Borehole imaging system for conductive and resistive drilling fluids

• US 8,022,983 B2
• Filed: 04/19/2006
• Issued: 09/20/2011
• Est. Priority Date: 04/29/2005
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Martinez, Ruben, Clark, Brian, Taherian, Reza
• Primary Examiner(s): Ye; Lin
• Assistant Examiner(s): Hsu; Amy
• Application Number:
  US11/379,308
• Publication Number:
  US 20060284975A1
• Time in Patent Office: 1,980 Days
• Field of Search: 348 82- 85, 324/367, 175/40, 175/50
• US Class Current: 348/85
• CPC Class Codes: E21B 47/0025 generating an image of the borehole wall using down-hole measurements, e.g. acoustic or electric
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

A borehole imaging tool for use in a wellbore penetrating an earth formation includes a pad hingedly connected to a collar, a sensor array carried by the pad, and an urging assembly in connection between the pad and the collar for extending the pad toward a wall of the wellbore. The imaging tool is compatible with both oil-based and water-based drilling fluids.

Claims

1. A while-drilling borehole imaging tool for use in a wellbore penetrating an earth formation, the tool comprising:

a drill collar;

a pad hingedly connected to the drill collar, wherein the pad is hingedly connected to the drill collar at a pivot point, the pivot point being positioned approximately 90 degrees circumferentially about the drill collar from the pad;

one or more sensors carried by the pad; and

an urging assembly in connection between the pad and the drill collar.

2. The tool of claim 1, wherein the one or more sensors includes at least one array of endfire magnetic dipole antennas, one array of broadside magnetic dipole antennas, or a combination of both.

3. The tool of claim 1, wherein the urging assembly comprises a spring.

4. The tool of claim 1, wherein the pad is maintained less than 0.5 centimeters from a wall of the wellbore.

5. The tool of claim 1, wherein the urging assembly is a hydraulic mechanism.

6. The tool of claim 1, wherein the urging assembly is actuated by a command.

7. The tool of claim 1, wherein the urging assembly includes:

a conduit formed through the drill collar;

a first piston positioned in the conduit in pressure communication with a bore through the drill collar;

a second piston in operational connection with the pad; and

a biasing mechanism interconnecting the first piston and the second piston.

8. The tool of claim 1, further including a stabilizer in operational cooperation with the drill collar.

9. The tool of claim 1, further including wiring passing through the hinged connection of the pad.

10. The tool of claim 1, further including an electronic assembly disposed in the pad.

11. A tool for borehole imaging while drilling and compatible with both conductive and resistive drilling fluids, the tool comprising:

a drill collar;

a pad hingedly connected to the drill collar, wherein the pad is hingedly connected to the drill collar at a pivot point, the pivot point being positioned approximately 90 degrees circumferentially about the drill collar from the pad;

at least one antenna carried by the pad; and

an urging assembly in connection between the pad and the drill collar.

12. The tool of claim 11, further including an electronic assembly disposed in the pad.

13. The tool of claim 11, wherein the at least one antenna includes at least one array of endfire magnetic dipole antennas, one array of broadside magnetic dipole antennas, or a combination of both.

14. The tool of claim 11, wherein the urging assembly is a hydraulic mechanism.

15. The tool of claim 11, wherein the urging assembly is actuated by a command.

16. The tool of claim 11, wherein the urging assembly includes:

a conduit formed through the drill collar;

a first piston positioned in the conduit in pressure communication with a bore through the drill collar;

a second piston in operational connection with the pad; and

a biasing mechanism interconnecting the first piston and the second piston.

17. The tool of claim 11, further including wiring passing through the hinged connection of the pad.

18. The tool of claim 11, wherein the urging assembly comprises a spring.

19. A method of imaging a borehole while drilling, the method comprising:

positioning an imaging tool in a borehole, the imaging tool having a pad hingedly connected to a drill collar at a pivot point, the pivot point being positioned approximately 90 degrees circumferentially about the drill collar from the pad, and one or more sensors carried by the pad;

maintaining the pad during operation at a standoff of 0.5 centimeters or less;

making measurements while maintaining; and

using the measurements to create an image of the borehole.

20. The method of claim 19, wherein the one or more sensors includes at least one array of endfire magnetic dipole antennas, one array of broadside magnetic dipole antennas, or a combination of both.

21. The method of claim 19, further comprising commanding the urging assembly to actuate.

22. A logging-while-drilling tool, comprising:

a drill collar;

a pad moveably connected to the drill collar at a pivot point, the pivot point being positioned approximately 90 degrees circumferentially about the drill collar from the pad;

one or more sensors carried by the pad; and

wiring electrically connected to the one or more sensors and passing through the connection of the pad to the drill collar.

23. A logging-while-drilling tool, comprising:

a drill collar;

a pad moveably connected to the drill collar at a pivot point, the pivot point being positioned approximately 90 degrees circumferentially about the drill collar from the pad;

one or more sensors carried by the pad; and

an electronic assembly disposed in the pad.