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Determination of Shear Wave Velocity and Attenuation From Waveforms in Low Velocity Formations
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
In boreholes where formation shear velocity is lower than borehole fluid velocity neither refracted shear waves nor pseudo-Rayleigh waves can propagate. When frequency response of the sonde does not extend to low frequencies ...
Effects of Casing on Full Waveform Acoustic Logs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1983)
A general expression is derived for the dispersion relations and the impulse response of a radially layered borehole. The. model geometry consists of a central fluid cylinder surrounded by an arbitrary number of solid ...
Full Waveform Acoustic Logging - Where We Are, Where We Are Going
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
We have now completed the second year of the Full Waveform Acoustic Logging Consortium. During these two years, we have developed a good understanding of seismic wave propagation in a borehole through both theoretical ...
Permeability Estimation From Velocity Anisotropy In Fractured Rock
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)
Cracks in a rock mass subjected to a uniaxial stress will be preferentially closed depending on the angle between the fracture normal and the direction of the applied
stress. If the prestress fracture distribution is ...
Laboratory Measurements of Attenuation in Rocks at Ultrasonic Frequencies
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)
The spectral ratio method is used to calculate the quality factor (Q) in porous
rock samples at ultrasonic frequencies (0.3 - 1.5 MHz). The data were collected
using the pulse transmission technique with aluminum used ...
Experimental Determination of Elastic Anisotropy of Berea Sandstone, Chicopee Shale and Chelmsford Granite
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)
We use the ultrasonic transmission method to measure P-, SH-, and SV-wave
velocities for Chelmsford Granite, Chicopee Shale, and Berea Sandstone in different
directions up to 1000 bars confining pressure. The velocity ...
Fracture Detection And Characterization
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1988)
The effects of fractures on full waveform acoustic logs are studied on the basis of field
observations, available theoretical models, and a series of ultrasonic laboratory experiments. Results from diffusion models ...
Detection and Characterization of Fractures from Generation of Tube Waves
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)
Field testing has been conducted to evaluate a model which predicts the
permeability and orientation of a permeable zone, in a deep water well in crystalline
rock. Tube waves are generated by seismic P-waves incident on ...
Determination of Shear Wave Velocities in "Slow" Formations
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1983)
Direct determination of formation shear wave travel time is impossible in "slow" formations where the shear wave velocity is lower than the borehole fluid (mud) velocity. However, the Stoneley waves in these formations are ...
Determination of Formation Properties in Cased Boreholes Using Full Waveform Acoustic Logs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Wave propagation in bonded and unbonded cased boreholes is examined through the calculation cif synthetic full waveform acoustic logs. The models consist of a central fluid borehole surrounded by a number of fluid and solid ...