Numerical modeling of a fractured medium

Faranak Mahmoudian, Gary F. Margrave

Fractures play an important role in hydrocarbon production. A fractured layer often induces a transverse anisotropy with a horizontal symmetry axis (HTI) layer in response to seismic wave propagation. We have created numerical 3D seismic data from a fractured model, using a 3D finite-difference anisotropic program called TIGER. The effect of the fractured layer on the seismic response has been examined, and it is observed that the HTI medium affected the amplitude and travel time of both P- and S-waves. P-wave amplitude is highest in the direction of fracture strike. The TIGER code was able to create an accurate 3D dataset with minimal dispersion. The investigation of synthetic data for a fractured layer will help in fracture detection and estimation from surface seismic data. This model will be used to calibrate a common-angle migration algorithm, whose purpose is to generate common-angle gathers essential in an amplitude-versus-angle and azimuth (AVAZ) analysis, an effective method in fracture detection.