Fiber Optic Current Monitoring for Electromagnetic Ranging

Patent metadata

Field	Value
Publication number	US-2016237807-A1
Application number	US-201315031207-A
Country	US
Kind code	A1
Filing date	Dec 18, 2013
Priority date	Dec 18, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

A wellbore ranging system and method utilized between first and second wellbores includes an electromagnetic field sensing instrument disposed in the second wellbore, a conductive casing in the first wellbore, an electric current source exciting current flow in the conductive member, and a fiber optic sensor disposed adjacent the conductive member. The current flow along the conductive member results in a magnetic field which is measured by the sensing instrument. The fiber optic sensor includes a core that is responsive to the magnetic field in which it is disposed. The responsive core alters the optical property of an optical wave guide forming the sensor, which altered optical property can be utilized to measure the magnitude of the electrical current at the position of the sensor. The magnitude of the current and the measured magnetic field can be utilized to determine a range between the first and second wellbores.

First claim

1 . A wellbore ranging system for surveying a target wellbore from a second wellbore, said system comprising:
an electromagnetic field sensing instrument disposed in the second wellbore; an elongated conductive member disposed in the target wellbore, the conductive member oriented along an axis that is substantially parallel with the target wellbore; an electric current source exciting current flow in the conductive member of the target wellbore; and a fiber optic sensor disposed adjacent the conductive member of the target wellbore.

2 . The system of claim 1 wherein said fiber optic sensor comprises an optical fiber and a core formed of material selected from the group consisting of magnetically responsive material and electrically responsive material; wherein the optical fiber is disposed adjacent said core.

3 . The sensor of claim 2 , wherein the core is formed of a magnetostrictive material and the optical fiber is bonded to the core.

4 . The sensor of claim 2 , wherein the core is formed of a magnetically permeable material and the optical fiber forms at least one loop around the core.

5 . The sensor of claim 2 , wherein the core is formed of an electrostrictive material and the optical fiber is bonded to the core.

6 . The sensor of claim 2 wherein said core is comprised of an elongated body disposed along an axis and the sensor is positioned adjacent the conductive member so that the elongated axis of the core is substantially perpendicular to the axis of the conductive member.

7 . The sensor of claim 1 , further comprising a fiber optic interrogation system in optical communication with the fiber optic sensor.

8 . The system of claim 7 , further comprising an optical fiber extending from the fiber optic interrogation system to the fiber optic sensor.

9 . The system of claim 1 , further comprising a plurality of optic sensors disposed along at least a portion of the length of the conductive member to form a sensor array.

10 . The system of claim 1 , wherein the conductive member is casing.

11 . The system of claim 1 , wherein the conductive member is a tubular positioned within the target wellbore.

12 . The system of claim 1 , wherein the electric current source is in direct electrical communication with the conductive member.

13 . The system of claim 1 , further comprising a drill string in the second wellbore, the drill string having multiple drill pipe sections with a drill bit disposed on an end of the drill string, wherein the electromagnetic sensor is carried by the drill string.

14 . A wellbore ranging system for surveying a target wellbore from a second wellbore, said system comprising:
a bottom hole assembly carried at the distal end of a drill string disposed in the second wellbore, the bottom hole assembly comprising an electromagnetic field sensing instrument and a drill bit; an elongated conductive member disposed in the target wellbore, the conductive member oriented along an axis that is substantially parallel with the target wellbore; an electric current source exciting current flow in the conductive member of the target wellbore; and a fiber optic sensor system, the fiber optic sensor system comprising:
a plurality of spaced apart fiber optic sensors, each sensor having a core formed of material selected from the group consisting of magnetically responsive material and electrically responsive material;
a fiber optic interrogation system; and
an optical fiber extending from the fiber optic interrogation system to the cores, wherein a portion of the optical fiber is disposed adjacent to each core.

15 . The system of claim 14 , wherein the conductive member is an electrically conductive casing disposed within the target wellbore and wherein the electric current source is in direct electrical communication with the conductive member, the bottom hole assembly further comprising a power system disposed to provide power to the electromagnetic field sensing instrument and a directional steering system disposed to steer the drill bit.

16 . A method for electromagnetic ranging comprising:
positioning an optical fiber in a target wellbore having a conductive member disposed therein; applying a current flow to the conductive member; and utilizing the optical fiber to measure the current flow on the conductive member.

17 . The method of claim 16 , wherein the magnitude of the current flow at at least one location along the conductive member is measured.

18 . The method of claim 16 , wherein the intensity of the current flow along the conductive member is measured.

19 . The method of claim 16 , further comprising positioning a magnetically responsive material adjacent the optical fiber.

20 . The method of claim 19 , further comprising altering an optical response of the optical fiber utilizing the magnetically responsive material.

21 . The method of claim 20 , further comprising altering a property of the magnetically responsive material by positioning the magnetically responsive material in a magnetic field produced by the current flow in the conductive member.

22 . The method of claim 16 , further comprising:
utilizing an electromagnetic field sensing instrument disposed in a second wellbore to measure a magnetic field emanating from the conductive member; and determining a range of the target wellbore from the second wellbore utilizing the measured magnetic field and measured current flow.

23 . The method of claim 22 , further comprising utilizing the range to guide a drill bit.

24 . The method of claim 16 , further comprising:
drilling the wellbore being drilled; suspending drilling and measuring the electromagnetic field; and continuing drilling based on the measured electromagnetic field and current.

25 . The method of claim 16 , further comprising:
providing an optical sensor having an optical fiber disposed adjacent a sensor core formed of material selected from the group consisting of magnetically responsive material and electrically responsive material; and utilizing the core to alter the optical response of the optical fiber.

26 . The method of claim 25 , further comprising, measuring a property based on the altered optical response.

27 . The method of claim 25 , further comprising, inducing a strain on the optical fiber based on the altered core.

28 . The method of claim 25 , further comprising utilizing a magnetic field to alter the optical response of the optical fiber.

29 . The method of claim 22 , further comprising:
injecting steam in one of the wellbores to cause hydrocarbons in the formation to migrate to the other wellbore; and recovering hydrocarbons from the other wellbore.

Assignees

• Halliburton Energy Services Inc

Inventors

• Wilson Glenn A
• Donderici Burkay

Classifications

• E21B47/135

  using light waves, e.g. infrared or ultraviolet waves · CPC title

• G01V3/02

  operating with propagation of electric current · CPC title

• E21B44/005

  Below-ground automatic control systems · CPC title

• E21B47/024

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

• E21B7/04 Primary

  Directional drilling · CPC title