , wherein the at least one sensor comprises multiple sensors arranged according to one of: azimuthally around the conductive material, or lengthwise along the conductive material.

10 . A method of evaluating a resistivity of a formation in conjunction with a ranging operation, comprising:
providing a current signal on a conductive material in a wellbore as part of the ranging operation; detecting the current signal by at least one sensor disposed on the conductive material in the wellbore; receiving sensor data representing the current signal from the at least one sensor; obtaining a current distribution along the conductive material from the sensor data; and calculating a resistivity of the formation from the current distribution.

11 . The method of claim 10 , further comprising determining a current leakage rate from the current distribution.

12 . The method of claim 11 , further comprising estimating the resistivity of the formation from the current leakage rate.

13 . The method of claim 12 , further comprising providing at least one modeled current leakage rate corresponding to at least one known formation resistivity for comparison to the estimated resistivity.

14 . The method of claim 13 , further comprising calibrating the at least one modeled current leakage rate using the estimated resistivity.

15 . The method of claim 10 , wherein the at least one sensor is one of: a magnetometer, a toroid transformer, or a voltage sensor.

16 . The method of claim 10 , wherein the conductive material is one of: a component of a bottom hole assembly in the wellbore, or a segment of a drill string in the wellbore.

17 . The method of claim 10 , wherein the component of the bottom hole assembly is a drill collar.

18 . The method of claim 10 , wherein the at least one sensor comprises multiple sensors arranged according to one of: azimuthally around the conductive material, or lengthwise along the conductive material.

19 . A non-transitory computer-readable medium storing computer-readable instructions for evaluating a resistivity of a formation surrounding a wellbore, the computer-readable instructions causing a computing system to:
detect a current signal by at least one sensor disposed on a conductive material in the wellbore, the current signal being provided on the conductive material in the wellbore as part of a ranging operation; receive sensor data representing the current signal from the at least one sensor; obtain a current distribution along the conductive material from the sensor data; and calculate a resistivity of the formation from the current distribution.

20 . The computer-readable medium of claim 19 , further comprising computer-readable instructions for causing the computing system to determine a current leakage rate from the current distribution.

21 . The computer-readable medium of claim 20 , further comprising computer-readable instructions for causing the computing system to calculate the resistivity of the formation from the current leakage rate.

22 . The computer-readable medium of claim 21 , further comprising computer-readable instructions for causing the computing system to provide at least one modeled current leakage rate corresponding to at least one known formation resistivity for comparison to the estimated resistivity.

23 . The computer-readable medium of claim 22 , wherein the formation resistivity evaluation tool is further operable to calibrate the at least one modeled current leakage rate using the estimated resistivity.

24 . The computer-readable medium of claim 19 , wherein the at least one sensor is one of: a magnetometer, a toroid transformer, or a voltage sensor.

25 . The computer-readable medium of claim 19 , further comprising a bottom hole assembly in the wellbore, wherein the conductive material is one of: a component of a bottom hole assembly in the wellbore, or a segment of a drill string in the wellbore.

26 . The computer-readable medium of claim 19 , wherein the component of the bottom hole assembly is a drill collar.

27 . The computer-readable medium of claim 19 , wherein the at least one sensor comprises multiple sensors arranged according to one of: azimuthally around the conductive material, or lengthwise along the conductive material.

Assignees

• Halliburton Energy Services Inc

Inventors

• Wu Hsu-Hsiang
• Donderici Burkay

Classifications

• G01V3/12

  operating with electromagnetic waves {(operating with millimetre waves G01V8/005)} · CPC title

• G01V3/08 Primary

  operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) · CPC title

• G01V3/22 Primary

  using DC · CPC title

• G01V3/24

  using AC · CPC title

• G01V11/002

  Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant (means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B) · CPC title