Well ranging apparatus, systems, and methods

Patent metadata

Field	Value
Publication number	US-10273799-B2
Application number	US-201514769525-A
Country	US
Kind code	B2
Filing date	Aug 4, 2015
Priority date	Aug 11, 2014
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Embodiments include well ranging apparatus, systems, and methods which operate to measure a total magnetic field strength at each of three sensors attached to a down hole tool housing, wherein each sensor is to provide normal, tangential, and longitudinal field strength component amplitude values, and wherein at least one of the sensors is attached to the housing spaced approximately equidistant from the other two sensors in an azimuthal plane of the housing, and wherein each of the sensors is spaced apart from the other sensors in a longitudinal direction of the housing. Further activity includes determining at least three gradient field values from the total magnetic field strength measured by the three sensors, and determining an approximate range from a first well in which the sensors are disposed, to a casing of a second well, using the at least three gradient field values. Additional apparatus, systems, and methods are disclosed.

First claim

What is claimed is:

1. An apparatus, comprising:
a down hole tool housing attached to three electromagnetic field strength sensors, each of the sensors to measure electromagnetic field strength components along three different axes comprising a normal component N, a tangential component T, and a vertical component z, wherein the three electromagnetic field strength sensors are spaced around the downhole tool housing in a longitudinal direction and wherein each electromagnetic field strength sensor occupies a respective azimuthal plane, and
a non-transitory machine readable medium having program code executable by a processor to cause the processor to determine a gradient field value along a direction of a line through a given one of the electromagnetic field strength sensors.

2. The apparatus of claim 1 , wherein at least one of the sensors is spaced apart from the other two sensors in the longitudinal direction of the housing.

3. The apparatus of claim 1 , wherein each one of the sensors is spaced apart from the other two sensors in the longitudinal direction of the housing.

4. The apparatus of claim 1 , wherein each of the sensors is spaced approximately equidistant from the other two sensors.

5. The apparatus of claim 1 , further comprising:
a fourth electromagnetic field strength sensor.

6. The apparatus of claim 5 , wherein the fourth electromagnetic field strength sensor is spaced approximately equidistant from two of the three electromagnetic field strength sensors.

7. The apparatus of claim 1 , further comprising:
a range determination module to receive signals representing magnetic field strength values from the sensors, and to determine an approximate range from the sensors disposed in a first well, to a second well, via direct transmission or backscatter transmission of electromagnetic waves.

8. The apparatus of claim 7 , wherein the first well comprises a drilling well, and wherein the second well comprises a target well.

9. The apparatus of claim 1 , wherein the three different axes are with respect to a bottom hole assembly.

10. The apparatus of claim 1 , wherein the gradient field value indicates how electromagnetic field strength components change as a function of position along the line; and wherein the gradient field value is based on the measured electromagnetic field strength components at the given one of the electromagnetic field strength sensors.

11. The apparatus of claim 1 , wherein a pair of the electromagnetic field strength sensors as physical sensors is used to create a pseudo sensor between the pair; and wherein the direction of the line passes through the pseudo sensor and the given one of the electromagnetic field strength sensors.

12. The method of claim 1 , wherein the three electromagnetic field strength sensors spaced around the downhole tool housing comprises the three electromagnetic field strength sensors spaced around and outside the downhole tool housing.

13. A system, comprising:
a source of current or voltage to electrically couple to a well casing of a well or to attach to a down hole tool housing; and
an apparatus comprising a range determination module to receive electromagnetic field strength measurements from three electromagnetic field strength sensors attached to the down hole tool housing, each of the sensors to measure electromagnetic field strength components along three different axes comprising a normal component N, a tangential component T, and a vertical component z, wherein at least one of the sensors is spaced approximately equidistant from the other two sensors in an azimuthal plane of the housing, and wherein at least one of the sensors is spaced apart from another one of the sensors in a longitudinal direction of the housing and to determine a gradient field value along a direction of a line through a given one of the electromagnetic field strength sensors.

14. The system of claim 13 , wherein the source comprises a source of current to couple current to the well casing of the well comprising a target well.

15. The system of claim 14 , wherein the apparatus comprises a drill string.

16. The system of claim 13 , wherein the down hole tool housing comprises one or more of a wireline sonde, a bottom hole assembly, a drill collar, a drill string pipe, or a sub.

17. The system of claim 13 , wherein the three different axes are with respect to a bottom hole assembly.

18. The system of claim 13 , wherein the gradient field value indicates how electromagnetic field strength changes as a function of position along the line, and wherein the gradient field value is based on the measured electromagnetic field strength at the given one of the electromagnetic field strength sensors.

19. The system of claim 13 , wherein a pair of the electromagnetic field strength sensors as physical sensors is used to create a pseudo sensor between the pair; and wherein the direction of the line passes through the pseudo sensor and the given one of the electromagnetic field strength sensors.

20. A method, comprising:
positioning a down hole tool housing in a borehole of a subsurface formation;
injecting a current into a conductor arranged in the subsurface formation;
measuring a total magnetic field strength at each of three sensors attached to hall the down hole tool housing, wherein each sensor is to provide normal, tangential, and longitudinal field strength component amplitude values, and wherein at least one of the sensors is attached to the housing spaced approximately equidistant from the other two sensors in an azimuthal plane of the housing, and wherein at least one of the sensors is spaced apart from another one of the sensors in a longitudinal direction of the housing;
determining at least three gradient field values from the total magnetic field strength measured by the three sensors, wherein a given gradient field value is along a direction of a line through a given one of the sensors; and
determining an approximate range from a first well in which the sensors are disposed, to a casing of a second well, using the at least three gradient field values.

21. The method of claim 20 , wherein determining the approximate range from the first well comprises:
determining the approximate range from a drilling well in which the sensors are disposed, to the casing of the second well comprising a target well casing.

22. The method of claim 20 , wherein each one of the sensors is spaced apart from another one of the sensors in the longitudinal direction of the housing.

23. The method of claim 20 , wherein each one of the sensors is spaced approximately equidistant from the other two sensors in the azimuthal plane of the housing.

24. The method of claim 20 , wherein a finite difference method is used to calculate the total magnetic field strength and total magnetic gradient field from two of the sensors, along the line, the line including the two of the sensors.

25. The method of claim 20 , wherein a ranging sensitivity direction is determined for each of three pairs of sensors, comprising three paired combinations of the three sensors.

26. The method of claim 20 , wherein a pair of the sensors as physical sensors is used to create a pseudo sensor between the pair, and wherein the total magnetic field strength S12 for the pseudo sensor is determined according to the formula:

Assignees

• Halliburton Energy Services Inc

Inventors

• Roberson Brian
• Wu Hsu-Hsiang
• Beste Randal Thomas

Classifications

• G01V3/26 Primary

  operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) · CPC title

• E21B47/0228 Primary

  using electromagnetic energy or detectors therefor · CPC title

• E21B43/2406

  Steam assisted gravity drainage [SAGD] · CPC title

• E21B7/04

  Directional drilling · CPC title

• E21B47/024

  of devices in the borehole (determining slope or direction of the borehole E21B47/022) · CPC title