Raw 3D seismic streamer wavefield data is received as a receiver-ghosted shot gather. The received receiver-ghosted shot gather shot gather is processed into a normalized form as normalized data. The normalized data is partitioned into a plurality of user-defined sub-gathers and processed to generate a complete receiver-deghosted shot gather. Output of the complete receiver-deghosted shot gather is initiated.

Computing device, computer instructions and method for processing energy at a free-surface reflection relating to an air-water interface. The method includes receiving input seismic data recorded with seismic sensors; receiving wave-height data that describes an actual shape of a top surface of a body of water; processing up-going energy at a receiver and down-going energy following a reflection at the sea-surface, using the input seismic data and a linear operator modified to take into account the wave-height data; and generating an image of the subsurface based on the up-going energy or the down-going energy or a combination of the input seismic data and one of the up-going or down-going energy.

Synthetic survey data is generated using a two-way or one-way wave propagator based on a current model of a target structure. The current model is modified to reduce a difference between the synthetic survey data and observed survey data, while maintaining unchanged a velocity component of the current model, where the modifying of the current model produces a modified model. The modified model is used to reduce an adverse effect of multiples in the target structure, or to promote a favorable effect of multiples in the target structure.

Embodiments of dynamic gain adjustments in seismic surveys are described. One method of acquiring a seismic survey includes determining an arrival time at a seismic receiver of a downgoing seismic wavefield associated with a seismic source based at least in part on an estimated position of the seismic source, an estimated position of the seismic receiver, or combinations thereof. The method also includes adjusting a gain of the seismic receiver based at least in part on the determined arrival time of the downgoing seismic wavefield in order to, for example, help prevent overdriving or clipping of the seismic receiver when the downgoing seismic wavefield arrives at or passes by the seismic receiver.

Systems, methods, and computer-readable media for estimating a component of a seismic wavefield. The method may include accessing marine seismic data comprising a plurality of discrete measurements of a seismic wavefield; processing the marine seismic data to determine a relationship between a plurality of components of the seismic wavefield and each of the discrete measurements; and estimating from the marine seismic data processed via the one or more processors, each component of the seismic wavefield separated from each of the other plurality of components of the seismic wavefield and evaluated at a predetermined position.

A method includes receiving, via a processor, input data based upon received seismic data, migrating, via the processor, the input data via a pre-stack depth migration technique to generate migrated input data, encoding, via the processor, the input data via an encoding function as a migration attribute to generate encoded input data having a migration function that is non-monotonic versus an attribute related to the input data, migrating, via the processor, the encoded input data via the pre-stack depth migration technique to generate migrated encoded input data, and generating an estimated common image gather based upon the migrated input data and the migrated encoded input data. The method also includes generating a seismic image utilizing the estimated common image gather, wherein the seismic image represents hydrocarbons in a subsurface region of the Earth or subsurface drilling hazards.

A method for deghosting marine seismic streamer data includes receiving the marine seismic data recorded from a single streamer. A representation of an upgoing wavefield in the marine seismic data is defined. The representation of the upgoing wavefield includes a first wave component in a plane and a second wave component that is perpendicular to the plane. A linear system is built that models a wavefield using the representation. The wavefield includes the upgoing wavefield and a downgoing ghost wavefield. The upgoing wavefield is estimated, within the representation, by inverting the linear system.

Computing device, computer instructions and method for correcting an image, of a surveyed surface, due to a free-surface reflection. The method includes calculating a free surface reflection operator for a seismic source displaced in water based on a position of the source, and an air-water interface datum; receiving recorded seismic data d recorded with seismic sensors (r), wherein the recorded seismic data is associated with a pressure and/or a particle motion produced by a seismic wave in earth; correcting the recorded seismic data d based on the free surface reflection operator to obtain transformed seismic data; and generating an image of the surveyed subsurface, based on the transformed seismic data, wherein the image is indicative of various layers of the earth. The free surface reflection operator varies while a source signal is being emitted by the source.

Systems and methods for attenuating multiples in seismic data are presented. In one aspect, predicted surface-related multiples are calculated for seismic data generated by receivers in a marine survey. Estimates of primaries and multiples may be calculated by applying adaptive subtraction to the predicted surface-related multiples. Residual multiples present in the estimated primaries may be identified using multiple diffraction reduction. The residual multiples and estimated multiples are used to generate final estimated multiples that are subtracted from the seismic data to generate primaries with attenuated multiples.

Methods and systems for processing data acquired using a variable-depth streamer, obtain up-going and down-going wavefields at a predetermined datum, and use them to identify multiples included in the up-going wavefield. An image of a geological formation under the seabed is then generated using the data from which the multiples have been removed, and/or the multiples.