Method of seismic surveying, a marine vibrator arrangement, and a method of calculating the depths of seismic sources
AssigneeW'etsern Geco L.I.
InventorsRobert Laws, Stephen Patrick Morice
Life of this patent
Estimating the term…
Abstract
A method of seismic surveying comprises emitting seismic energy at two or more different depths during a sweep. In one embodiment, the depth of a seismic source is varied during a sweep, by raising or lower the source while it is emitting seismic energy. In another embodiment, an array of two or more marine vibrators is used as the source of seismic energy, with the vibrators in the array being disposed at different depths. The invention allows notch frequencies in the amplitude spectrum to be eliminated, and allows improvements in both the spectral flatness and the amplitude at low frequencies.
Claims16
A method of seismic surveying using one or more marine vibrators, the method comprising:
- emitting seismic energy at two or more different depths during a sweep;
- and
- determining the preferred depths, the determination including:
- a) assigning a depth to each seismic source in the array;
- b) for each seismic source in the array, obtaining the amplitude spectrum of seismic energy emitted by the seismic source;
- c) summing the results of step (b) to obtain the amplitude spectrum of seismic energy emitted by the array of seismic sources;
- and
- d) generating a parameter indicative of a property of the amplitude spectrum of seismic energy emitted by the array of seismic sources.
A method of seismic surveying using one or more marine vibrators, the method comprising:
- emitting seismic energy at two or more different depths during a sweep;
- and
- varying the depth of a marine vibrator while the marine vibrator is emitting seismic energy.
A seismic surveying arrangement comprising:
- a vessel;
- a marine vibrator;
- means for suspending the marine vibrator from the vessel;
- a first control means for causing the marine vibrator to emit seismic energy;
- and
- a second control means for varying the depth of the marine vibrator as it emits the seismic energy.
Dependencies are inferred from the claim text.