Azimuthal AVO Modeling for Fractured Zones Identification – a Feasibility Case Study

Fractured zones are of great interest because they generally lead to higher reservoir permeability. Forward seismic modeling is essential when studying the ability of azimuthal AVO attributes to detect such zones. For proper modeling, one has to determine effective elastic parameters of a fractured reservoir using all available core and well log information.

In this paper, linear slip theory and penny-shaped crack model are utilised to integrate borehole micro-imaging and cross-dipole sonic logging data obtained in a single well. Fracture properties are used to estimate the properties of an anisotropic effective medium corresponding to the zone of interest. Seismic modeling shows the expected azimuthal response and allows determining optimal attributes to study the presence and properties of fractures. This study also analyses stability of AVOAz-attributes when the data is contaminated by random noise.