Subsurface Electromagnetic Measurements using Cross-Magnetic Dipoles
AssigneeSchlumberger Technology Corporation
InventorsDean M. Homan, Dzevat Omeragic, Tianhua Zhang, Nicolas Sebline
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Abstract
Sensor assemblies including transmitter and receiver antennas to respectively transmit or receive electromagnetic energy. The sensor assemblies are disposed in downhole tools adapted for subsurface disposal. The receiver is disposed at a distance less than six inches (15 cm) from the transmitter on the sensor body. The sensor transmitter or receiver includes an antenna with its axis tilted with respect to the axis of the downhole tool. A sensor includes a tri-axial system of antennas. Another sensor includes a cross-dipole antenna system.
Claims20
1-18. (canceled)
A method for determining subsurface properties using a tool adapted for disposal within a borehole traversing an earth formation, the tool having an elongated body with a longitudinal axis and including a transmitter and a receiver disposed thereon, the receiver located at a distance less than six inches (15 cm) from the transmitter, the transmitter or receiver comprising at least one antenna with its axis tilted with respect to the tool axis, comprising:
- a) disposing the tool within the borehole;
- b) energizing the transmitter to emit electromagnetic energy;
- c) acquiring a subsurface electromagnetic measurement using the receiver;
- and
- d) determining a subsurface property using the electromagnetic measurement.
Dependencies are inferred from the claim text.