Method for magnetizing casing string tubulars
AssigneeSmith International, Inc.
InventorsKenneth Stenerson, Leon Ceh, Graham A. McElhinney
Life of this patent
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Abstract
A method for magnetizing a wellbore tubular includes a positioning a wellbore tubular substantially coaxially in a plurality of longitudinally spaced magnetizing coils deployed on a frame. The coils are selectively connected and disconnected from electrical power such that a circumferential electrical current flows in each of the coils to impart a predetermined magnetic field pattern to the tubular. Exemplary embodiments of this invention provide for semi-automated control of tubular magnetization and thereby enable a repeatable magnetic pattern to be imparted to each of a large number of wellbore tubulars.
Claims20
A method of magnetizing a wellbore tubular, the method comprising:
- (a) positioning a wellbore tubular substantially coaxially in a plurality of longitudinally spaced magnetizing coils deployed on a frame via driving the tubular in an axial direction along a track of non-magnetic rollers with an electric motor;
- (b) connecting the plurality of magnetizing coils to an electrical power source such that a circumferential non-alternating electrical current flows in a clockwise direction about the wellbore tubular in a first subset of the coils and in a counterclockwise direction about the wellbore tubular in a second subset of the coils so as to impart a predetermined magnetic field pattern to the wellbore tubular having at least one pair of opposing magnetic poles;
- (c) disconnecting the magnetizing coils from the electrical power source;
- and
- (d) removing the wellbore tubular from the coils via driving the tubular in an axial direction along a track of non-magnetic rollers with an electric motor.
A method of magnetizing a wellbore tubular, the method comprising:
- (a) positioning a wellbore tubular substantially coaxially in a plurality of longitudinally spaced magnetizing coils deployed on a frame via driving the tubular in an axial direction along a track of non-magnetic rollers with an electric motor;
- (b) connecting the plurality of magnetizing coils to an electrical power source such that a circumferential non-alternating electrical current flows in each of the coils to impart a predetermined magnetic field pattern to the tubular;
- (c) disconnecting the magnetizing coils form the electrical power source;
- (d) removing the wellbore tubular from the magnetizing coils via driving the tubular in an axial direction along a track of non-magnetic rollers with an electric motor;
- (e) measuring a magnetic field along a length of the wellbore tubular as the tubular is moved axially relative to a magnetic field sensor while being removed in (d);
- and
- (f) processing the magnetic field measured in (e) to determine whether or not the magnetic field pattern imparted in (b) is within predetermined limits.
A method of magnetizing a wellbore tubular, the method comprising:
- (a) positioning a wellbore tubular substantially coaxially in a plurality of longitudinally spaced magnetizing coils deployed on a frame;
- (b) connecting the plurality of magnetizing coils to an electrical power source such that a circumferential non-alternating electrical current flows in a clockwise direction about the wellbore tubular in a first subset of the coils and in a counterclockwise direction about the wellbore tubular in a second subset of the coils so as to impart a predetermined magnetic field pattern to the wellbore tubular having at least one pair of opposing magnetic poles;
- (c) disconnecting the magnetizing coils from the electrical power source;
- and
- (d) removing the wellbore tubular from the coils and measuring a magnetic field along a length of the tubular as the tubular is moved axially relative to a magnetic field sensor;
- and
- (e) processing the magnetic field measured in (d) to determine whether or not the magnetic field pattern imparted in (b) is within predetermined limits.
Dependencies are inferred from the claim text.