Abstract: Source element of a source subarray can be individually actuated according to an actuation sequence. The actuation sequence can be at least partially based on a relative position of each of the source elements within a particular geometry of the source subarray with respect to a previously actuated source element and a towing velocity of the source subarray.

Abstract: At least some embodiments are directed to a system. The system includes a processor and a memory coupled to the processor. The memory stores a program that, when executed by the processor, causes the processor to calculate a pressure response of a first sensor, and correct pressure wavefield data obtained from the first sensor responsive to a first acoustic wavefield. The correction is based on the calculated pressure response of the first sensor. The pressure response of the first sensor is responsive to a second acoustic wavefield having a propagation path between a source of the second acoustic wavefield and the first sensor, in which the propagation path includes no reflection from a subsurface formation.

Abstract: This disclosure is directed to systems and methods of wavefield separation based on matching operators that represents the relationship between co-located pressure and particle motions sensors. A pressure wavefield and a particle motion wavefield emitted from a subterranean formation are measured using co-located pressure and particle motion sensors located along one or more streamers of a seismic data acquisition system. A matching operator that relates pressure sensor and particle motion sensor responses for co-located pressure and particle motion sensors is computed based on depth of the co-located pressure and particle motion sensors and on the measured pressure and particle motion wavefields. The matching operator and the measured pressure and particle motion wavefields may then be used to compute up-going and down-going wavefields.

Abstract: A data set representing features of a geologic formation is formed from two or more signal acquisition data set representing independent aspects of the same wavefield. A wavelet transform is performed on the two or more signal acquisition data sets, and the data sets are further transformed to equalize signal portions of the data sets. Remaining differences in the data sets are interpreted as excess noise and are removed by different methods to improve the signal-to-noise ratio of any resulting data set.

Abstract: Computational systems and methods that combine global frequency-wavenumber-domain (“f-k domain”) filters with localized eigenimage based event selection to generate a resulting wavefield with reduced filter imprints on gather edges, reduced noise, and correct treatment of aliased energy are disclosed. The methods are executed by applying filters to the full set of seismic gather data in the f-k domain in order to obtain a resulting wavefield from recorded pressure and/or particle velocity data. The output of the filter is iteratively decomposed according to local dip values using eigenimage processing based on singular value decomposition (“SVD”). The same sample locations are extracted using SVD from the input in addition to generating input for a subsequent iteration with already processed data removed. Eigenimage processing methods allow for correct treatment of spatially aliased energy in f-k domain filtering.

Abstract: Filters are applied to seismic signals representative of subsurface formations to generate filtered signals with attenuated spatially aliased energy. The filtered signals are multiplied in the frequency-wavenumber domain by a complex function of frequency and wavenumber representing the seismic attribute in the frequency-wavenumber domain, to generate scaled signals. The scaled signals, transformed to the time-space domain, are divided by the filtered signals in the time-space domain, to a seismic attribute useful for identifying and characterizing the subsurface formations.

Abstract: A cross-line slowness is determined for each sample in the signals in towed marine seismic streamers. A range of assumed cross-line slownesses is selected. Vertical wavenumbers are determined using the range of assumed cross-line slowness determined for samples in the signals of pressure sensors and particle motion sensors in the towed marine seismic streamers. The determined vertical wavenumbers are used to correct the particle motion sensor signals for angle of incidence along the direction of the seismic streamers and transverse thereto to generate a corrected particle motion sensor signal. The corrected particle motion sensor signals are combined based on the determined cross-line slowness for the samples. The corrected particle motion sensor signal and the pressure sensor signal are used to determine at least one of upgoing and downgoing pressure components and upgoing and downgoing particle motion components of the particle motion sensor and pressure sensor seismic signals.

Abstract: A first weighted integral operator is applied to dual-sensor data to extrapolate the dual-sensor data to a first position above an acquisition surface, generating extrapolated data. A second weighted integral operator is applied to the extrapolated data to extrapolate the extrapolated data to a second position, generating wavefield separated data. One of the integral operators is applied to a scaled combination of the dual sensor data.

Abstract: A method for determining upgoing pressure components of seismic signals from signals detected by combined pressure responsive sensors and motion responsive seismic sensors disposed in a plurality of laterally spaced apart streamers includes determining a threshold time at which angle of incidence error in the motion responsive signals in the cross-line direction falls below a selected threshold. Below the threshold time, the motion responsive signals are corrected for angle of incidence in the in-line and cross-line directions. Above the threshold time, the motion responsive signals are corrected for angle of incidence only in the in-line direction. Both sets of incidence corrected measured motion responsive signals, and the pressure responsive signals are used to determine upgoing or downgoing pressure components or upgoing or downgoing motion components of the measured motion responsive and pressure responsive seismic signals.

Abstract: A cross-line slowness is determined for each sample in the signals in towed marine seismic streamers. A range of assumed cross-line slownesses is selected. Vertical wavenumbers are determined using the range of assumed cross-line slowness determined for samples in the signals of pressure sensors and particle motion sensors in the towed marine seismic streamers. The determined vertical wavenumbers are used to correct the particle motion sensor signals for angle of incidence along the direction of the seismic streamers and transverse thereto to generate a corrected particle motion sensor signal. The corrected particle motion sensor signals are combined based on the determined cross-line slowness for the samples. The corrected particle motion sensor signal and the pressure sensor signal are used to determine at least one of upgoing and downgoing pressure components and upgoing and downgoing particle motion components of the particle motion sensor and pressure sensor seismic signals.

Abstract: Filters are applied to seismic signals representative of subsurface formations to generate filtered signals with attenuated spatially aliased energy. The filtered signals are multiplied in the frequency-wavenumber domain by a complex function of frequency and wavenumber representing the seismic attribute in the frequency-wavenumber domain, to generate scaled signals. The scaled signals, transformed to the time-space domain, are divided by the filtered signals in the time-space domain, to a seismic attribute useful for identifying and characterizing the subsurface formations.

Abstract: A first weighted integral operator is applied to dual-sensor data to extrapolate the dual-sensor data to a first position above an acquisition surface, generating extrapolated data. A second weighted integral operator is applied to the extrapolated data to extrapolate the extrapolated data to a second position, generating wavefield separated data. One of the integral operators is applied to a scaled combination of the dual sensor data.

Abstract: A method for determining upgoing pressure components of seismic signals from signals detected by combined pressure responsive sensors and motion responsive seismic sensors disposed in a plurality of laterally spaced apart streamers includes determining a threshold time at which angle of incidence error in the motion responsive signals in the cross-line direction falls below a selected threshold. Below the threshold time, the motion responsive signals are corrected for angle of incidence in the in-line and cross-line directions. Above the threshold time, the motion responsive signals are corrected for angle of incidence only in the in-line direction. Both sets of incidence corrected measured motion responsive signals, and the pressure responsive signals are used to determine upgoing or downgoing pressure components or upgoing or downgoing motion components of the measured motion responsive and pressure responsive seismic signals.

Abstract: Pressure records and vertical particle velocity records from dual sensor towed streamer data are transformed to the inline wavenumber domain. A series of scaling filters are applied to the transformed vertical particle velocity records at each inline wavenumber, wherein each of the series of scaling filters is calculated for a different cross-streamer wavenumber range and in blocks of inline traces in which all seismic events are approximately linear. The pressure spectrum and the scaled vertical particle velocity spectrum are combined to separate upgoing and downgoing wavefield components. The separated upgoing and downgoing wavefield components are inverse-transformed back to the time-space domain.

Abstract: Pressure records and vertical particle velocity records from dual sensor towed streamer data are transformed to the inline wavenumber domain. A series of scaling filters are applied to the transformed vertical particle velocity records at each inline wavenumber, wherein each of the series of scaling filters is calculated for a different cross-streamer wavenumber range and in blocks of inline traces in which all seismic events are approximately linear. The pressure spectrum and the scaled vertical particle velocity spectrum are combined to separate upgoing and downgoing wavefield components. The separated upgoing and downgoing wavefield components are inverse-transformed back to the time-space domain.