NMR-LWD imaging tool
First Claim
1. An apparatus for estimating a nuclear magnetic resonance (NMR) property of an earth formation penetrated by a borehole, the apparatus comprising:
- a logging tool;
a source of a static magnetic field, the source being disposed at the logging tool and configured to polarize the region of investigation in the earth formation;
a transmitter antenna disposed at the logging tool and configured to transmit electromagnetic energy into the region of investigation;
a first receiver sensor disposed at the logging tool and configured to receive first NMR signals in an azimuthal direction with respect to a longitudinal axis of the logging tool from the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy;
a second receiver sensor disposed at the logging tool and configured to receive second NMR signals in an azimuthal direction with respect to the longitudinal axis of the logging tool from the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy; and
a processor configured to;
receive the first NMR signals from the first receiver sensor;
associate the first NMR signals with a first azimuthal direction at which the first NMR signals were received;
receive the second NMR signals from the second receiver sensor;
associate the second NMR signals with a second azimuthal direction at which the second NMR signals were received, wherein second azimuthal direction is different from the first azimuthal direction; and
estimate the property from the first and second NMR signals and the associated azimuthal directions at which the first and second NMR signals were received.
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Accused Products
Abstract
An apparatus for estimating a nuclear magnetic resonance (NMR) property of an earth formation penetrated by a borehole, the apparatus including: a logging tool having a source of a static magnetic field configured to polarize a region of investigation in the earth formation; a transmitter antenna disposed at the logging tool and configured to transmit electromagnetic energy into the region of investigation; at least one receiver sensor disposed at the logging tool and configured to receive NMR signals from the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy; and a processor configured to: receive the NMR signals from the at least one receiver sensor; associate the NMR signals received from the at least one receiver sensor with an azimuthal direction at which the NMR signals were received; and estimate the property from the NMR signals and the associated azimuthal directions.
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Citations
21 Claims
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1. An apparatus for estimating a nuclear magnetic resonance (NMR) property of an earth formation penetrated by a borehole, the apparatus comprising:
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a logging tool; a source of a static magnetic field, the source being disposed at the logging tool and configured to polarize the region of investigation in the earth formation; a transmitter antenna disposed at the logging tool and configured to transmit electromagnetic energy into the region of investigation; a first receiver sensor disposed at the logging tool and configured to receive first NMR signals in an azimuthal direction with respect to a longitudinal axis of the logging tool from the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy; a second receiver sensor disposed at the logging tool and configured to receive second NMR signals in an azimuthal direction with respect to the longitudinal axis of the logging tool from the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy; and a processor configured to; receive the first NMR signals from the first receiver sensor; associate the first NMR signals with a first azimuthal direction at which the first NMR signals were received; receive the second NMR signals from the second receiver sensor; associate the second NMR signals with a second azimuthal direction at which the second NMR signals were received, wherein second azimuthal direction is different from the first azimuthal direction; and estimate the property from the first and second NMR signals and the associated azimuthal directions at which the first and second NMR signals were received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for estimating a nuclear magnetic resonance (NMR) property of an earth formation penetrated by a borehole, the method comprising:
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conveying a logging tool through the borehole; generating a static magnetic field in a region of investigation in the earth formation with the logging tool; transmitting electromagnetic energy into the region of investigation with the logging tool; receiving first NMR signals in a first azimuthal direction with respect to a longitudinal axis of the logging tool with a first receiver sensor disposed at the logging tool from the region of investigation in response to an interaction between NMR spins and the static magnetic field and the transmitted electromagnetic energy; receiving second NMR signals in a second azimuthal direction with respect to the longitudinal axis of the logging tool with a second receiver sensor disposed at the logging tool from the region of investigation in response to an interaction between NMR spins and the static magnetic field and the transmitted electromagnetic energy, wherein the second azimuthal direction is different from the first azimuthal direction; associating the first NMR signals with the first azimuthal direction and the second NMR signals with the second azimuthal direction; and estimating the property from the first and second NMR signals and the associated azimuthal directions at which the first and second NMR signals were received. - View Dependent Claims (18, 19, 20)
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21. A non-transitory machine-readable medium comprising machine-executable instructions for estimating a nuclear magnetic resonance (NMR) property of an earth formation penetrated by a borehole having a logging tool disposed therein by implementing a method comprising:
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receiving first NMR signals in a first azimuthal direction with respect to a longitudinal axis of the logging tool with a first receiver sensor disposed at the logging tool from a region of investigation in the earth formation; receiving second NMR signals in a second azimuthal direction with respect to a longitudinal axis of the logging tool with a second receiver sensor disposed at the logging tool from the region of investigation, wherein the second azimuthal direction is different from the first azimuthal direction; associating the first NMR signals with the first azimuthal direction and the second NMR signals with the second azimuthal direction; and estimating the property from the first and second NMR signals and the associated azimuthal directions at which the first and second NMR signals were received.
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Specification