Abstract: A method for applying separated wave-field imaging onshore (1) by artificially creating up-going and down-going fields and (2) by using these fields in a migration algorithm. If there are any surface multiples in the data, the resulting image created using the migration algorithm will be distorted by the unknown free-surface reflection coefficient. In fact, the surface multiples may be generated with a complex series of reflection coefficients. The distortions found in the resulting image created using the migration algorithm are then removed.

Abstract: A method for applying separated wave-field imaging onshore (1) by artificially creating up-going and down-going fields and (2) by using these fields in a migration algorithm. If there are any surface multiples in the data, the resulting image created using the migration algorithm will be distorted by the unknown free-surface reflection coefficient. In fact, the surface multiples may be generated with a complex series of reflection coefficients. The distortions found in the resulting image created using the migration algorithm are then removed.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors on streamers towed in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold. Other embodiments, aspects and features are also disclosed.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors on streamers towed in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold. Other embodiments, aspects and features are also disclosed.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold. Other embodiments, aspects and features are also disclosed.

Abstract: A method for attenuating noise in marine seismic signals includes cross ghosting pressure responsive marine seismic signals and contemporaneously acquired motion responsive marine seismic signals. A difference is determined between the cross ghosted signals. The difference is used to attenuate noise in at least one of the pressure responsive signals and the motion responsive signals.

Abstract: Techniques are disclosed relating to steering a signal source towed behind a survey vessel. In one embodiment, a method includes towing a signal source and a streamer in a body of water. The signal source includes a steering mechanism. The method further includes determining a current heading of the streamer and, based on the determined heading, using the steering mechanism to adjust a heading of the signal source. In some embodiments, the method also includes determining a current heading of the signal source based on location information received from one or more location buoys coupled to the signal source, and, based on the determined heading of the signal source, using the steering mechanism to adjust the heading of the signal source. In one embodiment, the steering mechanism is used to align the heading of the signal source with the heading of the streamer.

Abstract: A method for towing a marine seismic acquisition array in a body of water includes towing a plurality of laterally spaced apart sensor streamers behind a survey vessel in the water. A lateral spacing between adjacent streamers is represented by L. At least two laterally spaced apart seismic energy sources are towed behind the survey vessel. A lateral spacing between the at least two sources is represented by kL, wherein k is a constant and wherein k is at most equal to the number of streamers.

Abstract: A method for determining quality of signals acquired using marine seismic streamers having pressure responsive sensors and motion responsive sensors includes cross ghosting pressure responsive seismic signals and contemporaneously acquired motion responsive seismic signals. First filters are determined that cause the cross ghosted pressure responsive signals to substantially match the cross ghosted motion responsive signals. Second filters are determined that cause the cross ghosted motion responsive signals to substantially match the cross ghosted pressure responsive signals. The first and second filters are convolved and the convolution is used to determine signal quality.

Abstract: A method for towing a marine seismic acquisition array in a body of water includes towing a plurality of laterally spaced apart sensor streamers behind a survey vessel in the water. A lateral spacing between adjacent streamers is represented by L. At least two laterally spaced apart seismic energy sources are towed behind the survey vessel. A lateral spacing between the at least two sources is represented by kL, wherein k is a constant and wherein k is at most equal to the number of streamers.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold. Other embodiments, aspects and features are also disclosed.

Abstract: A method for operating marine seismic vibrators includes towing at least a first and a second marine seismic vibrator in a body of water beneath the hull of a vessel. At least a third marine seismic vibrator is towed at a selected depth in the water other than beneath the hull of the vessel. The at least first, second and third vibrators are operated to sweep through respective frequency ranges. The first and second frequency ranges have lowermost frequencies and uppermost frequencies respectively differing by a selected sub-harmonic frequency range. The third frequency range has a lowermost frequency at least equal to the uppermost frequency of one of the first and second frequency ranges and traverses a seismic frequency range of interest.

Abstract: A method for operating marine seismic vibrators includes towing at least a first and a second marine seismic vibrator in a body of water beneath the hull of a vessel. At least a third marine seismic vibrator is towed at a selected depth in the water other than beneath the hull of the vessel. The at least first, second and third vibrators are operated to sweep through respective frequency ranges. The first and second frequency ranges have lowermost frequencies and uppermost frequencies respectively differing by a selected sub-harmonic frequency range. The third frequency range has a lowermost frequency at least equal to the uppermost frequency of one of the first and second frequency ranges and traverses a seismic frequency range of interest.

Abstract: A method for determining quality of signals acquired using marine seismic streamers having pressure responsive sensors and motion responsive sensors includes cross ghosting pressure responsive seismic signals and contemporaneously acquired motion responsive seismic signals. First filters are determined that cause the cross ghosted pressure responsive signals to substantially match the cross ghosted motion responsive signals. Second filters are determined that cause the cross ghosted motion responsive signals to substantially match the cross ghosted pressure responsive signals. The first and second filters are convolved and the convolution is used to determine signal quality.

Abstract: A method for estimating formation quality factor includes determining an upgoing pressure wavefield of seismic signals recorded using a collocated pressure responsive sensor and motion responsive sensor deployed in a body of water The upgoing wavefield has spectral effect of water surface ghosting attenuated by combining the pressure responsive signals and motion responsive signals. The quality factor is determined by determining a difference in amplitude spectra between a first seismic event and a second seismic event in the upgoing pressure wavefield.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold.

Abstract: A method for attenuating noise in marine seismic signals includes cross ghosting pressure responsive marine seismic signals and contemporaneously acquired motion responsive marine seismic signals. A difference is determined between the cross ghosted signals. The difference is used to attenuate noise in at least one of the pressure responsive signals and the motion responsive signals.