Anisotropic Imaging and Attribute Generation in a Complex Fractured Reservoir

In this study, an integrated workflow involving advanced depth velocity modelling and imaging is applied to multi- and wide-azimuth seismic data in order to estimate anisotropy attributes, such as fracture intensity and fracture orientation through AVAZ. The full azimuth 3D seismic dataset revealed strong spatially variable azimuthal velocity anisotropy. This has been taken into account by including residual moveout estimation in azimuth sectors, velocity model update with azimuthal anisotropy and subsequent APSDM. After the advanced depth velocity modelling and imaging, sector azimuth stacks are geostatistically decomposed into "common part" and noise free anisotropic component and subsequently utilized to estimate fracture intensity and fracture orientation. The results are in good agreement with expected fracture and in-situ stress orientation and are currently being used as the basis for accurate positioning and the determination of fracture zones, which are the most critical factors controlling production in the studied field.