Exxonmobil Upstream Research Company

Reeshidev Bansal

Anatoly I Baumstein

Michael P Matheney

Spyridon K Lazaratos

Di Yang

Partha Sarathi Routh

Pavel Dimitrov

Yaxun Tang

Tetyana Vdovina

Hongchuan Sun

Jonathan Liu

Jia Yan

Sergey Fomel

Vijay Khare

Eric G Wildermuth

Alexander A Martinez

A multi-stage FWI workflow uses multiple-contaminated FWI models to predict surface-related multiples. A method embodying the present technological advancement, can include: using data with free surface multiples as input into FWI; generating a subsurface model by performing FWI with the free-surface boundary condition imposed on top of the subsurface model; using inverted model from FWI to predict multiples; removing predicted multiples from the measured data; using the multiple-free data as input into FWI with absorbing boundary conditions imposed on top of the subsurface model; and preparing a multiple free data set for use in conventional seismic data processing.

Multistage full wavefield inversion process that generates a multiple free data set

A method, including: obtaining a seismic dataset that is separated into subsets according to predetermined subsurface reflection angle ranges; performing, with a computer, an acoustic full wavefield inversion process on each of the subsets, respectively, to invert for density and generate respective density models; generating acoustic impedances for each of the subsets, as a function of reflection angle, using the respective density models; and transforming, using a computer, the acoustic impedances for each of the subsets into reflectivity sections, wherein the transforming includes normalizing the reflectivity sections by their respective bandwidth.

FWI model domain angle stacks with amplitude preservation

A deterministic method for selecting a set of encoding weights for simultaneous encoded-source inversion of seismic data that will cause the iterative inversion to converge faster than randomly chosen weights. The encoded individual source gathers are summed (), forming a composite gather, and simulated in a single simulation operation. The invention creates multiple realizations of the simulation (), each with its own encoding vector () whose components are the weights for the shots in the composite gather. The encoding vectors of the invention are required to be orthogonal (), which condition cannot be satisfied by random weights, and in various embodiments of the invention are related to eigenvectors of a Laplacian matrix, sine or cosine functions, or Chebyshev nodes as given by the roots of Chebyshev polynomials. For non-fixed receiver geometry, an encoded mask () may be used to approximately account for non-listening receivers.

Harmonic encoding for FWI

A method, including: obtaining a velocity model generated by an acoustic full wavefield inversion process; generating, with a computer, a variable Q model by applying pseudo-Q migration on processed seismic data of a subsurface region, wherein the velocity model is used as a guided constraint in the pseudo-Q migration; and generating, with a computer, a final subsurface velocity model that recovers amplitude attenuation caused by gas anomalies in the subsurface region by performing a visco-acoustic full wavefield inversion process, wherein the variable Q model is fixed in the visco-acoustic full wavefield inversion process.

Q-compensated full wavefield inversion

The present disclosure provides a system and method for estimating fracture density within a subsurface formation from S-wave seismic data. In one embodiment, the S-wave seismic data is separated into fast ('S') and slow ('S') data. A computer is used to compute local similarity of the Sand Sdata and to compute a cumulative time-difference by which the Sdata lags the Sdata from the local similarity. Based on the computed cumulative time-difference, the fracture density of a subsurface formation is estimated.

S-wave anisotropy estimate by automated image registration

Method for using the full wavefield (primaries, internal multiples and free-surface multiples) in inversion of marine seismic data, including both pressure and vertical velocity data (), to infer a subsurface model of acoustic velocity or other physical property. The marine seismic data are separated () into up-going () and down-going () wavefields, and both wavefields are inverted in a joint manner, in which the final model is impacted by both wavefields. This may be achieved by inverting both wavefields simultaneously (), or one after the other, i.e. in a cascaded approach (, or), for the subsurface properties ().

Full-wavefield inversion of primaries and multiples in marine environment

The present disclosure provides a system and method for inferring one or more physical property parameters of a subsurface media by inverting converted wave data acquired during a seismic survey. Composite seismic traces are generated at a plurality of survey azimuths (step). These composite traces are composed such that their amplitudes are free of effects of subsurface anisotropy. At least one of the generated composite seismic traces is then inverted by isotropic inversion to determine a property parameter of the subsurface media (step).

Removal of fracture-induced anisotropy from converted-wave seismic amplitudes

Method for aligning converted wave seismic reflection data (PS data) with conventional PP seismic reflection data so that both data types may be used to more accurately image the subsurface for hydrocarbon exploration or field development. Amplitude vs. angle (AVA) or amplitude vs. offset (AVO) attributes of PP and PS seismic data are identified and defined, which attributes are theoretically expected to be in phase and optimize seismic resolution in the data. In one embodiment of the invention, such attributes are calculated (), then the same horizons are identified in a series of PP attributes and in a series of PS attributes, then the second series is aligned with the first at the horizon locations (), then a time transfer function is generated and applied to the PS mode data (), and the aligned joint-mode data are inverted () using, for example, AVA attributes.

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Spring, TX, United States of America

Reeshidev Bansal