Summary

Natural fault zones are composed of clusters of sub-seismic scale faults (<30 m throw) adjacent to larger faults which together form a complex deformation volume or damage zone. The hydraulic properties of fault zones are complex, with the connectivity of the sub-seismic faults dictating the effectiveness of this zone to act as a barrier (if the faults have reduced permeability) or as a conduit (if the faults/fractures are partially open). We will present a new Fault Zone Flow Model which uses the statistical properties of a population of faults (size-frequency, clustering and orientation distribution) and evaluates the efficiency of flow through the fault networks. The assumptions of the model are that the faults are members of a fractal population, that all faults are elliptical (with a definable long:short axis ratio) and that all “large” faults have a damage zone of clustered smaller faults. We have determined the impact of fault networks on percolation behaviour, determining the sensitivity of fault orientation and the fractal gradient of the fault population on the resultant percolation pathways.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah