Integrated Electrode Resistivity and EM Telemetry Tool

• US 20080156534A1
• Filed: 12/28/2006
• Published: 07/03/2008
• Est. Priority Date: 12/28/2006
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Clark, Brian, Smits, Jan W.
• Granted Patent: US 7,782,060 B2
• Time in Patent Office: Days
• US Class Current: 175/45
• CPC Class Codes: E21B 47/01 Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
• CPC Class Codes: E21B 47/113 using electrical indications; using light radiations
• CPC Class Codes: E21B 49/00 Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
• CPC Class Codes: G01V 11/002 Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B

Abstract

An integrated electrode resistivity and EM telemetry tool and obtaining both formation resistivity and telemetry data from the integrated tool. An integrated electrode resistivity and EM telemetry tool having a drill collar including a first portion and a second portion separated by an insulated gap and telemetry cartridge carrying telemetry circuitry including a voltage source generating a voltage drop across the insulated gap and an axial current on a drill string that returns through an earthen formation includes an insulated measure electrode connected to the first portion, and resistivity measurement circuitry functionally connected to the measure electrode and the telemetry circuitry.

Claims

1-22. -22. (canceled)

28. A resistivity tool for use in a wellbore, comprising:

a drill collar including an upper portion and a lower portion separated by an insulated gap;

a measure electrode carried on the drill collar; and

a sense electrode proximate to the measure electrode and carried on the portion of the drill collar on which the measure electrode is carried.

29. The tool of claim 28, further comprising an ac voltage source to provide a voltage difference across the insulated gap.

30. The tool of claim 29, wherein the ac voltage source can operate at multiple frequencies.

31. The tool of claim 28, further comprising an electronics cartridge disposed in the drill collar.

32. The tool of claim 31, wherein the electronics cartridge is retrievable.

33. The tool of claim 28, wherein the measure electrode includes a ring electrode, a burton electrode, or any combination thereof.

34. The tool of claim 33, wherein the measure electrode is a button electrode and the sense electrode is a ring surrounding the button electrode.

35. The tool of claim 33, wherein the measure electrode is a ring electrode and the sense electrode comprises two sense rings, wherein one sense ring is above the ring electrode and the other sense ring is below the ring electrode.

36. The tool of claim 28, further comprising a resistivity measurement circuitry functionally connected to the measure electrode and the sense electrode.

37. The tool of claim 36, wherein the resistivity measurement circuitry maintains the measure electrode at substantially the same potential as the sense electrode and the portion of the drill collar on which the measure electrode is carried.

38. The tool of claim 36, wherein the resistivity measurement circuitry includes a high input impedance amplifier measuring the voltage difference between the sense electrode and the measure electrode and driving the current on the measure electrode such that the voltage difference is zero.

39. The tool of claim 28, wherein the lower portion comprises all or a portion of a bottom hole assembly, the bottom hole assembly comprising various downhole tools.

40. The tool of claim 39, wherein the bottom hole assembly comprises a sub and the sub carries the measure electrode, the sensor electrode, and a resistivity measurement circuitry.

41. The tool of claim 40, wherein the insulated gap and the sub are separated by some distance, the distance being selected to produce a desired depth of investigation for the resistivity measurement.

42. The tool of claim 39, wherein the measure electrode, the sense electrode, and a resistivity measurement circuitry are part of one or more of the downhole tools.

43. A resistivity tool for use in a wellbore, comprising:

a drill collar including an upper portion and a lower portion separated by an insulated gap;

a driving circuitry to produce a voltage difference across the insulated gap; and

a measurement sub having a measure electrode and a measurement circuitry.

44. The tool of claim 43, wherein the driving circuitry can operate at multiple frequencies.

45. The tool of claim 43, wherein the driving circuitry is retrievable.

46. The tool of claim 43, wherein the measure electrode includes a ring electrode, a button electrode, or any combination thereof.

47-58. -58. (canceled)