Magnetization of target well casing strings tubulars for enhanced passive ranging
AssigneePathFinder Energy Services, Inc.
InventorGraham McElhinney
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Abstract
A method for magnetizing a wellbore tubular is disclosed. The method includes magnetizing a wellbore tubular at three or more discrete locations on the tubular. In exemplary embodiments the magnetized wellbore tubular includes at least one pair of opposing magnetic poles located between longitudinally opposed ends of the tubular. Wellbore tubulars magnetized in accordance with this invention may be coupled to one another to provide a magnetic profile about a section of a casing string. Passive ranging measurements of the magnetic field about the casing string may be utilized to survey and guide drilling of a twin well. Such an approach advantageously obviates the need for simultaneous access to both wells.
Claims50
A method for creating a magnetic profile around a plurality of wellbore tubulars, the magnetic profile operable to enhance subsequent passive ranging techniques, the method comprising:
- (a) magnetizing a wellbore tubular at three or more locations along a length of the tubular;
- and,
- (b) repeating (a) for each of the plurality of wellbore tubulars.
A method for creating a magnetic profile around a length of coupled wellbore tubulars, the magnetic profile operable to enhance subsequent passive ranging techniques, the method comprising:
- (a) magnetizing a tubular at three or more locations along a length of the tubular, such that the magnetized tubular includes at least one pair of opposing magnetic poles located between the longitudinally opposed ends thereof;
- (b) repeating (a) for each of a plurality of wellbore tubulars;
- and
- (c) coupling at least two of the magnetized wellbore tubulars to one another.
A method for creating a magnetic profile around a wellbore tubular, the magnetic profile operable to enhance subsequent passive ranging techniques, the method comprising:
- (a) providing a magnetic field generating device in proximity with a wellbore tubular, the magnetic field generating device producing magnetic flux that intersects at least a portion of the wellbore tubular;
- and
- (b) creating relative motion between the magnetic field generating device and the wellbore tubular along at least a portion of a length of the wellbore tubular, such that the magnetic field generating device magnetizes at least two discrete portions of the wellbore tubular, the at least two discrete portions providing at least one pair of opposing magnetic poles located between longitudinally opposed ends of the wellbore tubular.
A method for surveying a borehole having a known or predictable magnetic profile, said profile resulting from controlled magnetization of wellbore tubulars, the method comprising:
- (a) positioning a downhole tool having a magnetic field measurement device in the borehole, said tool positioned within sensory range of a magnetic field from a target well, wherein
- (i) the target well comprises a plurality of magnetized wellbore tubulars positioned in the target well, each magnetized wellbore tubular having at least one pair of opposing magnetic poles located between longitudinally opposed ends of the wellbore tubular, and said magnetized wellbore tubulars coupled to one another;
- (b) measuring a local magnetic field using the magnetic field measurement device;
- and,
- (c) processing the local magnetic field measured in (b) to determine at least one of (i) a distance or (ii) a direction from the borehole to the target well.
A method of drilling substantially parallel twin wells, the method comprising:
- (a) drilling a first well;
- (b) deploying a casing string in the first well, a magnetized section of the casing string including a plurality of magnetized wellbore tubulars, the magnetized section of the casing string further including a plurality of pairs of opposing magnetic poles, the opposing magnetic poles having an average longitudinal spacing of less than a length of the magnetized wellbore tubulars;
- (c) drilling a portion of a second well, the portion of the second well located within sensory range of magnetic flux from the magnetized section of the casing string;
- (d) measuring a local magnetic field in the second well;
- (e) processing the local magnetic field measured in (d) to determine a direction for subsequent drilling of the second well;
- and
- (f) drilling the second well along the direction for subsequent drilling determined in (e).
Dependencies are inferred from the claim text.