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: Methods and systems for determining and removing swell noise from electric field data collected from streamers towed at different are disclosed. In one aspect, a first set of streamers called upper streamers is towed at a shallow depth, and the second set of streamers called lower streamers is towed below the upper streamers. Receivers located along the streamers measure surrounding electric fields and produce electric field signals. A proportionality parameter is calculated as a function of the electric field signals generated by vertically aligned receivers. The proportionality parameter can be used to calculate an approximate swell noise that is used to remove swell noise from electric field data measured by the receivers.

Abstract: A sensor event assessor input/output controller is disclosed. In one embodiment, a multi-channel sensor input configuration provides two-way communication with a plurality of sensors, each of the plurality of sensors having its own channel. An electronic signal receiver receives electronic signals from one or more of the plurality of sensors at a pre-defined sample rate. A signal combiner bundles the electronic signals from one or more of the plurality of sensors into a single electronic signal. A single channel output is used to provide the single electronic signal to the sensor event assessor.

Abstract: Presented are methods and systems for deghosting seismic trace data. A cost function and one or more applicable constraints are selected and used to generate a time-variant deghosting filter. The time-variant deghosting filter can be recalculated for predetermined time intervals over the span of the associated seismic data. The time-variant deghosting filter is then applied to the seismic trace data to attenuate ghosts within the predetermined time interval. A plurality of seismic trace data can be stacked before generating and applying the time-variant deghosting filter.

Abstract: A method of attenuating interbed multiples in multiply-reflected seismic waves is performed at a computer system, the method including: providing multiple beams of seismic data and an earth model related to a geological volume; selecting one of the beams as an input beam associated with a pair of source and detector located near a top surface of the geological volume; determining at least one of (i) a source-side stationary pegleg arrival and a corresponding detector-side primary beam and (ii) a detector-side stationary pegleg arrival and a corresponding source-side primary beam; predicting an interbed multiples beam using at least one of (i) the detector-side primary beam delayed by the source-side stationary pegleg arrival and (ii) the source-side primary beam delayed by the detector-side stationary pegleg arrival; and deconvolving the predicted interbed multiples beam with the input beam to remove at least a portion of interbed multiples present in the input beam.

Abstract: A method and apparatus for predicting interbed multiples is described herein. Trace geometries may be generated for one or more desired shot-side traces, one or more desired receiver-side traces, and one or more desired interbed multiple generator traces, for a first target trace. A first set of reflections at the interbed multiple generator layer may be extracted from one or more recorded traces closest to the desired interbed multiple generator traces. A second set of reflections below the interbed multiple generator layer may be extracted from one or more recorded traces closest to the desired shot-side traces. A third set of reflections below the interbed multiple generator layer may be extracted from one or more recorded traces closest to the desired receiver-side traces. The interbed multiples for the first target trace may be estimated based on the first set, the second set, and the third set.

Abstract: Computational methods and systems for deghosting marine seismic streamer data are described. In particular, an exploration-seismology vessel tows a number of streamers that form a data acquisition surface located beneath a free surface. The methods computationally deghost or substantially remove receiver ghost signals from seismic data recorded by steamer receivers. The deghosting methods include low frequency compensation to recover vertical velocity wavefield information that is typically lost due to a low signal-to-noise ratio over a low frequency range independent of the free surface conditions or the shape of the data acquisition surface.

Abstract: Computing device, computer instructions and method for de-ghosting seismic data related to a subsurface. The method may include receiving input seismic data recorded by seismic receivers that located at different depths (zr), generating migration data (du) and mirror migration data (dd) from the input seismic data, deriving a ghost free model (m) based on simultaneously using the migration data (du) and mirror migration data (dd), generating primary (p) and ghost (g) datasets based on the ghost free model (m), simultaneously adaptively subtracting the primary (p) and ghost (g) datasets from the migration data (du) to provide adapted primary (p?1 and p?2) and adapted residual (r?1 and r?2) datasets, and generating a final image (f) of the subsurface based on the adapted primary (p?1 and p?2) and the adapted residual (r?1 and r?2) datasets. In certain embodiments, the input seismic data d includes both hydrophone data and particle motion data.

Abstract: Methods, apparatuses, and systems are disclosed for datuming multi-component seismic data. In one example of such a method, a plurality of seismic traces are accessed, the plurality of seismic traces including data representative of amplitude and spatial gradient samples of a seismic wavefield at a plurality of recording locations in a medium. Using a computer-based processing unit, a wavefield propagation from the plurality of recording locations through a medium is initialized, using the amplitude and spatial gradient samples of the seismic wavefield. Seismic traces are generated that correspond to the propagated wavefield at defined locations within the medium.

Abstract: Computing device, computer instructions and method for directional designature of seismic data d with a given source directivity. The method includes obtaining directional operators r; calculating a model u with a modified source directivity based on (1) seismic data d, and (2) an operator that is a combination of the directional operators r and a reverse transform operator L; using the model u to obtain seismic data dfree with modified source directivity; and generating a final image of the subsurface using seismic data dfree.

Abstract: One embodiment relates to a method for deghosting seismic data from a marine seismic survey. The seismic data from the marine seismic survey is obtained, where the marine seismic survey was performed using multiple sub-sources towed at two or more different depths and fired at distinct time-delays. The seismic data is sorted into common receiver gathers, and the common receiver gathers are transformed from horizontal source coordinates to horizontal wavenumbers. For each selected frequency, a matrix operator is constructed, and an inversion procedure is applied to a system of equations based on the matrix operator to generate source-deghosted seismic data. Other embodiments, aspects and features are also disclosed.

Abstract: Propagation of wavefields are simulated along paths in a survey environment, where the simulated propagation includes an influence of a reflection at an interface that causes ghost data in measured survey data. Deghosting of the measured survey data is performed using the simulated wavefields.

Abstract: Methods, devices, and computer-readable media are provided for accessing seismic data that describes seismic energy that propagated through media, including water and optionally surface or subsurface layers, to measurement locations in the water. The seismic data includes pressure data that describes time-variant pressures at measurement locations in the water. The seismic data may also include velocity data that describes time-variant velocities of particles at measurement locations in the water. The seismic data is processed using wavefield decomposition to reduce an effect of a portion of the seismic energy that reflects off of the surface of the water. The processing is performed in a discrete domain that includes or is the measurement locations. The discrete domain may exclude certain locations or ranges of locations. The processed seismic data may be used to generate a map of any surfaces of the media through which the seismic energy propagated.

Abstract: A method for deghosting seismic data collected with a seismic system, the seismic data being related to a subsurface of a body of water. The method includes receiving the seismic data recorded by detectors distributed along a variable-depth profile; calculating migrated (d1) and mirror-migrated (d2) gathers based on the seismic data, wherein the migrated and mirror-migrated gathers depend on a feature characterizing a configuration of the seismic system; applying a joint deconvolution model to the migrated and mirror-migrated gathers (d1, d2) to calculate a single deghosted gather (dg); and generating a final image of the subsurface based on the single deghosted gather (dg). The feature is not present in a gather after a step of stacking that is performed prior to generating the final image.

Abstract: Systems and methods for imaging subterranean formations using primary and multiple reflections are described. An exploration-seismology vessel tows a seismic source, a receiver acquisition surface located beneath a free surface, and a source acquisition surface positioned at a depth below the source. The receiver acquisition surface is used to measure pressure and normal velocity wavefields and the source acquisition surface is used to measure direct, down-going, source pressure wavefields generated by the source. The down-going source pressure wavefields in combination with the down-going pressure wavefields and up-going pressure wavefields computed from the pressure and velocity wavefields are used to compute images of the subterranean formation associated with primary reflections and multiple reflections.

Abstract: Rough sea elevation is estimated from a high-frequency portion of recorded pressure data and recorded vertical velocity component data. Generalized deghosting and datuming operators are constructed, which take into account the estimated rough sea elevation and irregular recording depth conditions. A low-frequency portion of the recorded pressure data is decomposed into up-going and down-going wavefields on a horizontal reference plane, using the generalized datuming and deghosting operators. A low-frequency portion of the vertical velocity component data is reconstructed from the decomposed up-going and down-going wavefields on the horizontal reference plane, using the generalized datuming and deghosting operators.

Abstract: A technique includes acquiring particle motion data from a plurality of particle motion sensors while in tow during a seismic survey. During the seismic survey, the particle motion data are processed without deghosting the particle motion data to determine whether at least some portion of the particle motion data is inadequate for an application that relies on the particle motion data.

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 technique includes receiving first data indicative of a pressure measurement and measurements of components of a particle motion vector acquired by sensors disposed on at least one cable; and processing the first data to generate second data indicative of a constructed an in-line component of the particle motion vector. The technique includes processing the first and second data in a geophysical processing operation that relies on at least three components of the particle motion vector.

Abstract: Method for representing seismic data as a spatially varying, second-order tensor field (23). The spatial relationships expressed in these tensors are exploited to link, classify, or separate neighborhoods (22); or to infer global or relational properties among them, thereby suggesting geobodies despite a noisy background. The tensors may be decomposed into their fundamentals that may either be used directly as derivative datasets or attributes, or may be used to facilitate linkage, classification, or separation of neighborhoods or analysis of linkage patterns. Decomposition may be by eigenvalues, with the eigenvalues used to define attributes called ballness, plateness and stickness (24). Alternatively, connections may be made between points in the data where the tensor has been computed, called tokens (21), based on tensor voting and polarity. Or, the connections may be based on a distance measure between tokens.

Abstract: Embodiments of the invention provide a method of processing marine seismic data, the data having been acquired using a “dense over/sparse under” streamer array having N over streamers disposed at a first depth and M under streamers disposed at a second depth greater than the first depth, where 0<M<N. The method comprises: a) processing seismic data for one of the over streamer target locations and seismic data for one of the under streamer target locations; b) processing seismic data for another of the over streamer target locations; and c) combining the result of (a) and the result of (b). The one of the over streamer target locations and the one of the under streamer target locations may lie in a vertical plane.

Abstract: Seismic data are obtained by recording simultaneously in seismic streamers, acquired by activating approximately simultaneously two or more seismic sources towed at two positions in the vicinity of seismic streamers. A residual is updated iteratively for an inversion solution for the activations of the two or more seismic sources. The iterative updating of the residual utilizes a sequence of overlapping temporal windows containing reflection events and utilizes normal moveout corrections based on largest reflection events in each temporal window. A final updated residual is added to a final updated model result.

Abstract: A technique includes representing actual measurements of a seismic wavefield as combinations of an upgoing component of the seismic wavefield and ghost operators. Interpolated and deghosted components of the seismic wavefield are jointly determined based at least in part on the actual measurements and the representation.

Abstract: Seismic data recorded in a marine streamer are obtained, sorted as a common receiver gather. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a source deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide source deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: Measurement data is received from first and second seismic sensors, where the first and second seismic sensors are oriented in opposite directions. Each of the first and second seismic sensors has a sensing element responsive to pressure and particle motion. The signals can be combined to remove the particle motion component of the measurement data and obtain pressure-only data. Alternatively, the signals can be combined to deghost the received measurement data.

Abstract: A device for collecting samples of the sea floor, including a collection apparatus, a diving apparatus and a control apparatus.

Abstract: Computing device, computer instructions and method for simultaneously denoizing and attenuating multiples in seismic data recorded with seismic receivers. The method includes receiving the seismic data, wherein the seismic data includes a pressure P component and a vertical Z component; separating the seismic data into up-going U wave-fields and down-going D wave-fields; calculating an up-down deconvolution R based on the up-going U and the down-going D wave-fields; generating a multiple model M based on the up-down deconvolution R; and adaptively subtracting the multiple model M from the pressure P component to obtain a corrected pressure Pfree component from which simultaneously the noise and the multiples were removed. A multiple is a wave-field that propagates from a source to a receiver and experiences more than one reflection.

Abstract: A seismic streamer system for acquiring seismic data includes a plurality of first cable sections each employing a first sensor configuration therein, and at least one second cable section operatively connected to one or more of the first cable sections and employing a second sensor configuration therein. In various embodiments of the streamer system, one or more of the second cable sections are sparsely integrated into a streamer, a streamer array and/or a seismic spread. The first sensor configuration may, e.g., include a conventional hydrophone distribution, and the second sensor configuration may, e.g., include multicomponent sensors such as at least one of a particle velocity sensor, a pressure gradient sensor, an accelerometer and a combination thereof. The present invention is useful for attenuating noise in the measured seismic data as well as deghosting the data.

Abstract: Device and method for processing 4-dimensional (4-D) seismic traces. The method includes receiving at least two vintages of seismic traces recorded by seismic receivers for a same subsurface area, wherein said seismic receivers are located at the ocean floor; applying up-down deconvolution to each of said vintages of seismic traces to obtain a representation of a reflectivity of said subsurface area from each vintage of seismic traces; and redatuming the up-down deconvolution result of each vintage from the ocean floor to a desired water depth of the ocean to reduce one or more changes in said seismic traces associated with water layer variations between recordings of said series of seismic traces. The redatumed seismic data is used to generate one or more images representing characteristics of said subsurface area.

Abstract: Apparatus, computer instructions and method for combining first and second records to form a substantially deghosted seismic record.

Abstract: A method of marine time-lapse seismic surveying of a subsurface formation, comprises providing a baseline survey, providing a monitor survey that includes information about changes in the subsurface relative to the baseline survey, recording a repeat survey so closely in time to one of either the baseline survey or the monitor survey that changes in the subsurface can be ignored but under different near-surface conditions from said one survey, computing a short-time survey difference between the repeat signals and signals comprising said one of either the baseline survey or the monitor survey, computing a monitor survey difference, matching the short-time survey difference and the monitor survey difference to derive a matched noise survey difference, subtracting the matched noise survey difference from the monitor survey difference, and outputting a noise suppressed survey difference based on the result of the subtraction.

Abstract: A system and a method for rejecting noise in an underwater sensor cable, such as a towed streamer or an ocean-bottom cable. An adaptive hydrodynamic model of the cable produces an estimated sensor signal from a raw sensor signal from a particle-motion sensor, such as an accelerometer. The estimated sensor signal represents an estimate of the response of the underwater cable to cable motion absent seismic events. A noise-reduced response to particle motion alone is produced by subtracting the estimated sensor signal from the raw sensor signal to reject cable motion and other noise effects in the raw sensor signal. A seismic event detector uses a hydrophone signal from an acceleration-canceling hydrophone to disable the adapting of the hydrodynamic model during seismic events. The hydrophone signal is combined with the response to particle motion by PZ summation to produce a deghosted seismic response signal.

Abstract: A technique includes spatially filtering a signal that is derived from a seismic acquisition. The filtering is associated with a filter length, and the filtering includes varying the filter length with frequency. The filtering may be used in connection with adaptive noise attenuation, which is applied to decomposed subbands. Furthermore, the filtering may be applied during the reconstruction of the signal from the subbands.

Abstract: A method and apparatus for predicting a plurality of surface multiples for a plurality of traces in a record of seismic data. In one embodiment, the method includes providing a plurality of target traces at a nominal offset and a nominal azimuth; selecting a plurality of pairs of input traces, wherein the midpoints of the input traces in each pair are separated by half the nominal offset and the azimuth of a line connecting the midpoints of the input traces in each pair is equal to the nominal azimuth; convolving the selected pairs of input traces to generate a plurality of convolutions; and applying a three dimensional operator to the convolutions.

Abstract: In response to at least one input criterion, one or more target positions in an acquisition domain are determined for processing of survey data, where the survey data is acquired by survey equipment in the acquisition domain having a first set of dimensions, and where the processing of the survey data is to be performed in a processing domain having a second set of dimensions different from the first set of dimensions.

Abstract: Systems and methods are provided for processing seismic data and displaying an output associated with the seismic data. A method includes: separating the seismic data into a fine-scale dataset and a coarse-scale dataset, wherein each dataset includes a non-zero portion of the data; applying a first interpolation to the coarse-scale dataset which results in an interpolated coarse-scale dataset; applying a second interpolation to the fine-scale dataset which results in an interpolated fine-scale dataset, wherein the first and second interpolation are different interpolations; summing together the interpolated coarse-scale dataset and the interpolated fine-scale dataset which results in a summed interpolated dataset; and displaying at least one image based on the summed interpolated dataset.

Abstract: A method for modeling shallow water multiples modeling using a predicted sea floor reconstruction is provided. A seafloor reflectivity image is reconstructed using acquired seismic data. Surface multiples are determined by evaluating a seismic wave equation using, as an input, the reconstructed seafloor reflectivity image. The determined surface multiples are subtracted from the acquired seismic data.

Abstract: A technique includes receiving first data acquired by at least a particle motion gradient sensor or a rotation sensor of a streamer that is subject to vibration due to towing of the streamer; and receiving second data acquired by at least one particle motion sensor of the streamer and being indicative of particle motion and vibration noise. The technique includes processing the second data in a processor-based machine to, based at least in part on the first data, attenuate the vibration noise indicated by the second data to generate third data indicative of the particle motion.

Abstract: Systems and methods for operating a seismic source to attenuate shot generated noise, or residual energy from previous activation of the source, in recorded seismic data are described. In one aspect, methods operate a single seismic source towed through a body of water along a survey track. As the survey vessel travels along the survey track, the source is activated at the end of randomly selected time delays, resulting in attenuation of shot generated noise. The method also attenuates other forms of coherent noise that align from shot to shot.

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: The maximum output of a seismic source array may be reduced by activating the individual seismic sources within these seismic source array in a pattern that is extended in time rather than by the presently employed conventional simultaneous activation of a large number of individual seismic sources. Methods are disclosed which take data shot with patterned sources and may use a sparse inversion method to create data with the about same image quality as that of conventional sources. In this manner the output of the maximum impulse of a seismic source array may be reduced by an amplitude factor of about 10 in the examples shown here, corresponding to a reduction of about 20 dB while maintaining virtually the same seismic image quality. The disclosed methods may be used in combination with any simultaneous sourcing technique. In addition, the disclosed methods may be used with a plurality of source arrays.

Abstract: Provided is an apparatus of imaging a subsurface of a target area. The apparatus includes: an observed wavefield acquiring unit configured to acquire an observed wavefield for a target area based on seismic data; a parameter storage configured to store a characteristic parameter for the target area; a modeled wavefield creator configured to create a modeled wavefield corresponding to the observed wavefield using the characteristic parameter stored in the parameter storage; an energy calculator configured to calculate accumulated energies of the observed wavefield and the modeled wavefield, wherein the accumulated energies are defined as energies accumulated over time with respect to the observed wavefield and the modeled wavefield; and a parameter updating unit configured to update the characteristic parameter stored in the parameter storage such that a difference between the accumulated energy of the observed wavefield and the accumulated energy of the modeled wavefield is minimized.

Abstract: Methods, apparatuses, and systems are disclosed for datuming multi-component seismic data. In one example of such a method, a plurality of seismic traces are accessed, the plurality of seismic traces including data representative of amplitude and spatial gradient samples of a seismic wavefield at a plurality of recording locations in a medium. Using a computer-based processing unit, a wavefield propagation from the plurality of recording locations through a medium is initialized, using the amplitude and spatial gradient samples of the seismic wavefield. Seismic traces are generated that correspond to the propagated wavefield at defined locations within the medium.

Abstract: A merged particle velocity signal is generated by merging a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by velocity analysis, with a simulated particle velocity signal, calculated in a lower frequency range from a recorded pressure signal using a time-varying filter based on the time-dependent arrival time. Combined pressure and vertical particle velocity signals are generated by combining the recorded pressure and merged velocity signals.

Abstract: Systems and methods for detecting swell noise in geophysical data are disclosed. In particular, the systems and methods receive seismic data as input and iteratively generate a signal mask from the seismic data. The seismic data can be generated by hydrophones or geophones. The signal mask can be used to identify traces in the seismic data that are contaminated with swell noise and identify frequencies of the contaminated traces that are contaminated with swell noise.

Abstract: A system and method are provided for determining shallow water multiples when seismically exploring a geographical area of interest under a body of water. The system and method estimate a multi-channel prediction operator F using a model of water layer related multiples with respect to received and stored seismic data, estimate a travel time of the transmitted seismic wavelets from the one or more sources to each of the plurality of receivers, and then generate water layer primary reflections models using the estimated travel time and Green's function. The system and method then merge the generated water layer primary reflections models with the multi-channel prediction operator F to create a hybrid multi-channel prediction operator FH, and convolute the hybrid multi-channel prediction operator FH with the stored received data to determine a final multiples model.

Abstract: Methods and systems for ghost compensation which are embedded in beam migration are described. The ghost compensation is based on the fact that the beam migration is performed in the slant-stack domain. The trace data is transformed to a mid-point slant-stack frequency domain where a deghosting operator is applied and then the deghosted trace data is inverse transformed to a time domain. The time domain trace data can then be further processed as desired.

Abstract: A method for processing seismic data related to a structure under a body of water to generate an image of the structure includes receiving seismic data acquired using detectors disposed on a depth-varying profile streamer. The method further includes generating, from the seismic data, first traces that correspond to traces as recorded by the detectors and migrated to water surface, and second traces that correspond to traces as would be recorded by virtual detectors mirroring the detectors relative to the water surface and migrated to water surface. The method also includes generating third traces as a sum of corresponding ones among the first traces and second traces, and fourth traces as a difference of the corresponding ones of the first and second traces. The method then includes deghosting at least one of the first and second traces using positive and negative polarity portions of the third and fourth traces.

Abstract: Methods and systems for determining and removing swell noise from electric field data collected from streamers towed at different are disclosed. In one aspect, a first set of streamers called upper streamers is towed at a shallow depth, and the second set of streamers called lower streamers is towed below the upper streamers. Receivers located along the streamers measure surrounding electric fields and produce electric field signals. A proportionality parameter is calculated as a function of the electric field signals generated by vertically aligned receivers. The proportionality parameter can be used to calculate an approximate swell noise that is used to remove swell noise from electric field data measured by the receivers.

Abstract: Propagation of wavefields are simulated along paths in a survey environment, where the simulated propagation includes an influence of a reflection at an interface that causes ghost data in measured survey data. Deghosting of the measured survey data is performed using the simulated wavefields.