Modular resistivity sensor for downhole measurement while drilling

摘要

A modular resistivity sensor disposable in a drillstring having a drill bit on a distal end for drilling a wellbore in a formation, includes a sensor body having a longitudinal axis radially offset from a longitudinal axis of the drillstring, one or more transmitting coil antennas disposed along a length of the sensor body, one or more receiving coil antennas disposed along a length of the sensor body, and a calibrating device configured to calibrate signals generated from the receiving coil antennas.

主权项

1. A resistivity sensor comprising:
a sensor body having a longitudinal axis, wherein the sensor body is disposable in and separable from a tool body in a drillstring; one or more transmitting coil antennas disposed along a length of the sensor body; one or more receiving coil antennas disposed along a length of the sensor body; a calibrating device configured to calibrate signals generated from the receiving coil antennas, and an electronics section contained within the sensor body for generating and receiving signals to and from the transmitting and receiving coil antennas, wherein the longitudinal axis of the sensor body is radially offset from a longitudinal axis of the tool body, and thereby when the tool body rotates, transmitting and receiving patterns from the coil antennas disposed along a length of the sensor body rotate with the tool body.