Downhole electromagnetic sensing techniques
AssigneeSchlumberger Technology Corporation
InventorsJung Kee Chung, Sameer Bhoite, Dean Homan, Edward Michael Tollefsen, Jaroslav Dobos
Life of this patent
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Abstract
An electromagnetic (EM) telemetry system includes an EM transmitter configured to transmit EM signals downhole and multiple sensors each configured to communicate with the EM transmitter and with another of the multiple sensors. Each sensor is placed a distance from another sensor along a length of a wellbore in the EM telemetry system. The EM telemetry system also includes a processor configured to select two or more sensors of the multiple sensors based on a signal to noise ratio (SNR) of an EM signal received from the two or more selected sensors, a depth of the EM transmitter, or both.
Claims20
An electromagnetic (EM) telemetry system comprising:
- an EM transmitter configured to transmit EM signals downhole;
- multiple sensors each configured to communicate with the EM transmitter and with another of the multiple sensors, wherein each sensor of the multiple sensors is placed a distance from another sensor along a length of a wellbore in the EM telemetry system;
- and
- a processor configured to select two or more sensors of the multiple sensors based on a signal to noise ratio (SNR) of an EM signal received from the two or more selected sensors, a depth of the EM transmitter, or both.
An insulating device configured to electrically insulate sensors in an electromagnetic (EM) telemetry system, the insulating device comprising:
- a first conductive sub and a second conductive sub, each comprising a threaded surface configured to fit with the other;
- an insulation structure between the first and second conductive subs;
- and
- a conductor channel disposed across the insulation structure and between a first electronic pocket in the first conductive sub and a second electronic pocket in the second conductive sub, wherein the conductor channel is configured to alter the electrical potential of the first sub.
An insulating device configured to electrically insulate sensors in an electromagnetic (EM) telemetry system, the insulating device comprising:
- a first conductive sub and a second conductive sub, each comprising a threaded surface configured to fit with the other;
- an insulation structure between the first and second conductive subs;
- and
- a conductor channel disposed through the second conductive sub and through the insulation structure and between the first conductive sub and the second conductive sub, wherein the conductor channel is configured to alter the electrical potential of the first conductive sub.
Dependencies are inferred from the claim text.