Pgs Geophysical As

Saudi Arabian Oil Company

Rolf Huibert Baardman

Roald Gunnar Van Borselen

Christian Wilhelm Strand

Robertus Franciscus Hegge

Manuel Beitz

Steven Fishburn

Alan Ryder

Rob Franciscus Hegge

Gert-Jan Adriaan Van Groenestijn

Martijn O Frijlink

Seismic data are obtained by recording simultaneously in seismic streamer, 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 residuals 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.

Method and system for separating seismic sources in marine simultaneous shooting acquisition

Systems and computer readable media are described that actuate at least one marine seismic source according to a constrained sequence. The sequence exhibits an actuation time or distance interval between each actuation. The actuation time or distance interval corresponds to the sum of a nominal time or distance and a respective dither time or dither distance for each actuation. The sequence is constrained such that differences between consecutive dither times or dither distances remain within a threshold dither difference. Constraining the sequence according to the threshold dither difference enables increased bottom speeds for the source (i.e., increased speeds of the source relative to the seafloor), while still maintaining at least a minimum actuation time or distance interval for the source, taking into account both the nominal time or distance and the respective dither times or dither differences.

Constraint of dithering of source actuations

Systems and methods include a method for deblending signal and noise data. A shot domain for actual sources, a receiver domain for virtual sources, and a receiver domain for actual sources are generated from blended shot data. A dictionary of signal atoms is generated. Each signal atom includes a small patch of seismic signal data gathered during a small time window using multiple neighboring traces. A dictionary of noise atoms is generated. Each noise atom includes a small patch of seismic noise data gathered during a small time window using multiple neighboring traces. A combined signal-and-noise dictionary is generated that contains the signal atoms and the noise atoms. A sparse reconstruction of receiver domain data is created from the combined signal-and-noise dictionary. The sparse reconstruction is split into deblended data and blending noise data based on atom usage to create deblended shot domain gathers for actual sources.

Deblending using dictionary learning with virtual shots

Computational systems and methods for randomizing the order in which multiple sources are fired in simultaneous source acquisition are described. In one aspect, pseudo-randomly shifted time delays are generated for each shot interval of a marine-survey-time line. Each shifted time delay is assigned to one or the sources. The sources within each shot interval are fired based on the shifted time delays.

Systems and methods for randomizing firing times of simultaneous sources in marine surveys

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for training a seismic data de-blending model. In one aspect, a method comprises: obtaining a plurality of de-blending training examples, wherein each de-blending training example defines: (i) one or more blended seismic traces, and (ii) for each blended seismic trace, a corresponding plurality of target unblended seismic traces; using the de-blending training examples to train a de-blending model having a plurality of de-blending model parameters, comprising, for each de-blending training example: processing the one or more blended seismic traces of the training example using the de-blending model to generate an output which defines, for each of the one or more blended seismic traces of the training example, a corresponding plurality of estimated unblended seismic traces; and adjusting values of the plurality of de-blending model parameters.

Seismic data de-blending

This disclosure presents methods and systems for deblending blended seismic data obtained during simultaneous shooting acquisition into deblended seismic data gathers. Methods and systems iteratively separate the blended seismic data into the deblended seismic data gathers based on semblance analysis of a residual difference between the blended seismic data and the deblended seismic data gathers. Each deblended seismic data gather is associated with one of the sources and appears to have been obtained without substantial interference from seismic energy produced by other sources.

Methods and systems for quantifying coherency and constraining coherency-based separation in simultaneous shooting acquisition

The present disclosure is related to methods, systems, and machine-readable media for interference attenuation of a residual portion of seismic data, such as may be recorded in a marine seismic survey. Recorded seismic data can be separated into a portion attributed to a source and a residual portion. Seismic interference attenuation can be performed on the residual portion.

Interference attenuation of a residual portion of seismic data

A system for constraining a dither time can comprise a source and a controller coupled to the source. The controller can be configured to actuate the source in sequence, while the source is moving through a fluid volume at a bottom speed, with an actuation time interval between each actuation comprising a sum of a nominal time and a dither time for each actuation and constrain the dither time for each actuation such that a reduction of the actuation time interval relative to a directly precedent actuation time interval is at most a threshold dither time difference, wherein the threshold dither time difference corresponds to a maximum bottom speed.

A method for estimation of water properties from seismic data can include determining a number of travel times for at least one event based, at least in part, on predefined values for a plurality of water properties, determining an alignment of data values for each of the number of travel times determined for the at least one event, and determining an estimation of a plurality of undetermined water property values based, at least in part, on the alignment of the data values for each of the number of travel times producing a high quantitative measure of a coherence value.

Estimation of water properties from seismic data

Artefacts arising from imperfect extrapolation of a data set subjected to filtering operation are removed by forming a model of the extrapolated data, performing a filtering process on the model and the data set to form a filtered model and a filtered data set, and adaptively subtracting the filtered model from the filtered data set. The adaptive subtraction may employ a least-square error filter.

Method of suppressing spectral artefacts of wavefield decomposition caused by imperfect extrapolation

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.

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Leiden, Netherlands

Rolf Huibert Baardman