Exxonmobil Upstream Research Company

William Curry

Thomas A Dickens

Yaxun Tang

Dennis E Willen

John E Anderson

Pavel Dimitrov

Partha Sarathi Routh

Carey M Marcinkovich

Valeriy V Brytik

Young Ho Cha

Martin J Terrell

Tetyana Vdovina

Ethan J Nowak

Fuxian Song

William A Burnett

A method, including: determining, with a computer, point spread functions for a plurality of parameter locations by performing at least a portion of a first iteration of an iterative full wavefield inversion process; determining at least one property for each of the point spread functions; and evaluating a candidate survey design based on the at least one property for each of the point spread functions.

Method to design geophysical surveys using full wavefield inversion point- spread function analysis

A computer-implemented method for generating missing frequencies within geophysical data, said method including: decomposing, with a computer, geophysical data into frequencies and slowness or wavenumber along time and one or more spatial dimensions; estimating, with a computer, a filter across known frequencies within the geophysical data for each time, spatial dimension, and slowness or wavenumber sample; extrapolating or interpolating, with a computer, the missing frequencies from the known frequencies by applying the filter; recomposing, with a computer, the known frequencies and the missing frequencies back into time and the one or more spatial dimensions; and prospecting for hydrocarbons with geophysical data that includes the missing frequencies.

Fabrication of unrecorded data by Gaussian slowness period packet extrapolation

A method for exploring for hydrocarbons, including: simulating a seismic waveform, using a computer, wherein computations are performed on a computational grid representing a subsurface region, said computational grid using perfectly matched layer (PML) boundary conditions that use an energy dissipation operator to minimize non-physical wave reflections at grid boundaries; wherein, in the simulation, the PML boundary conditions are defined to reduce computational instabilities at a boundary by steps including, representing direction of energy propagation by a Poynting vector, and dissipating energy, with the dissipation operator, in a direction of energy propagation instead of in a phase velocity direction; and using the simulated waveform in performing full waveform inversion or reverse time migration of seismic data, and using a physical property model from the inversion or a subsurface image from the migration to explore for hydrocarbons.

Poynting vector minimal reflection boundary conditions

Method for locating fault lines or surfaces in 2-D or 3-D seismic data based on the fact that fault discontinuities in the space domain span a wide range in a local slowness (slope) domain, whereas other dipping events in the space domain data, such as noise, tend to be coherent, and hence will appear focused in the slowness dimension. Therefore, the method comprises decomposing the seismic data () by a transformation to the local slowness domain, preferably using Gaussian slowness period packets as the local slowness or slope decomposition technique, thereby avoiding problems with the data stationary assumption. In the local slowness domain, faults may be identified () using the principle mentioned above, i.e. that faults are represented as a truncation in the space domain data, hence they will appear broadband in the slowness dimension.

Automatic tracking of faults by slope decomposition

Method for optimal stacking of seismic images to remove noise and enhance signals in seismic images () outputted from a Reverse Time Migration (RTM) imaging process. Dip information is calculated () and then sorted by image point (), for each seismic image to be stacked. A dominant dip and azimuth is determined at each image point (), and only those events are stacked (). If the image is still noisy or lacking in detail (), the process may be iterated () to improve the selection of most likely dip and azimuth.

Seismic image dip decomposition estimation and recomposition

Method for addressing non-stationary seismic data for data processing techniques () that assume that the data are stationary. In the present invention, windowing operations are applied, not in time and space as in traditional methods, but in frequency and wavenumber. This windowing in frequency and wavenumber is done implicitly by a cascade of separable one dimensional time and spatial filtering operations (). These filters are Gaussian functions modulated by a complex exponential. By using a variety of these filters, the input data can be decomposed into a series of slopes and frequencies that can be reassembled to the original by applying the adjoint operation followed by a weighted sum (). This decomposed domain of time, space, frequency and slope can be used as a domain where a priori information about the output can be applied in a straightforward manner.

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Houston, TX, United States of America

William Curry