Compressing seismic wavefields in three-dimensional reverse time migration

Abstract

A three-dimensional (3D) seismic data set is divided into a plurality of 3D source wavefield subsets, each 3D source wavefield subset is stored in an array element of an array. For each array element,the associated 3D source wavefield is decomposed into a smaller data unit; data boundaries of the smaller data units are randomly shifted; a folding operation and a sample operator is applied to thesmaller data units to keep the smaller data units from overlapping; the folded smaller data units are smoothed to generate smoothed data; a quantization operation is performed on the smoothed data toproduce quantized data; and the quantized data is compression encoded to generate compressed data. The compressed data associated with each array element is decompressed to generate a 3D seismic output image.

Description

[0001] priority statement

[0002] This application claims priority to US Patent Application No. 62 / 484,101, filed April 11, 2017, the entire contents of which are hereby incorporated by reference. Background technique

[0003] Seismic imaging is a tool that bounces sound waves off subsurface structures, such as rocks and other sedimentary layers or cavities, to reveal possible oil-bearing formations. Reverse time migration (RTM) is a seismic imaging method that provides accurate imaging in and below regions of complex structures and velocities. In RTM, seismic images are generated by zero-delay cross-correlation of source and receiver wavefields. The source wavefield is computed by forward propagation, while the receiver wavefield is computed by backward propagation. Due to the opposite directions of propagation relative to the source and receiver wavefields, the RTM first computes data for the entire source wavefield and stores this data in a data storage location such as ...

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