Use of Lamb and SH attenuations to estimate cement Vp and Vs in cased borehole
First Claim
1. A method of determining properties of a bonding material disposed outside of a casing in a borehole, comprising:
- inducing an SH wave in the casing;
measuring attenuation of the SH wave;
determining the shear velocity or the shear impedance of the bonding material based on the measured attenuation of the SH wave;
inducing a Lamb wave in the casing;
measuring attenuation of the Lamb wave;
generating at least one Lamb attenuation curve that has a value that satisfies the measured attenuation of the Lamb wave; and
determining the compressional velocity or the compressional impedance of the bonding material based on the at least one generated Lamb attenuation curve and the measured attenuation of the Lamb wave.
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Accused Products
Abstract
A method of determining properties of a bonding material disposed outside of a casing in a borehole includes at least two of the following three pairs of operations: (1) inducing an acoustic wave in the casing, and measuring attenuation of the acoustic wave, by pulse-echo or other cement bond logging measurement; (2) inducing an SH wave in the casing, and measuring attenuation of the SH wave; and (3) inducing a Lamb wave in the casing, and measuring attenuation of the Lamb wave. (2) and/or (3) may be performed by an electromagnetic acoustic transducer. The method further includes determining the shear velocity or shear impedance and the compressional velocity or compressional impedance of the bonding material based on appropriate ones of the measurements. The bonding material may be cement.
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Citations
17 Claims
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1. A method of determining properties of a bonding material disposed outside of a casing in a borehole, comprising:
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inducing an SH wave in the casing; measuring attenuation of the SH wave; determining the shear velocity or the shear impedance of the bonding material based on the measured attenuation of the SH wave; inducing a Lamb wave in the casing; measuring attenuation of the Lamb wave; generating at least one Lamb attenuation curve that has a value that satisfies the measured attenuation of the Lamb wave; and determining the compressional velocity or the compressional impedance of the bonding material based on the at least one generated Lamb attenuation curve and the measured attenuation of the Lamb wave. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of determining properties of a bonding material disposed outside of a casing in a borehole, comprising:
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inducing an acoustic wave in the casing; measuring attenuation of the acoustic wave; determining the compressional velocity or compressional impedance of the bonding material based on the measured attenuation of the acoustic wave; inducing a Lamb wave in the casing; measuring attenuation of the Lamb wave; and determining the shear velocity or shear impedance of the bonding material based on (a) the measured attenuation of the Lamb wave and (b) the determined compressional velocity or compressional impedance of the bonding material, wherein the determining of the shear velocity or shear impedance of the bonding material based on (a) the measured attenuation of the Lamb wave and (b) the determined compressional velocity or compressional impedance of the bonding material comprises; generating a Lamb attenuation curve that corresponds to (c) the determined compressional velocity or compressional impedance of the bonding material and (d) multiple shear velocities; and identifying an intersection of the generated Lamb attenuation curve with the measured Lamb attenuation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification