Modular resistivity sensor for downhole measurement while drilling
AssigneeWell Resolutions Technology
InventorsTsili WANG, Borislav J. TCHAKAROV
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Abstract
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.
Claims20
A modular resistivity sensor disposable in a drillstring having a drill bit on a distal end for drilling a wellbore in a formation, the sensor comprising:
- 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.
A method of making resistivity measurements of a formation from a wellbore being drilled by a tool having a drill bit disposed on a distal end, the method comprising:
- providing a modular resistivity sensor comprising at least one transmitting coil antenna, one or more receiving coil antennas, and a calibrating coil antenna located longitudinally between the receiving coil antennas;
- firing the at least one transmitting coil antenna for generating a current loop in the formation, thereby inducing a first set of independent voltage signals in the receiving coil antennas related to a parameter of the formation;
- firing the calibrating antenna at a desired frequency, thereby inducing a second set of independent voltage signals in the receiving coil antennas;
- and
- calibrating the first set of independent voltage signals relative to the second set of voltage signals.
A method of making resistivity measurements of a formation from a wellbore being drilled by a tool having a drill bit disposed on a distal end, the method comprising:
- providing a modular resistivity sensor comprising at least one transmitting coil antenna, one or more receiving coil antennas, and a calibrating signal generator;
- firing the at least one transmitting coil antenna for generating a current loop in the formation, thereby inducing independent voltage signals in the receiving coil antennas related to a parameter of the formation;
- generating a voltage signal at a desired frequency in the calibrating signal generator;
- transmitting the generated voltage signal to electronics coupled to the receiving antennas;
- and
- calibrating the independent voltage signals induced in the receiving coil antennas.
Dependencies are inferred from the claim text.