Chevron U.s.a. Inc.

Guojian Shan

Yue Wang

Siwei Li

Linbin Zhang

Yonghe J Sun

Craig Alan Barker

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 computer-implemented method, system, and article of manufacture for generating images of a subsurface region are disclosed. The method includes obtaining seismic data and an earth model related to the subsurface region, forward propagating a source wavefield through the earth model for a limited time range dependent on a first travel time and a second travel time, backward propagating a receiver wavefield through the earth model for the limited time range dependent on the first travel time and the second travel time, and applying an imaging condition to the forward propagated source wavefield and backward propagated receiver wavefield to generate images related to the subsurface region. The first travel time is a length of time taken by seismic energy to travel from a seismic source to an image point in the subsurface region and the second travel time is a length of time taken by seismic energy to travel from a seismic receiver to the image point in the subsurface region. The limited time range is between the first travel time and the second travel time subtracted from a maximum travel time.

System and method for seismic imaging with reduced computational cost

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.

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Sugar Land, TX, United States of America

Guojian Shan