Seismic exploration in areas where P waves are converted to S waves
A method is described of enhancing seismic sections of areas containing subsurface formations which generate shear wave reflections from longitudinal wave excitation, comprising: generating seismic energy and detecting reflections of the energy with a plurality of offsets between the source and detector to produce a plurality of field seismograms, which include reflections from asymmetrical, common reflection points where there is a conversion between longitudinal and shear waves; determining the velocity of the energy in the earth formations to the asymmetrical common reflection points; determining the asymmetrical reflection point for the field seismograms from the velocity determined in the preceding step and from the course to detector offset for the seismogram; gathering the field seismograms into sets having reflections from the asymmetrical common reflection points; determining the velocity of the energy in the earth formations from the gathered sets of field seismograms; normal moveout correcting the gathered sets of field seismograms using the velocity determinations from the preceding steps; enhancing the gathered sets of seismograms to correct for non-surface consistent static time shifts; and stacking the sets to produce a seismic section which emphasizes the reflections from the asymmetrical reflection points at which there is a conversion between longitudinal waves and shear waves.
- Assignee:
- Mobil Oil Corp., New York, NY
- Patent Number(s):
- US 4604734
- OSTI ID:
- 5312591
- Country of Publication:
- United States
- Language:
- English
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03 NATURAL GAS
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ASYMMETRY
DATA ACQUISITION
EXPLORATION
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
MEASURING INSTRUMENTS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
PHASE VELOCITY
REFLECTION
RESOURCES
SEISMIC ARRAYS
SEISMIC DETECTORS
SEISMIC P WAVES
SEISMIC S WAVES
SEISMIC SOURCES
SEISMIC SURVEYS
SEISMIC WAVES
SEISMOGRAPHS
SURVEYS
TIME DEPENDENCE
VELOCITY
WAVE PROPAGATION