Exxonmobil Upstream Research Company

Exxonmobil Technology and Engineering Company

Carey M Marcinkovich

John E Anderson

Valeriy V Brytik

Jerome R Krebs

Anatoly I Baumstein

Partha Sarathi Routh

Spyridon K Lazaratos

Sunwoong Lee

Rongrong Lu

Hongchuan Sun

Tetyana Vdovina

Jaewoo Park

Ramesh Neelamani

Thomas A Dickens

Junzhe Sun

Wenyi Hu

William Curry

Hong Zhao

Erik R Neumann

Lorie K Bear

Sirui Tan

Gboyega Ayeni

Peter Traynin

Jia Yan

Feng Deng

Spyridon Lazaratos

Spyridon Lazarato

A method for partitioning a search direction when using least squares reverse time migration (LSRTM) is provided. LSRTM may be used iteratively in order to improve imaging accuracy. As part of LSRTM, multiple local line searches may be performed. In particular, image space may be partitioned, such as by using a set of masks. The search direction, such as the gradient, may be partitioned using the set of masks. Local line searches may be performed for each partition of the search direction, resulting in finding respective line search constants. The respective line search constants may then be used for iterating the model in order to improve imaging accuracy.

Method for partitioning a search direction when using least squares reverse time migration

Iterative methods for inversion of seismic data to update a physical property model are disclosed. Such methods may comprise iteratively updating the model until a first predetermined resolution is achieved, using full wavefield inversion of the seismic data up to a first frequency threshold and assuming the seismic data is free of attenuation effects; extracting geobodies from the updated model; obtaining a Q model using the geobodies; and updating the physical property model using an inversion process, wherein the Q model is incorporated into the inversion process. These steps may be repeated until a second predetermined resolution of the physical property model is achieved, wherein the first frequency threshold is progressively increased in each repetition. The Q model may be updated with seismic data at all available frequencies to obtain a full-band Q model; and the physical property model may be updated using full-band migration and the full-band Q model.

Accurate velocity model estimation and imaging in the presence of localized attenuation (Q) anomalies

A method, including: generating updated velocity models, each corresponding to one of a plurality of initial velocity models of intersecting 2D seismic survey lines, wherein updates to the plurality of initial velocity models are computed by imposing a seismic-tie regularization constraint on an inversion process that inverts for the updates to the plurality of initial velocity models, and the seismic-tie regularization constraint causes the updated velocity models to have consistent values for depth of seismic reflectivity at intersecting spatial locations.

2D multiline seismic reflection tomography with seismic-tie constraint

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 reconstructing subsurface Q depth profiles from common offset gathers () of reflection seismic data by performing migration (), ray tracing (), CDP-to-surface takeoff angle finding (), kernel matrix construction (), depth-to-time conversion and wavelet stretching correction (), source amplitude spectrum fitting, centroid frequency shift calculation (), and box-constrained optimization ().

Reflection seismic data Q tomography

A method for generating seismic attribute gathers, the method including: computing, with a computer, seismic images with a field dataset; generating, with a computer, synthetic data corresponding to the seismic images; computing, with a computer, an attribute volume by applying an expectation method to the synthetic data; mapping, with a computer, the attribute volume to the seismic images; and generating, with a computer, seismic attribute gathers by stacking the seismic images mapped to the attribute volume.

Efficient seismic attribute gather generation with data synthesis and expectation method

Method for correcting seismic simulations, RTM, and FWI for temporal dispersion due to temporal finite difference methods in which time derivatives are approximated to a specified order of approximation. Computer-simulated seismic data () are transformed from time domain to frequency domain (), and then resampled using a mapping relationship that maps, in the frequency domain, to a frequency at which the time derivative exhibits no temporal dispersion (), or to a frequency at which the time derivative exhibits a specified different order of temporal dispersion. Alternatively, measured seismic data from a field survey () may have temporal dispersion of a given order introduced, by a similar technique, to match the order of approximation used to generate simulated data which are to be compared to the measured data.

Method for temporal dispersion correction for seismic simulation, RTM and FWI

Method for estimating reflector dips in a window of post stack image traces () of seismic data for use in velocity tomography (). The method iteratively () flattens () the image traces against a specified reference trace through the application of conjugate-gradient least-squares inversion (). Different from other dip estimation methods which emphasize on strong-amplitude reflectors, the inventive method automatically inverts for the reflector dip for every grid point in the image window.

Inversion-based reflector dip estimation

Method for simultaneous full-wavefield inversion of gathers of source (or receiver) encoded geophysical data to determine a physical properties model () for a subsurface region, especially suitable for surveys where fixed receiver geometry conditions were not satisfied in the data acquisition. Simultaneous source separation () is performed to lessen any effect of the measured geophysical data's not satisfying the fixed-receiver assumption. A data processing step () coming after the simultaneous source separation acts to conform model-simulated data () to the measured geophysical data () for source and receiver combinations that are missing in the measured geophysical data.

Simultaneous source encoding and source separation as a practical solution for full wavefield inversion

Method for simultaneous full-wavefield inversion of gathers of source (or receiver) encoded geophysical data to determine a physical properties model for a subsurface region, especially suitable for surveys where fixed receiver geometry conditions were not satisfied in the data acquisition. First, a shallow time window of the data () where the fixed receiver condition is satisfied is inverted by simultaneous encoded () source inversion (). Then, the deeper time window of the data () is inverted by sparse sequential source inversion (), using the physical properties model from the shallow time window () as a starting model (). Alternatively, the shallow time window model is used to simulate missing far offset data () producing a data set satisfying the stationary receiver assumption, after which this data set is source encoded () and inverted by simultaneous source inversion ().

Growing community of inventors

The Woodlands, TX, United States of America

Carey M Marcinkovich