Fluid resistivity measurement tool

• US 8,464,796 B2
• Filed: 08/03/2010
• Issued: 06/18/2013
• Est. Priority Date: 08/03/2010
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Hoefel, Albert, Harms, Kent D., Stucker, Michael J.
• Primary Examiner(s): Neuder, William P
• Assistant Examiner(s): RUNYAN, RONALD R
• Application Number:
  US12/849,327
• Publication Number:
  US 20120031610A1
• Time in Patent Office: 1,050 Days
• Field of Search: 166/336, 166/250.1, 324/693, 324/366, 324/369, 731/521.8, 731/522.3, 731/522.4
• US Class Current: 166/336
• CPC Class Codes: E21B 49/08 Obtaining fluid samples or testing fluids, in boreholes or wells
• CPC Class Codes: E21B 49/0875 determining specific fluid parameters

Abstract

A downhole tool configured for conveyance within a borehole extending into a subterranean formation, wherein the downhole tool comprises a sensor assembly comprising a housing, a cap coupled to an end of the housing, a flow-line tube disposed within the housing and configured to receive fluid from the formation, a first winding disposed within the housing and configured to induce an electrical current in the fluid, and a second winding disposed within the housing and configured to detect the electrical current induced in the fluid by the first winding.

Claims

1. An apparatus, comprising:

a downhole tool configured for conveyance within a borehole extending into a subterranean formation, wherein the downhole tool comprises a sensor assembly comprising;

a housing;

a cap removably coupled to an end of the housing;

a flow-line tube disposed within the housing and configured to receive fluid from the formation or borehole;

a first winding disposed within the housing and configured to induce an electrical current in the fluid; and

a second winding disposed within the housing and configured to detect the electrical current induced in the fluid by the first winding;

a first chassis comprising a first flow-line extending therethrough; and

a second chassis coupled to the first chassis and comprising a second flow-line

extending therethrough, wherein the housing is disposed between the first and second chassis, and wherein the flow-line tube fluidly couples the first and second flow-lines.

2. The apparatus of claim 1 wherein the flow-line tube extends externally from the housing and the cap.

3. The apparatus of claim 1 wherein the sensor assembly further comprises a biasing member disposed between the housing and the first chassis.

4. The apparatus of claim 1 wherein the flow-line tube is electrically insulated.

5. The apparatus of claim 1 wherein the flow-line tube comprises a first portion having a first diameter and a second portion having a second diameter, wherein the second diameter is larger than the first diameter, and wherein the second portion is disposed between the first and second windings.

6. The apparatus of claim 5 wherein the second portion is removably coupled to the first portion.

7. The apparatus of claim 1 wherein the housing comprises a non-magnetic material.

8. The apparatus of claim 1 wherein the sensor assembly further comprises a detector thermally coupled to the flow-line tube and configured to detect a temperature of the flow-line tube.

9. The apparatus of claim 1 wherein the sensor assembly further comprises a detector electrically coupled to the flow-line tube and configured to detect an electrical leakage from the flow-line tube.

10. The apparatus of claim 1 wherein the sensor assembly further comprises a detector electrically coupled to the second winding and configured to detect a current of the second winding.

11. The apparatus of claim 1 wherein the sensor assembly further comprises a detector electrically coupled to the second winding and configured to detect a voltage of the second winding.

12. The apparatus of claim 1 wherein the downhole tool is configured for conveyance within the borehole via drill string.

13. The apparatus of claim 1 wherein the downhole tool is configured for conveyance within the borehole via wireline.

14. A method, comprising:

conveying a downhole tool within a borehole extending into a subterranean formation, wherein the downhole tool comprises a sensor assembly comprising;

a housing;

a cap removably coupled to an end of the housing;

a flow-line tube disposed within the housing;

a first winding disposed within the housing adjacent the flow-line tube; and

a second winding disposed within the housing adjacent the flow-line tube;

drawing fluid from the formation or borehole into the downhole tool and through the flow-line tube;

inducing an electrical current in the fluid within the flow-line tube;

detecting the electrical current induced in the fluid by the first winding; and

detecting an electrical leakage from the flow-line tube with a detector electrically coupled to the flow-line tube.

15. The method of claim 14 further comprising detecting a temperature of the flow-line tube with a detector thermally coupled to the flow-line tube.

16. The method of claim 14 further comprising detecting a current of the second winding with a detector electrically coupled to the second winding.

17. The method of claim 14 further comprising detecting a voltage of the second winding with a detector electrically coupled to the second winding.

18. The method of claim 14 wherein conveying the downhole tool within the borehole comprises conveyance via one of wireline and drill string.