System for measuring stress in downhole tubulars
AssigneeBaker Hughes Incorporated
InventorJoseph Gregory Barolak
Life of this patent
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Abstract
An apparatus for evaluating the possibility of casing failure in a borehole measures azimuthal changes in a property responsive to azimuthal changes in axial stress. The measurements may be of acoustic velocity, magnetic permeability, and Barkhausen noise.
Claims11
An apparatus for determining an azimuthal stress variation in a tubular within a borehole, the apparatus comprising:
- a logging tool including at least one transducer configured to generate a wave in the tubular;
- a plurality of acoustic receivers azimuthally distributed in the logging tool, each of the acoustic receivers configured to produce a signal responsive to the generated wave and an azimuthal stress variation in the tubular;
- and
- at least one processor;
- and
- instructions on a non-transitory medium accessible to the at least one processor;
- wherein the at least one processor is configured to execute the instructions to determine from the signal from each of the plurality of acoustic receivers an indication of the azimuthal stress variation in the tubular.
The apparatus of clam 1 wherein each of the plurality of acoustic receivers further comprises an electromagnetic receiver mounted on a pad extendable from a body of the logging tool and wherein the signal produced by each of the plurality of electromagnetic receivers is indicative of a magnetic permeability of the tubular.
An apparatus for determining an azimuthal stress variation in a tubular within a borehole, the apparatus comprising:
- a logging tool including at least one transducer configured to generate a wave in the tubular;
- a plurality of magnetic field sensors azimuthally distributed in the logging tool, each of the magnetic field sensors configured to produce a signal responsive to an azimuthal stress variation in the tubular and at least one of:
- (i) a Barkhausen noise produced by a magnet on the tool and (ii) a current in an axially oriented transmitter coil;
- and
- at least one processor;
- and
- instructions on a non-transitory medium accessible to the at least one processor;
- wherein the at least one processor is configured to execute the instructions to determine from the signal from each of the plurality of magnetic field sensors an indication of the azimuthal stress variation in the tubular.
Dependencies are inferred from the claim text.