A method for directional Q compensation of seismic data may comprise calculating angle-dependent subsurface travel times; applying directional Q compensation to the prestack seismic data to obtain Q-compensated data in time-space domain, wherein the directional Q compensation is based on the angle-dependent subsurface travel times; and using the Q-compensated data to generate an image of the subsurface. Directional Q compensation may comprise determining an angle-dependent forward E operator and an angle-dependent adjoint E* operator using the angle-dependent subsurface travel times; and applying a sparse inversion algorithm using the angle-dependent operators to obtain a model of Q-compensated data. The angle-dependent operators may be preconditioned by introducing ghost and source effects in a wavelet matrix and a transpose of the wavelet matrix, respectively, such that applying a sparse inversion algorithm using the preconditioned angle-dependent operators is used to obtain a model of Q-compensated, deghosted data without source effects.

A method and a system for implementing the method are disclosed wherein the pre-stack seismic input data, an initial anellipticity anisotropy parameter, and a baseline normal moveout velocity from a non-flat surface, are sometimes mild or foothill topography as well as the shot and receiver lines might not necessarily be straight, and often curve to avoid obstacles on the land surface. In particular, the method and system disclosed, allows for updating the anisotropy parameters iteratively and when the stopping criteria is satisfied, the final estimated parameter can be directly used for time migration. This method and system are mainly used for time migration with the purpose of obtaining the high fidelity (accurate amplitude, i.e. not only travel-time correct but also amplitude correct) image gathers which are used for reservoir characterization and interpretation.

A zero-offset wavefield synthesis workflow to calculate a synthesized zero-offset wavefield output without the commitment to an rms velocity field output to circumvent velocity uncertainty. Said zero-offset wavefield synthesis workflow comprises calculating a migration cube output. Rendering a demigration cube output from said migration cube output with a demigration cube calculation. Rendering said synthesized zero-offset wavefield output from said demigration cube output with a zero-offset wavefield synthesis procedure.

A velocity model is generated based upon seismic waveforms via any seismic model building method, such as full waveform inversion or tomography. Data representative of a measurement of a physical attribute of an area surrounding a well is received and an attribute model is generated based upon the velocity model and the data. An image is rendered based upon the attribute model for use with seismic exploration above a region of a subsurface comprising a hydrocarbon reservoir and containing structural or stratigraphic features conducive to a presence, migration, or accumulation of hydrocarbons.

The invention relates to a computer-implemented method for generating an image of a subsurface of an area of interest from seismic data. The method comprises providing seismic wavefields, providing a zero-offset seismic wavefield dataset, determining a seismic velocity parameter model w(x) comprising an initial model w.sub.0(x), a low frequency perturbation term δm.sub.b (x) and a high frequency perturbation term δm.sub.r(x), determining an optimal seismic velocity parameter model w.sub.opt(x) by computing a plurality of iterations, each iteration comprising calculating and optimizing a cost function, said cost function being dependent on the zero-offset seismic wavefield and on the low frequency perturbation term δm.sub.b(x) as a parameter in the optimization of the cost function, the high frequency perturbation term δm.sub.r(x) being related to the velocity parameter model w(x) to keep the provided zero-offset seismic wavefield data invariant with respect to the low frequency perturbation term δm.sub.b(x).

A computer-implemented method for determining a velocity image of a domain of the subsurface structural geology in an oil and gas reservoir comprising an iterative method that combines a migration step and a population step propagating values from regions of the image wherein the velocity is known, or the velocity is according to information being deemed as correct. In this field of the technology this kind of data is also known as hard data. The iterative process uses a seismic image in depth of an initial guess as initial velocity model in a conjunction with tensor properties to generate a new velocity model based on criteria of minimum residual moveout on a specific point(s) or well control location(s). At these locations data information (velocity) is considered as well-known a-prior information to be propagated around the neighborhood guided taking into account the geological structure.

In a general implementation, systems, apparatus, and methods for AVO of imaging condition in ERTM include the described system provides for an efficient and accurate vector wavefield decomposition with a corresponding modified dot-product imaging condition of ERTM by employing a modified AVO algorithm. In some implementations, the phases of source wavelet and multicomponent records are modified using a 1/ω2 filter and the amplitudes of the extrapolated wavefields are scaled using α2 and β2, where ω, α and β are the angular frequency, local P- and S-wave velocities, respectively. The results yield correct phases, amplitudes, and physical units for separated P- and S-mode wavefields. Divergence and curl operators may then be applied to the phase-corrected and amplitude-scaled elastic wavefields to extract vector P- and S-wavefields. With the separated vector wavefields, a modified dot-product imaging condition can be employed to produce PP and PS reflectivity images.

A three-dimensional (3D) seismic data set is divided into a plurality of 3D source wavefield subsets, each 3D source wavefield subset is stored in an array element of an array. For each array element, the associated 3D source wavefield is decomposed into a smaller data unit; data boundaries of the smaller data units are randomly shifted; a folding operation and a sample operator is applied to the smaller data units to keep the smaller data units from overlapping; the folded smaller data units are smoothed to generate smoothed data; a quantization operation is performed on the smoothed data to produce quantized data; and the quantized data is compression encoded to generate compressed data. The compressed data associated with each array element is decompressed to generate a 3D seismic output image.

A method of generating target-oriented acquisition-imprint-free prestack angle gathers using common focus point (CFP) operators includes receiving a plurality of seismic traces associated with a target point in a reservoir. A first angle domain common image gather (ADCIG) is generated based on the received plurality of seismic traces. A plurality of synthetic traces associated with the target point is generated. A second ADCIG is generated based on the synthetic traces. An enhanced ADCIG is generated using the first ADCIG and the second ADCIG.

This disclosure is directed to processes and systems that generate enhanced-resolution seismic images by interpolating sparsely recorded seismic data. Structured dictionary learning is employed to train a set of basis vectors, called “atoms,” and corresponding sparse coefficients on patches of the recorded seismic data. The atoms are constrained to represent the geometric structure of reflection events in the recorded seismic data gather. Linear combinations of the atoms are used to compute interpolated patches over a finer receiver-coordinate grid. The interpolated patches replace the original patches in the recorded seismic data to obtain interpolated seismic data that can be used to generate an image of the subterranean formation.