FLUID-FLOW ALONG POTENTIALLY ACTIVE FAULTS IN CRYSTALLINE ROCK

The relationship between in-situ stress and fluid flow in fractured an d faulted rock is examined by using data from detailed analyses of str ess orientation and magnitude, fracture geometry, and precision temper ature logs that indicate localized fluid flow. Data obtained from thre e boreholes that penetrate highly fractured and faulted crystalline ro cks indicate that potentially active faults appear to be the most impo rtant hydraulic conduits in situ. The data indicate that the permeabil ity of critically stressed faults is much higher than that of faults t hat are not optimally oriented for failure in the current stress field .