"Dispersion and attenuation of seismic waves in fractured reservoirs"
Boris Gurevich (Curtin University)
The detection and characterization of domains of intersecting fractures are important goals in several disciplines of current interest, including exploration and production of unconventional reservoirs, nuclear waste storage, CO2 sequestration, and groundwater hydrology, among others. The objective of this study is to quantify the effects of fracture intersections on the frequency-dependent elastic properties of fluid-saturated porous and fractured rocks. Three characteristic frequency regimes for fluid pressure communication are identified. In the low frequency limit, fractures are in full pressure communication with the embedding porous matrix and with other fractures. Conversely, in the high frequency limit, fractures are hydraulically isolated from the matrix and from other fractures. At intermediate frequencies, fractures are hydraulically isolated from the matrix porosity, but can be in hydraulic communication with each other, depending on whether fracture sets are intersecting. The theoretical predictions for each regime show good agreement with corresponding numerical simulations. The theoretical results are applicable not only to 2D but also to 3D fracture.