Chevron U.s.a. Inc.

Yue Wang

Guojian Shan

Tamas Nemeth

Yonghe J Sun

Norman Ross Hill

Leonard Lin Zhang

Siwei Li

Chaoshun Hu

Ross K Hill

Wei Liu

N Ross Hill

Tong Xu

Craig Alan Barker

Peeter Akerberg

Shoujian Huang

Linbin Zhang

Jianlei Liu

Sandra Tegtmeier-Last

Fuhao Qin

A method is described for seismic inversion including receiving a processed seismic image and an enhanced seismic image representative of a subsurface volume of interest; forward modeling the processed seismic image and the enhanced seismic image to generate a first modeled dataset and a second modeled dataset; differencing the first modeled dataset and the second modeled dataset to create a residual dataset; filtering the first modeled dataset to generate an approximation of illumination; preconditioning the residual dataset with the approximation of illumination to generate an adjoint source; back projecting the adjoint source to determine a model update; and applying the model update to an earth model of the subsurface volume of interest.

System and method for full waveform inversion of seismic data with reduced computational cost

A method is described for seismic imaging including generating extended image gathers by extended reverse time migration of a seismic dataset using an earth model; processing the extended image gathers to generate processed image gathers; performing extended modeling based on the processed image gathers to generate a modeled seismic dataset; enhancing the processed image gathers to generate an enhanced image; performing extended modeling based on the enhanced image gathers to generate a modeled enhanced dataset; differencing the modeled enhanced dataset and the modeled seismic dataset to determine a data residual; inverting the data residual to generate a model residual; updating the earth model based on the model residual to create an updated earth model; performing seismic imaging of the seismic dataset using the updated earth model to create an improved seismic image. The method may be executed by a computer system.

System and method for seismic imaging of complex subsurface volumes

A method is described for seismic imaging of the subsurface using dip-guided optimized stacking. The method computes weighting functions for a plurality of single-shot migrated images, unstacked seismic images, or partially stacked seismic images based on a slant stack performed using an input dip dataset; applying the plurality of weighting functions to the plurality of single-shot migrated images, unstacked seismic images, or partially stacked seismic images, or a plurality of dip-filtered images to create a plurality of weighted images; and summing the plurality of weighted images into a stacked seismic image. The method may be executed by a computer system.

System and method for dip-guided seismic image stacking

A method is described for processing residual moveout in seismic image data gathers representing critical reflections. The method includes receiving seismic image data arranged as a function of an angle or offset parameter including a high-velocity-contrast event with post-critical. The method also includes applying a wavelet de-stretch filter to the seismic data to correct wavelet stretching. The method also includes applying a fan-filter to remove coherent noise in the one or more post-critical traces; picking residual moveout of the high-velocity-contrast event; adjacent-trace differencing to detect the impact of phase change at critical reflections in residual moveouts, and applying a median-filter to the residual moveout to reduce the impact of phase change of the high-velocity-contrast event in the one or more post-critical traces. The median-filtered and reconstructed residual moveout is used for improving a velocity model used for generating the seismic image gathers.

System and method for velocity analysis in the presence of critical reflections

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.

Predicting interbed multiples in seismic data using beam decomposition

Surfaces may be smoothed within an earth model of a geological volume of interest. More specifically, smoothing may be done on a specific surface by smoothing or otherwise altering dip values without changing the position of the surface within the earth model. Dip values may determine certain behaviors of a surface such as reflection and refraction of seismic energy propagating within the earth model.

Surface smoothing within an earth model of a geological volume of interest

Seismic data representing the propagation of seismic energy through a geologic volume of interest is processed. The seismic energy propagates through the geologic volume of interest from one or more source locations at or near the geologic volume of interest to one or more detector locations at or near the geologic volume of interest. In processing the seismic data, the seismic energy is modeled as beams (e.g., Gaussian beams). The processing performed (i) corrects for misalignment of the one or more source locations and/or the one or more detector locations with a regular, predetermined mesh, and (ii) steers the seismic data based on the modeled beams.

System and method for seismic beam formation that accounts for equipment misalignment

A method for determining values of anisotropic model parameters of a Tilted Transversely Isotropic (TTI) Earth model, the method including obtaining an initial TTI earth model that substantially flattens common-imaging-point gathers and substantially ties seismic data to well data; inputting checkshot data and/or VSP data to determine updated values of Vpnear the well locations; determining an incremental improvement &#x394;&#x3b4;; extrapolating the relative change &#x394;&#x3b4; from near-well locations to the entire three dimensional TTI earth model; determining updated values of Vp=Vp(1&#x2212;&#x394;&#x3b4;); inputting near-to-mid-offset/angle and mid-to-far-offset/angle residual moveout information; and providing updated values of &#x3b4; and &#x3b7;.

Multiple anisotropic parameter inversion for a TTI earth model using well data

Seismic data representing the propagation of seismic energy through a geologic volume of interest is processed. The seismic energy propagates through the geologic volume of interest from one or more source locations at or near the geologic volume of interest to one or more detector locations at or near the geologic volume of interest. In processing the seismic data, the seismic energy is modeled as beams (e.g., Gaussian beams). The processing includes determining a filter for the seismic data that attenuates aliasing which may be present in the seismic data due to spacing between detector locations.

System and method for attenuating aliasing in seismic data caused by acquisition geometry

A system and computer-implemented method for accounting for temporal dispersion in low-order finite difference seismic wave propagation is disclosed. An embodiment of the method includes transforming a seismic dataset from time domain to frequency domain to obtain a frequency-domain seismic dataset, applying a frequency-domain time varying filter to the frequency-domain seismic dataset to obtain a filtered frequency-domain seismic dataset, and transforming the filtered frequency-domain seismic dataset from the frequency domain to the time domain to obtain a time-domain filtered seismic dataset. The frequency-domain time varying filter is based on the effective phase velocity inherent in a finite-difference solution to the wave equation. The frequency-domain time varying filter may be applied to a synthetic seismic dataset that was generated by low-order finite difference modeling. A different frequency-domain time varying filter may be applied to recorded seismic data prior to reverse time migration.

System and method for seismic data modeling and migration

Beamed data can be obtained from shot gather data, and debeamed data can be obtained from beamed data. Shot gather data for a geophysical volume of interest in a first domain and/or beamed data in a third domain may be received. The first domain has a component relating to seismic wave propagation time and a spatial component relating to lateral spacing. The third domain has a component relating to local plane wave arrival time at a beam center surface location and a component relating to plane wave arrival directions. Data may be transformed between the first domain and a second domain. The second domain has a frequency component and a spatial component corresponding to the spatial component of the first domain. A forward or reverse transform may be applied to transform shot gather data in the first domain to/from beamed data in the third domain.

Shot gather data beamer and debeamer

A method and system for target-oriented reverse time migration for prestack depth imaging. One embodiment of the present invention includes determining an acquisition area within an earth model and also determining a reference surface near a target in the subsurface region of interest. The embodiment includes exciting wavefields from the reference surface and propagating the excited wavefields through the earth model. The embodiment additionally includes recording the wavefields at receiver locations in the acquisition area and at the target and synthesizing wavefields along the reference surface to reconstruct Green's functions which relate the receiver locations in the acquisition area to the target. The embodiment includes utilizing the Green's functions and prestack seismic data to determine subsurface characteristics of the subsurface region.

Method for target-oriented reverse time migration for prestack depth imaging

A system and method that enable the processing of seismic data. In one embodiment, a system comprises a plurality of processing nodes and a server. The plurality of processing nodes are configured to process seismic data for migration. The server is operatively linked to each of the plurality of processing nodes to enable communication between the server and the processing nodes. The server may manage a set of stored beam tables that can be accessed by the processing nodes in order to process seismic data.

System and method for migrating seismic data

The present invention incorporates the use of model-driven and data-driven methodologies to attenuate multiples in seismic data utilizing a prediction model which includes multiply-reflected, surface-related seismic waves. The present invention includes beam techniques and convolving a predicted multiples beam with a segment of a modeled pegleg beam to obtain a convolved multiples beam. The convolved multiples beam can then he deconvolved to attenuate the multiples that are present in the original input beam.

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Danville, CA, United States of America

Yue Wang