MWD/LWD NMR IMAGING WITH LONG ECHO TRAINS
First Claim
1. An apparatus for estimating a 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 a region of investigation;
a transmitter antenna disposed at the logging tool and configured to transmit a train of pulses of electromagnetic energy into the region of investigation;
a plurality of receiver antennas disposed at the logging tool and configured to receive nuclear magnetic resonance (NMR) signals from a plurality of angular segments in the region of investigation in response to an interaction between the static magnetic field and the pulses of electromagnetic energy; and
a processor configured to;
receive the NMR signals from each receiver antenna, the NMR signals comprising first NMR signals received from an angular segment by one receiver antenna and second NMR signals received from the angular segment by at least two receiver antennas;
associate the first NMR signals and the second NMR signals with the angular segment from which the first NMR signals and the second NMR signals were obtained;
deconvolve the second NMR signals to produce deconvolved NMR signals; and
estimate the property from the first NMR signals, the deconvolved NMR signals, and the associated angular segments.
1 Assignment
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Accused Products
Abstract
An apparatus for estimating a property of an earth formation having: a plurality of receiver antennas to receive nuclear magnetic resonance (NMR) signals from a plurality of angular segments in a region of investigation in response to an interaction between a static magnetic field and pulses of electromagnetic energy; and a processor configured to: receive the NMR signals from each receiver antenna, the NMR signals having first NMR signals received from each angular segment by only one receiver antenna and second NMR signals received from a same angular segment by at least two receiver antennas; associate the first NMR signals and the second NMR signals with the angular segment from which the first NMR signals and the second NMR signals were obtained; deconvolve the second NMR signals to produce deconvolved NMR signals; and estimate the property from the first NMR signals, the deconvolved NMR signals, and the associated angular segments.
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Citations
16 Claims
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1. An apparatus for estimating a 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 a region of investigation; a transmitter antenna disposed at the logging tool and configured to transmit a train of pulses of electromagnetic energy into the region of investigation; a plurality of receiver antennas disposed at the logging tool and configured to receive nuclear magnetic resonance (NMR) signals from a plurality of angular segments in the region of investigation in response to an interaction between the static magnetic field and the pulses of electromagnetic energy; and a processor configured to; receive the NMR signals from each receiver antenna, the NMR signals comprising first NMR signals received from an angular segment by one receiver antenna and second NMR signals received from the angular segment by at least two receiver antennas; associate the first NMR signals and the second NMR signals with the angular segment from which the first NMR signals and the second NMR signals were obtained; deconvolve the second NMR signals to produce deconvolved NMR signals; and estimate the property from the first NMR signals, the deconvolved NMR signals, and the associated angular segments. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for estimating a 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, the static magnetic field being configured to polarize the region of investigation; transmitting electromagnetic energy into the region of investigation with the logging tool; receiving nuclear magnetic resonance (NMR) signals with a plurality of receiver antennas disposed at the logging tool from angular segments in the region of investigation in response to an interaction between the static magnetic field and the transmitted electromagnetic energy, the NMR signals comprising first NMR signals received from an angular segment by one receiver antenna and second NMR signals received from the angular segment by at least two receiver antennas; associating the first NMR signals and the second NMR signals with the angular segment from which the first NMR signals and the second NMR signals were received; deconvolving the second NMR signals to produce deconvolved NMR signals; and estimating the property from the first NMR signals, the deconvolved NMR signals, and the associated angular segments. - View Dependent Claims (13, 14, 15)
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16. A machine-readable medium comprising machine-executable instructions for estimating a property of an earth formation penetrated by a borehole by implementing a method comprising:
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receiving nuclear magnetic resonance (NMR) signals with a plurality of receiver antennas from a region of investigation in the earth formation comprising a plurality of angular segments, the NMR signals comprising first NMR signals received from an angular segment by one receiver antenna and second NMR signals received from the angular segment by two receiver antennas; associating the first NMR signals and the second NMR signals with the angular segment from which the first NMR signals and the second NMR signals were received; deconvolving the second NMR signals to produce deconvolved NMR signals; and estimating the property from the first NMR signals, the deconvolved NMR signals, and the associated angular segments.
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Specification