Conditioning Prestack Seismic Data in the Offset-azimuth Domain

摘要

These days acoustic and elastic impedance are commonly derived from 3-D seismic data, which help us compute porosity and reservoir fluid estimates. Somewhat less commonly, vertical fracture density and fracture orientation in the reservoir rocks are derived from seismic data, enhancing our ability for optimum placement of horizontal wells and optimal recovery. To achieve the latter objective, good quality seismic data are required, which might be acquired not only with such objectives in mind, but also to yield data with good signal-to-noise ratio. The processing sequence adopted for the seismic data employs all the usual steps, including 5-D interpolation used for regularization of the offset and azimuth sampling within common mid-point, or CMR gathers. Thereafter, the common procedure is to azimuthally sector the gathers (six sectors of 30 degrees each), and put them through the azimuthal amplitude variation with offset, or AVO, analysis procedure to determine the fracture density and orientation.