Study on the Rock-Electric Characteristics by using P-Wave Velocity in Cracked Porous Rocks

There usually exists large numbers of cracks in fractured tight reservoirs, which has a significant effect on both the conductive and the elastic properties. In this paper, we present the cross-property relation between the conductivity and P-wave velocity in cracked porous rocks, and infer the conductivity from P-wave velocity. By establishing this cross-property relation, we can introduce crack parameters (crack density) into the study of the rock-electric characteristics. The study shows that it is necessary to consider the effect of cracks on the rock-electric characteristics in tight rocks, the existence of cracks not only enhances the conductive ability but also leads to the low resistivity oil layers and the non-Archie phenomenon. Besides, by the comparison with logging data, the results of numerical experiments prove that this method has advantage on the study of the rock-electric characteristics in fractured tight reservoirs.