Multioffset 3-C VSP processing and coal-seam anisotropy: An Alberta case history

Zandong Sun, Peter Manning and R. James Brown

ABSTRACT

Alberta coal causes imaging ambiguities in the case of a reef underneath coal on conventional seismic data in areas where coal is present. A multioffset 3-C VSP experiment was carried out in a 3-D prospect area. The data were processed for a comparison of resolution between 3-D surface data and multioffset VSP and as a coal anisotropy study. Converted-wave processing is employed in this paper, and the anisotropic feature due to coal fracture is presented. The time shift (about 6 ms) between the radial- and transverse-component CCP stack sections is due to a group of dominant fractures oriented SE-NW. It is much easier for shear waves to propagate through a coal medium than compressional waves.

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