Method of attenuating unwanted seismic reflections in underwater seismic exploration
AssigneeAvance Oil & Gas Company, Inc.
InventorVearle Spurlock Balderson
Life of this patent
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Abstract
A string of seismic detectors is towed at a certain depth underwater by a survey boat over an area to be explored. A seismic disturbance is produced at a distance below the surface of the water such that the propagation time of seismic waves traveling from the disturbance and reflected from the water surface to the detectors is substantially the same as the propagation time of seismic waves traveling from the disturbance and reflected from the water floor to the detectors. Since the seismic waves reflected from the water surface are out of phase with those reflected from the water floor, the reflected waves tend to cancel or attenuate, thereby eliminating or minimizing these unwanted seismic signals.
Claims3
A method of conducting seismic exploration in water covered areas comprising:
- positioning a seismic detector below the surface and above the bottom of a water layer at about the seismic wave time center,
- producing a seismic disturbance below the surface of the water at about the seismic wave time center which generates seismic waves which will penetrate and be reflected from subsurface strata and also be reflected between the surface and bottom of the water layer to produce reverberations,
- detecting the reflected seismic waves in said seismic detector, said seismic detector being of a character that reflections of a seismic wave from the surface and bottom of the water layer will cancel and only be detected at reduced amplitudes, and
- recording the detected seismic energy.
Dependencies are inferred from the claim text.