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Detection of Open Fractures with Vertical Seismic Profiling
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984-01-01)
In Vertical Seismic Profiling surveys tube waves are generated by compressional waves impinging on subsurface fractures or permeable zones. The problem of generation of these waves by a non-normal incident P wave for an ...
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 ...
Nullerical Studies of Body Wave Amplitudes in Full Waveform Acoustic Logs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
The amplitudes of P and S head waves in a full waveform acoustic log microseismogram are studied numerically as a function of borehole and formation parameters. The technique used is contour integration around the respective ...
Field Test of a Low-Frequency Sparker Source for Acoustic Waveform Logging
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Low-frequency acoustic-energy sources for waveform logging have important applications in: 1) Verifying theoretical calculations; 2) generating tube waves in large-diameter boreholes; and 3) providing larger sample volumes ...
Analysis of Full Waveform Acoustic Logging Data in "Soft" Formations
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Direct recording of formation shear wave travel time is not possible in "soft" formations where the shear velocity is lower than the borehole fluid velocity. The borehole Stoneley wave is quite sensitive to changes in ...
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 ...
Application of Full Waveform Acoustic Logging Data to the Estimation of Reservoir Permeability
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Development of borehole geophysics has recently focused on reservoir characterization. Within this effort, extensive full waveform acoustic surveys have demonstrated a correlation between the occurance of open fractures ...
Applications of Finite Difference Synthetic Acoustic Logs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Finite difference synthetic acoustic logs are suitable for studying wave propagation in vertically varying boreholes and in boreholes with continuously varying properties. Snapshots for the traditional smooth bore in a ...
The Study of Wave Propagation in a Borehole Using the Finite Difference Method
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
Synthetic microseismograms of elastic wave propagation in a fluid-filled borehole were generated using both the finite difference technique and the discrete wavenumber summation technique. For the finite difference ...
Dispersion Curves and Synthetic Microseismograms in Unbonded Cased Boreholes
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
The dispersion relations and impulse response. are calculated for a geometry consisting of an arbitrary number of coaxial annuli surrounding a central cylinder. The annuli may be either solid or fluid. The formulation ...