Chevron U.s.a. Inc.

Wei Liu

Alexander Loddoch

Yue Wang

Kenneth Paul Bube

Thor Mikal Johnsen

Embodiments of a method for implementing a finite difference time domain modeling with multiple APCs are disclosed herein. The disclosed methods and systems overcome the memory capacity limitation of APCs by having each APC perform multiple timesteps on a small piece of the computational domain or data volume in a APC queued manner. The cost of transferring data between host and compute accelerator can then be amortized over multiple timesteps, greatly reducing the amount of PCI bandwidth required to sustain high propagation speeds. The APC queued nature of the algorithm achieves linear scaling of PCI throughput with increasing number of APCs, allowing the algorithm to scale up to many dozens of APCs in some embodiments.

System and method of implementing finite difference time domain models with multiple accelerated processing components (APCS)

A system and method for generating images of a subsurface region of interest is provided. In one embodiment, a computer-implemented method of generating images related to a subsurface region of interest includes: accessing, via a central processing unit (CPU), seismic data and an earth model related to the subsurface region of interest; forward propagating a source wavefield using the earth model at a first time interval via at least one external co-processor coupled to the CPU; transferring, at a second time interval, the forward propagated source wavefield to the CPU for compression and external storage; backward propagating the seismic data at the first time interval via the external co-processor to derive backward propagated receiver wavefield; and transferring, at the second time interval, the backward propagated receiver wavefield to the CPU. Via the CPU, the method further includes retrieving the stored forward propagated source wavefield; decompressing the retrieved forward propagated source wavefield; and applying imaging conditions to the decompressed forward propagated source wavefield and backward propagated receiver wavefield to construct image data representative of the subsurface region of interest.

System and method for generating images of subsurface structures

Images relating to a subsurface region may be generated based at least in part on a backward propagated source wavefield and a receiver wavefield. A source wavefield may be propagated from an initial wavefield-state forward in time, from an initial time-state to a final time-state, through an earth model associated with the subsurface region. The backward propagated source wavefield may be determined by propagating the source wavefield backward in time, from the final time-state to the initial time-state, through the earth model to reconstruct the initial wavefield-state. The receiver wavefield may be propagated, from the final time-state, through the earth model. The earth model may include at least one boundary region that can be defined as having one or more of absorbing characteristics, boosting characteristics, randomly perturbed characteristics, and/or other characteristics. As such, wavefields may be dampened, amplified, randomly scattered, and/or otherwise altered at the at least one boundary region. These wavefields may be used for constructing images of subsurface regions with improved signal-to-noise ratios.

Reverse time migration with absorbing and random boundaries

A computer-implemented method for pseudo acoustic quasi-P wave propagation which remain stable in anisotropic media with variable tilt and is not limited to weak anisotropic conditions. The method includes acquiring a seismic exploration volume for a subsurface region of interest, and determining a modeling geometry for the seismic exploration volume. The method further includes propagating at least one wavefield through the seismic exploration volume utilizing the modeling geometry and initial conditions and preventing the accumulation of energy along the axis of symmetry of the seismic exploration volume and ensuring positive stiffness coefficients in the stress-strain relations through the use of finite quasi-S wave velocities thereby producing a stable wavefield. The method includes utilizing the stable wavefield to generate subsurface images of the subsurface region of interest.

Method for propagating pseudo acoustic quasi-P waves in anisotropic media

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.

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San Ramon, CA, United States of America

Wei Liu