Frequency-dependent seismic anisotropy and its implication for estimating fracture size in low porosity reservoirs

Abstract

The use of seismic anisotropy for characterizing subsurface fracture orientations and intensity has become increasingly popular. However, the reluctance of reservoir engineers to accept seismic anisotropy as a routine technique for fracture characterization is partly because of its inability to provide information about sizes and volume of fractures. Although both grain-scale micro-cracks and formation-scale macro-fractures are considered causes of seismic anisotropy, reservoir engineers are more interested in the latter as permeability in many hydrocarbon reservoirs is believed to be dominated by formation-scale fluid units (on the order of meters). We intend to fill this gap by developing new practical applications of seismic anisotropy including new theoretical models and new analysis methods.