Claims
- 1. A downhole formation test tool, comprising;
a. a carrier member for conveying the formation test toot into a borehole; b. a retractably extendable pad for sealingly engaging a borehole wall adjacent a fluid bearing formation, the pad having a port therein for receiving fluid from said formation; c. a fluid transfer device operatively associated with the retactably extendable pad for selectively adjusting a fluid pressure; d. a sensor for detecting the fluid pressure proximate said port; and e. a downhole controller operatively coupled to the sensor and the fluid transfer device, said downhole controller acting according to programmed instructions to control said fluid transfer device in response to signals from said sensor thereby adjusting the fluid pressure at the port as the retractably extendable pad is extended and reacted.
- 2. The tool of claim 1 wherein the carrier member is selected from a group consisting of (i) a jointed pipe drill string; (ii) a coiled tube; and (iii) wireline.
- 3. The toot of claim 1 wherein the retractably extendable pad is an elastomeric cushion.
- 4. The tool of claim 1 wherein the fluid transfer device includes at least one piston cooperatively associated with the retractably extendable pad.
- 5. The tool of claim 4, wherein the at least one piston is operated by an electric motor.
- 6. The tool of claim 5 wherein the electric motor is selected from a group consisting of (i) a spindle motor and (ii) a stepper motor.
- 7. The tool of claim 5 wherein the electric motor further comprises a ball screw assembly for translating the at least one piston.
- 8. A method for engaging and disengaging a retactably extendable pad with a fluid bearing formation during a formation test, comprising:
a. conveying a tool on a carrier member into a borehole proximate the fluid bearing formation; b. extending the pad from the tool to sealingly engage a borehole wall, said pad having a port therein for receiving fluid from said fluid bearing formation, said port being in fluid communication with said sample volume; c. detecting the sample volume fluid pressure proximate said port; and d. adjusting said sample volume in response to said detected fluid pressure to provide a fist predetermined sample volume pressure during engagement of said pad with said borehole wall and a second predetermined pressure during disengagement of said pad with said borehole wall.
- 9. The method of claim 8 wherein the carrier member is selected from a group consisting of (i) a drill pipe; (ii) a coiled tubing, and (iii) a wireline.
- 10. The method of claim 8 wherein the first predetermined pressure is a substantially constant sample volume pressure during engagement.
- 11. The method of claim 8, wherein the second predetermined pressure is greater than a formation pressure by a predetermined value.
- 12. A method for reducing build-up time during a formation test, comprising;
a. conveying a tool on a carrier member into a borehole proximate the fluid bearing formation; b. extending the pad from the tool to sealingly engage a borehole wall, said pad having a port therein for receiving fluid from said fluid bearing formation, said port being in fluid communication with said sample volume; c. continuously detecting the sample volume fluid pressure proximate said port; d. moving a sample piston a first predetermined distance in a first direction thereby urging formation fluid to enter said sample volume; e. analyzing the build-up pressure response to estimate the build-np time; and f. moving said sample piston a second predetermined distance in a reverse second direction to shorten said build-up time.
- 13. The method of claim 12 wherein the carrier member is selected from a group consisting of (i) a drill pipe; (H) a coiled tubing; and (iii) a wireline.
- 14. A method for determining a constant draw down rate at a predetermined pressure below a formation pressure, comprising:
a conveying a tool on a carrier member into a borehole proximate the fluid bearing formation; b. extending the pad from the tool to sealingly engage a borehole wall, said pad having a port therein for receiving fluid from said fluid bearing formation, said port being in fluid communication with said sample volume; c. continuously detecting the sample volume fluid pressure proximate said port; d. moving a sample piston at a predetermined initial draw rate thereby urging formation fluid to enter said sample volume; e. determining a pressure-time slope of said sample volume fluid pressure; and f. iteratively adjusting said draw rate until said pressure-time slope is substantially zero at said predetermined pressure.
- 15. The method of claim 12 wherein the carrier member is selected from a group consisting of (i) a drill pipe; (ii) a coiled tubing; and (ii) a wireline.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation-in-Part of U.S. patent application Ser. No. 09/621,398 filed on Jul. 21, 2000, and is related to U.S. patent application Ser. No. 10/213,865 filed on Aug. 7, 2002, that is a Continuation of U.S. patent application Ser. No. 09/621,398.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09621398 |
Jul 2000 |
US |
Child |
10247434 |
Jul 2003 |
US |