Communications – electrical: acoustic wave systems and devices – Seismic prospecting – Well logging
Patent
1982-10-15
1986-03-11
Cangialosi, Salvatore
Communications, electrical: acoustic wave systems and devices
Seismic prospecting
Well logging
364422, 367 27, 367 31, 367 75, G01V 140
Patent
active
045758301
ABSTRACT:
A method and apparatus for estimating shear wave velocities where such velocities are difficult or impossible to measure because the shear energy transmission is attenuated or its velocity is equal to or less than direct mud velocity or because the shear wave may not propagate at all under certain conditions. The method and apparatus relate to an indirect technique for determining shear modulus by measuring the phase velocity of the Stoneley wave excitation and using it to estimate the shear modulus and the shear velocity. Using at least two receivers, a window is placed over the Stoneley arrival of the wave detected at each receiver and the Fourier transform of each wave is taken. The difference in phase of the Stoneley wave arrivals is determined. The relative shear modulus involving the Lame constants is estimated by a procedure which includes matching two points on Stoneley wave dispersion curves. From the relative shear modulus, the ratio of formation density to the density of mud, and the compressional velocity of the borehole mud is estimated the shear velocity.
REFERENCES:
patent: 4210965 (1980-07-01), Ingram
patent: 4210966 (1980-07-01), Ingram
Hamilton, "Elastic Properties of Marine Sediments", J. of Geophysical Research, Jan. 10, 1971, vol. 76, No. 2, pp. 579-603.
Clay et al., "Use of a Two-Dimensional Array to Receive an Unknown Signal in a Dispersive Waveguide", J. of the Acoustical Society of Amer., vol. 47, No. 2, (1970) pp. 435-440.
Cheng et al., "Velocity and Attenuation from Full Waveform Acoustic Logs", SPWLA 22nd Annual Logging Symposium, Jun. 23-26, 1981, pp. 1-19.
Biot, "Propagation of Elastic Waves in a Cylindrical Bore Containing a Fluid", vol. 23, No. 9, Sep. 1952, pp. 997-1005.
Koerperich, "Shear Wave Velocities Determined from Long and Short Spaced Borehole Acoustic Devices", SPE 54th Annual Fall Tech. Conf. and Exhib., Las Vegas, Nevada, Sep. 23-26, 1979.
Piersol, "Time Delay Estimation Using Phase Data", IEEE Transactions on Acoustics, Speech and Signal Processing, vol. ASSP-29, No. 3 (Jun. 1981).
Aron et al., "Formation Compressional and Shear Interval-Transit-Time Logging by Means of Long Spacings and Digital Techniques, Tech. Paper, 53rd Annual Fall Tech Conf and Exhib of SPE, Oct. 1-3, 1978.
Ingram John D.
Murray Josephine L.
Cangialosi Salvatore
Kaiser K. R.
Schlumberger Technology Corporation
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