Formation Evaluation While Drilling

• US 20080087470A1
• Filed: 11/20/2007
• Published: 04/17/2008
• Est. Priority Date: 12/19/2005
• Status: Abandoned Application

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: BOLZE, VICTOR, DUONG, KHANH, HARMS, KENT, STUCKER, MICHAEL, VILLAREAL, STEVEN, CIGLENEC, REINHART, POP, JULIAN
• Application Number:
  US11/942,796
• Publication Number:
  US 20080087470A1
• Time in Patent Office: Days
• US Class Current: 175/50
• CPC Class Codes: E21B 17/16 Drill collars
• CPC Class Codes: E21B 49/081 with down-hole means for trapping a fluid sample E21B49/10 takes precedence

Abstract

A sample module for a sampling while drilling tool includes a sample fluid flowline operatively connectable between a sample chamber and an inlet, for passing a downhole fluid. A primary piston divides the sample chamber into a sample volume and a buffer volume and includes a first face in fluid communication with the sample volume and a second face in fluid communication with the buffer volume. A secondary piston includes a first face in fluid communication with the buffer volume having buffer fluid disposed therein and a second face.

Claims

1. A sample module for a sampling while drilling tool positionable in a wellbore penetrating a subterranean formation, comprising:

a sample chamber having an inlet;

a sample fluid flowline operatively connectable to the sample chamber inlet for passing a downhole fluid thereto;

a primary piston slidably disposed within the sample chamber and dividing the sample chamber into a sample volume and a buffer volume, the primary piston having a first face in fluid communication with the sample volume and a second face in fluid communication with the buffer volume;

a secondary piston having a first face in fluid communication with the buffer volume and a second face; and

a buffer fluid disposed in the buffer volume.

2. The sample module of claim 1, in which the secondary piston is slidably disposed in the sample chamber.

3. The sample module of claim 1, further comprising a buffer chamber in fluid communication with the buffer volume, and in which the secondary piston is disposed in the buffer chamber.

4. The sample module of claim 3, further comprising a second sample chamber in fluid communication with the buffer chamber.

5. The sample module of claim 3, in which the secondary piston comprises a stepped piston.

6. The sample module of claim 3, further comprising a dump chamber in fluid communication with the secondary piston first face and a fluid at substantially atmospheric pressure disposed within the dump chamber.

7. The sample module of claim 1, in which the buffer fluid comprises a liquid.

8. The sample module of claim 7, in which the secondary piston second face fluidly communicates with a fluid at substantially atmospheric pressure.

9. The sample module of claim 1, in which the buffer fluid comprises a gas.

10. The sample module of claim 1, further comprising a mud flowline fluidly communicating wellbore mud to the secondary piston second face.

11. The sample module of claim 10, further comprising a mud passage through which wellbore mud passes, and in which the mud flowline fluidly communicates with the mud passage.

12. The sample module of claim 10, further comprising a mud orifice in fluid communication with the wellbore, and in which the mud flowline fluidly communicates with the mud orifice.

13. The sample module of claim 1, in which the sample chamber is inverted so that the sample chamber inlet is below the primary piston.

14. The sample module of claim 1, further comprising a sensor operatively communicating with the sample volume.

15. The sample module of claim 1, further comprising an agitator disposed in the sample volume for agitating the sample fluid.

16. A sample module for a sampling while drilling tool positionable in a wellbore penetrating a subterranean formation, comprising:

a sample chamber having an inlet and a sealed end opposite the inlet;

a sample fluid flowline operatively connectable to the sample chamber inlet for passing a downhole fluid thereto;

a primary piston slidably disposed within the sample chamber and dividing the sample chamber into a sample volume and a buffer volume, the primary piston having a first face in fluid communication with the sample volume and a second face in fluid communication with the buffer volume; and

a buffer fluid at substantially atmospheric pressure disposed in the buffer volume, wherein the sample chamber is detachably coupled to the sample module.

17. The sample module of claim 16, further comprising a sensor operatively communicating with the sample volume.

18. A method of obtaining a fluid sample with a sampling while drilling tool, comprising:

lowering a tool in a wellbore penetrating a subterranean formation, the tool including a sample chamber having a first volume and a second volume;

flowing a sample fluid through an inlet of the tool into the first volume of the sample chamber;

moving a first piston disposed between the first and second volumes, thereby increasing the first volume;

moving a buffer fluid from a first position to a second position with at least one of the first and a second piston; and

moving the second piston disposed between the second and a third volume, thereby decreasing the third volume.

19. The method of claim 18, wherein the third volume is disposed in the sample chamber.

20. The method of claim 18, wherein the third volume is fluidly connected to one of a mud passage and a mud orifice.

21. The method of claim 18, including removing the sample chamber from the tool with the sample fluid disposed therein.

22. The method of claim 18, including agitating the sample fluid in the sample volume with an agitator.

23. The method of claim 18, including restricting the flow of the buffer fluid.

24. The method of claim 23, wherein restricting the flow includes regulating a flow of the buffer fluid within the second volume.

25. The method of claim 18, including measuring a property of the sample fluid in the sample chamber.