Method and apparatus for MWD formation testing

• US 20040011525A1
• Filed: 05/19/2003
• Published: 01/22/2004
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Jones, Dale Allen, Franzen, Andrew T., Menconi, John R.
• Granted Patent: US 7,080,552 B2
• Time in Patent Office: Days
• US Class Current: 166/264
• CPC Class Codes: E21B 17/1014 Flexible or expansible centering means, e.g. with pistons pressing against the wall of the well E21B17/1042 takes precedence
• CPC Class Codes: E21B 49/008 by injection test; by analysing pressure variations in an injection or production test, e.g. for estimating the skin factor measuring pressure E21B47/06
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers
• CPC Class Codes: Y02E 30/10 Nuclear fusion reactors

Abstract

A method and apparatus for formation testing is disclosed. In a preferred embodiment, a formation testing tool includes a longitudinal body with a flowbore; a plurality of extendable centralizing pistons coupled to the body; an extendable sample device coupled to the body; and a centralizing hydraulic circuit configured to cause each of the plurality of centralizing pistons to extend at substantially the same rate. The centralizing hydraulic circuit includes a series of flow control and pressure-determining valves configured to extend the centralizing pistons at substantially the same rate, and to help maintain stability in the hydraulic circuit in response to external pressures. In some embodiments, the extendable sample device is preferably configured to be recessed beneath a surface of the body in a first position and to extend beyond the surface in a second position. The extendable sample device is preferably extended to contact the borehole wall substantially normal to the wall, protecting the sample device from excessive bending moments and other excessive forces.

Claims

1. A formation testing tool comprising:

a longitudinal body having a flowbore;

a plurality of extendable centralizing pistons coupled to the body;

an extendable sample device coupled to the body; and

a centralizing hydraulic circuit configured to cause each of the plurality of centralizing pistons to extend at substantially the same rate.

2. The formation testing tool of claim 1 further comprising a plurality of extendable sample devices coupled to the body.

3. The formation testing tool of claim 1 wherein all of the plurality of extendable centralizing pistons are located at the same cross-section of the body.

4. The formation testing tool of claim 1 wherein at least one of the plurality of extendable centralizing pistons is located at a different cross-section than the remaining extendable centralizing piston or pistons.

5. The formation testing tool of claim 1 further comprising:

a sample device hydraulic circuit configured to cause the sample device to extend; and

a controller for controlling the centralizing hydraulic circuit and the sample device hydraulic circuit.

6. The formation testing tool of claim 5 further comprising a pressure transducer coupled with the controller, the centralizing hydraulic circuit, and the sample device hydraulic circuit.

7. A formation testing tool comprising:

a longitudinal body having a surface;

an extendable sample device coupled to the body, the extendable sample device configured to be recessed beneath the surface of the body in a first position and to extend beyond the surface in a second position.

8. A formation testing tool comprising:

a longitudinal body;

an extendable sample device coupled to the body; and

a plurality of extendable centralizing pistons coupled to the body, the extendable centralizing pistons being configured to extend at substantially the same rate.

9. The formation testing tool of claim 8 wherein the plurality of extendable centralizing pistons are received in cylinders in the body, each cylinder having an extend side and a retract side of its corresponding cylinder, the formation testing tool further comprising:

a source of hydraulic fluid;

a plurality of flow control valves, each flow control valve configured to communicate hydraulic fluid from the source to the extend side of a corresponding cylinder, each flow control valve communicating hydraulic fluid at substantially the same rate.

10. The formation testing tool of claim 9 further comprising:

a first pressure-determining valve in fluid communication with the retract side of the cylinders, the valve preventing the centralizing pistons from moving until the pressure on the retract side of the cylinders reaches a predetermined pressure.

11. The formation testing tool of claim 10 wherein the first pressure-determining valve is a relief valve configured to actuate at the predetermined pressure, the actuation of the relief valve allowing hydraulic fluid to flow from the retract side of the cylinders.

12. The formation testing tool of claim 10 wherein the first pressure-determining valve comprises a solenoid activated valve.

13. The formation testing tool of claim 10 further comprising:

a second pressure-determining valve coupled between the hydraulic fluid source and the plurality of flow control valves, the second pressure-determining valve configured to communicate hydraulic fluid from the source to add the pressure to extend the plurality of centralizing pistons.

14. The formation testing tool of claim 13 wherein the second pressure-determining valve comprises a solenoid activated valve.

15. The formation testing tool of claim 10 further comprising a pilot control valve coupled between one of the plurality of flow control valves and the extend side of its corresponding cylinder, the pilot control valve configured to prevent the flow of hydraulic fluid out of the extend side of the cylinder unless the pressure on the retract side of the cylinder exceeds the predetermined pressure.

16. The formation testing tool of claim 10 further comprising a fail-safe valve coupled to the extend side of the cylinders, the fail-safe valve configured to remove the pressure to extend the plurality of centralizing pistons when power is removed from the fail-safe valve.

17. The formation testing tool of claim 16 wherein the fail-safe valve comprises a powered valve which in its unpowered condition communicates hydraulic fluid from the extend side of the cylinders to a hydraulic reservoir.

18. The formation testing tool of claim 17 wherein the powered valve comprises a solenoid activated valve.

19. The formation testing tool of claim 9 wherein each flow control valve has an inlet side and an outlet side and allows fluid to flow from the inlet side to the outlet side when the pressure on the outlet side is between a lower limit pressure and an upper limit pressure.

20. The formation testing tool of claim 19 wherein the lower limit pressure is 200 p.s.i. and the upper limit pressure is 3,000 p.s.i.

21. The formation testing tool of claim 8 wherein the extendable sample device is received in a sample device cylinder in the body, the sample device cylinder having an extend side and a retract side of its corresponding cylinder, the formation testing tool further comprising:

a source of hydraulic fluid;

a sample device extend valve, the sample device extend valve configured to communicate hydraulic fluid from the source to the extend side of the sample device cylinder; and

a draw down chamber communicating with the hydraulic fluid source, the draw down chamber configured to actuate when the extend side of the sample device cylinder reaches a predetermined pressure.

22. The formation testing tool of claim 21 wherein the draw down chamber is received in a draw down cylinder in the body, the draw down chamber cylinder having an extend side and a retract side of its corresponding cylinder, the formation testing tool further comprising:

a sample device retract valve, the sample device retract valve configured to communicate hydraulic fluid from the source to the retract side of the sample device cylinder;

a draw down chamber extend valve, the draw down chamber extend valve configured to communicate hydraulic fluid from the source to the extend side of the draw down cylinder;

a draw down chamber retract valve, the draw down chamber retract valve configured to communicate hydraulic fluid from the source to the retract side of the draw down cylinder;

a hydraulic fluid pressure transducer; and

a formation fluid pressure transducer coupled between the draw down chamber and the extendable sample device.

23. A method for formation testing comprising:

extending at substantially the same rate a plurality of centering pistons from a formation testing tool;

centering the formation testing tool in a borehole; and

testing the formation.

24. The method of claim 23 wherein the testing step comprises extending a testing piston, separate from the plurality of centering pistons.

25. The method of claim 23 wherein extending a plurality of centering pistons comprises:

receiving a command from a controller;

starting a motor in response to receiving the command;

opening a centering piston extend valve; and

communicating from a hydraulic fluid source hydraulic fluid to each of the plurality of centering pistons to cause each of the centering pistons to extend at substantially the same rate.

26. The method of claim 24 wherein extending a testing piston comprises:

opening a testing piston extend valve;

communicating from a hydraulic fluid source hydraulic fluid to the testing piston;

exerting a hydraulic fluid pressure on the testing piston; and

stabilizing the fluid pressure.

27. The method of claim 26 wherein testing further comprises:

opening a draw down chamber retract valve;

communicating hydraulic fluid from the hydraulic source to the draw down chamber;

exerting a hydraulic fluid pressure on the draw down chamber;

communicating a formation fluid sample from the testing piston to the draw down chamber; and

comparing the formation fluid sample pressure to an annulus fluid pressure.

28. The method of claim 27 wherein testing further includes ejecting the formation fluid sample from the drawdown chamber and from the testing piston if the formation fluid sample pressure and the annulus fluid pressure are substantially the same.

29. The method of claim 27 wherein testing further includes performing a fluid test on the formation fluid sample.