Finely Layered Anisotropic Media Effect On Seismic Reservoir Characterization

Anisotropic terms of elastic wave equations make it much more complicated, that is why usually earth is assumed isotropic. Anisotropy effect arising from shale layers (clastic and also unconventional reservoirs) need to be corrected in seismic imaging as a function of travel time and in seismic reservoir characterization as a function of amplitude. In this study the influence of anisotropy on amplitude variation with offset (AVO) is analyzed. In AVO response, the amplitude changes should be evaluated and determine that how much originates from hydrocarbon and how much is due to anisotropy effect. In order to overcome the plausible misleading of interpretation after seismic simultaneous pre-stack inversion, anisotropy correction on seismic data is carried out. To do so, Backus averaging is performed to predict anisotropic parameters. Afterwards, in different seismic angle stacks, amplitude correction is exerted according to the specified incident angle and estimated Thomsen parameters. The inversion results derived from corrected data reduce the uncertainty of hydrocarbon prediction and leads to far more accurate reserve estimation which in turn positively affects on drilling costs.