Flow-through experiments were performed for single tensile fractures artificially created in granite, using Rubber-Confining Pressure Vessel (R-CPV), which has been developed for the experiments under relative high confining pressure conditions up to 100 MPa. The experimental results showed great differences in permeability depending on degree of offset along the fracture surface. In case of the fractures without offset, permeability decreased significantly with increasing confining pressure until around 40-50 MPa, beyond which the permeability, however, decreased gradually and then became constant, and remained much higher than that of rock matrix even at 100 MPa. In case of the fractures with 1, 3, 5 and 10 mm offset, permeability was much higher than that of the fractures without offset. The behavior of permeability for increase of confining pressure, however, drastically changed between 1 mm and other offset conditions. No obvious decrease of permeability was observed with increasing confining pressure in case of 3, 5 and 10 mm offset, while permeability decreased continuously until 70 MPa and abrupt decrease was also observed at 80 MPa in case of 1 mm offset. Those results indicate understanding of offset conditions is a key factor for prediction of productivity in oil/gas fractured reservoir.
