Apparatus and method for characterizing a reservoir

• US 20060000606A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Brockmeier, Oivind, Eghbali, Ali, Fensky, Charles, Harrigan, Edward, Fields, Troy, Hill, Bunker, Campo, Christopher Del
• Granted Patent: US 7,380,599 B2
• Time in Patent Office: Days
• US Class Current: 166/264
• CPC Class Codes: E21B 43/112 Perforators with extendable perforating members, e.g. actuated by fluid means
• CPC Class Codes: E21B 49/06 using side-wall drilling tools pressing or scrapers
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers

Abstract

An apparatus and method for characterizing a subsurface formation is provided. The apparatus includes a tool body, a probe assembly carried by the tool body for sealing off a region of the borehole wall, an actuator for moving the probe assembly between a retracted position for conveyance of the tool body and a deployed position for sealing off a region of the borehole wall and a perforator extending through the probe assembly for penetrating a portion of the sealed-off region of the borehole wall. The tool may be provided with first and second drilling shafts with bits for penetrating various surfaces. The method involves sealing off a region of a wall of an open borehole penetrating the formation, creating a perforation through a portion of the sealed-off region of the borehole wall and testing the formation.

Claims

1. An apparatus for characterizing a subsurface formation, comprising:

a tool body adapted for conveyance within a borehole penetrating the subsurface formation;

a probe assembly carried by the tool body for sealing off a region of the borehole wall;

an actuator for moving the probe assembly between a retracted position for conveyance of the tool body and a deployed position for sealing off a region of the borehole wall; and

a perforator extending through the probe assembly for penetrating a portion of the sealed-off region of the borehole wall.

2. The apparatus of claim 1, further comprising:

a flow line extending through a portion of the tool body and fluidly communicating with at least one of the perforator, the actuator, the probe assembly, and a combination thereof for admitting formation fluid into the tool body;

a pump carried within the tool body for drawing formation fluid into the tool body via the flow line.

3. The apparatus of claim 2, further comprising:

a sample chamber carried within the tool body for receiving formation fluid from the pump.

4. The apparatus of claim 2, further comprising:

an instrument carried within the tool body for analyzing formation fluid drawn into the tool body via the flow line and the pump.

5. The apparatus of claim 1, wherein the tool body is adapted for conveyance within a borehole via a wireline.

6. The apparatus of claim 1, wherein the tool body is adapted for conveyance within a borehole via a drillstring.

7. The apparatus of claim 1, wherein:

the probe assembly comprises a pair of inflatable packer rings each carried about axially-separated portions of the tool body and adapted for sealingly engaging axially-separated annular regions of the borehole wall.

8. The apparatus of claim 7, wherein:

the actuator comprises a hydraulic system for selectively inflating and deflating the packer rings.

9. The apparatus of claim 1, wherein:

the probe assembly is adapted for sealingly engaging a region of the borehole wall adjacent to one side of the tool body.

10. The apparatus of claim 9, further comprising:

an anchor system for supporting the tool body against a region of the borehole wall opposite the one side of the tool body.

11. The apparatus of claim 9, wherein the probe assembly comprises:

a substantially rigid plate; and

a compressible packer element mounted upon the plate.

12. The apparatus of claim 11, wherein the actuator comprises:

a plurality of pistons connected to the probe plate for moving the probe assembly between the retracted and deployed positions; and

a controllable energy source for powering the pistons.

13. The apparatus of claim 12, wherein:

the controllable energy source comprises a hydraulic system.

14. The apparatus of claim 1, wherein the perforator comprises:

at least one flexible drilling shaft having a drill bit connected to an end thereof for penetrating a portion of the sealed-off region of the borehole wall; and

a drilling motor assembly for applying torque and translatory force to the drilling shaft.

15. The apparatus of claim 14, wherein the perforator further comprises:

a tubular guide for directing the translatory path of the drilling shaft so as to effect a substantially normal penetration path by the drill bit through the borehole wall.

16. The apparatus of claim 15, wherein the tubular guide is flexible and is connected at one end to the drilling motor assembly and is connected at another end to the probe assembly.

17. The apparatus of claim 15, wherein the tubular guide is defined by a channel extending through a portion of the tool body.

18. The apparatus of claim 17, wherein the tubular guide includes a laterally-protuberant portion of the tool body through which a portion of the channel extends.

19. The apparatus of claim 17, wherein the tubular guide includes a substantially rigid tubular portion of the probe assembly that is concentric with a portion of the channel.

20. The apparatus of claim 1, wherein the perforator comprises at least one of an explosive charge, a hydraulic punch, a coring bit, and a combination thereof.

21. A method for characterizing a subsurface formation, comprising the steps of:

sealing off a region of a wall of an open borehole penetrating the formation;

creating a perforation through a portion of the sealed-off region of the borehole wall, the perforation extending beyond a damaged zone about the borehole; and

testing the formation.

22. The method of claim 21, further comprising the step of collecting a sample of formation fluid via the perforation.

23. The method of claim 22, further comprising the step of analyzing the collected sample of formation fluid.

24. An apparatus for perforating a cased borehole penetrating a subsurface formation, comprising:

a tool body adapted for conveyance within the cased borehole;

a first drilling shaft having a first drill bit connected to an end thereof for perforating a portion of the casing lining the borehole wall;

a second drilling shaft having a second drill bit connected to an end thereof for extending through the perforation in the casing and perforating a portion of the borehole wall;

a drilling motor assembly for applying torque and translatory force to the first and second drilling shafts; and

a coupling assembly for selectively coupling the drilling motor assembly to one of the first drilling shaft, the second drilling shaft, and combinations thereof.

25. The apparatus of claim 24, wherein the coupling assembly comprises:

a gear assembly operatively connected to both the first and second drilling shafts.

26. The apparatus of claim 25, wherein:

at least one of the drilling shafts is selectively operatively connected to the gear train.

27. The apparatus of claim 24, wherein:

the second drilling shaft has a defined drilling path; and

the coupling assembly comprises;

a bit coupling connected to an end of the first drilling shaft opposite the first drill bit; and

a means for selectively moving the first drilling shaft between a holding position and a drilling position, the drilling position being in the drilling path of the second drilling shaft enabling the second drill bit to engage the bit coupling and drive the first drilling shaft.

28. The apparatus of claim 27, wherein the moving means moves the first drilling shaft by a pivoting motion.

29. The apparatus of claim 27, wherein the moving means moves the first drilling shaft by a translatory motion.

30. The apparatus of claim 24, wherein:

the first and second drilling shafts have respective defined drilling paths; and

the coupling assembly comprises;

a bit coupling connected to an end of the first drilling shaft opposite the first drill bit; and

a means for selectively moving the second drilling shaft from its drilling path to the drilling path of the first drilling shaft enabling the second drill bit to engage the bit coupling and drive the first drilling shaft.

31. The apparatus of claim 24, further comprising an anchor system carried by the tool body for supporting the tool body within the borehole.

32. A method for perforating a cased borehole and penetrating a subsurface formation, comprising the steps of:

perforating a portion of the casing lining the borehole wall using a drilling motor assembly and a first drilling shaft having a first drill bit connected to an end thereof;

extending a second drilling shaft through the perforation in the casing using the drilling motor assembly, the second drilling shaft having a second drill bit connected to an end thereof for penetrating the formation; and

perforating a portion of the borehole wall using the drilling motor assembly and the second drilling shaft with the second drill bit;

the first and second drilling shafts being selectively coupled to the drilling motor assembly to execute the perforating and extending steps.