Effect of Patchy Saturation and Pore Structure In Carbonates

Carbonate reservoirs often present high permeability streaks. We hypothesize that these streaks give rise to heterogeneous or patchy saturation in the rocks. Patchy saturation produces higher seismic velocities than homogenous saturation. Seismic velocities in carbonates are also related to the rock's internal pore structure. Although the scales of saturation patches and pores are different, they seem to be connected. Hence, the effect of pore structure in patchy saturation needs to be better understood. In this paper, we present preliminary results of a study on saturation distribution, pore structure and seismic response in carbonates. We use core samples, well logs and production data from a Middle East carbonate reservoir. We identify zones of high permeability streaks using rock properties, seismic velocities, and numerical models. Our preliminary results indicate that patchy saturation acoustic model potentially identifies non-homogenous saturation using sonic logs.