Method and apparatus for measuring characteristics of geological formations
First Claim
1. A method for determining a conductive tubular correction constant for use in electromagnetic induction tomography in a borehole lined with a conductive tubular, comprising:
- generating a magnetic field inside a representative piece of the conductive tubular;
determining a first magnetic field amplitude inside the representative piece of the conductive tubular at a location proximate to a position of the generating the magnetic field;
determining a second magnetic field amplitude outside the representative piece of the conductive tubular; and
deriving the conductive tubular correction constant from a ratio of the first magnetic field amplitude and the second magnetic field amplitude.
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Abstract
An electromagnetic tomography system for determining properties of geological formation penetrated by at least one borehole lined with a conductive tubular includes a transmitter disposed in a first borehole and adapted to induce a magnetic field, a first receiver disposed in the first borehole and adapted to detect a magnetic field induced in the conductive tubular by the transmitter, and a second receiver adapted to detect a magnetic field induced in the geological formation by the transmitter. A method for determining a conductive tubular correction constant includes generating a magnetic field inside a representative piece of the conductive tubular, determining a first magnetic field amplitude inside the representative piece of the conductive tubular at a location proximate to a position of the generating a magnetic field, determining a second magnetic field amplitude outside the representative piece of the conductive tubular, and deriving the conductive tubular correction constant from a ratio of the first magnetic field amplitude and the second magnetic field amplitude.
38 Citations
14 Claims
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1. A method for determining a conductive tubular correction constant for use in electromagnetic induction tomography in a borehole lined with a conductive tubular, comprising:
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generating a magnetic field inside a representative piece of the conductive tubular;
determining a first magnetic field amplitude inside the representative piece of the conductive tubular at a location proximate to a position of the generating the magnetic field;
determining a second magnetic field amplitude outside the representative piece of the conductive tubular; and
deriving the conductive tubular correction constant from a ratio of the first magnetic field amplitude and the second magnetic field amplitude. - View Dependent Claims (2)
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3. A method for determining a conductive tubular correction constant for use in electromagnetic induction tomography in a borehole lined with a conductive tubular, comprising:
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generating a first magnetic field inside a representative piece of the conductive tubular;
determining an amplitude of a first magnetic field inside the representative piece of the conductive tubular at a location proximate to a position of the generating the first magnetic field;
determining an amplitude of a second magnetic field inside the representative piece of the conductive tubular, the second magnetic field being generated outside the representative piece of the conductive tubular; and
deriving the conductive tubular correction constant from a ratio of the first magnetic field amplitude and the second magnetic field amplitude. - View Dependent Claims (4)
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5. A method for determining properties of a geological formation penetrated by at least one borehole lined with a conductive tubular, comprising:
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generating a magnetic field inside a representative piece of the conductive tubular;
determining a first magnetic field amplitude inside the representative piece of the conductive tubular at a location proximate to a position of the generating the magnetic field inside the representative piece of the conductive tubular;
determining a second magnetic field amplitude outside the representative piece of the conductive tubular;
deriving a conductive tubular correction constant from a ratio of the first magnetic field amplitude and the second magnetic field amplitude;
generating a magnetic field in the geological formation from within the at least one borehole;
measuring a reference magnetic field amplitude inside the at least one borehole;
measuring a formation magnetic field amplitude at a distance from a position of the generating the magnetic field in the geological formation selected so that the formation magnetic field amplitude is related to the magnetic field strength in the geological formation;
correcting the reference magnetic field amplitude measurement and the formation magnetic field amplitude measurement using the conductive tubular correction constant; and
deriving a formation property from the corrected reference magnetic field amplitude measurement and the corrected formation magnetic field amplitude measurement. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification