Morphology evolution of water flooding front in tight sandstone cores

Abstract:

The development effect of water flooding in tight sandstone reservoirs is closely related to the morphology of water flooding front， so accurate prediction of the water flooding front topography is the key to evaluating the water flooding development effect of tight sandstone reservoirs. Most current water flooding front evolution models assume that the reservoirs are homogeneous and do not consider the microstructures of the reservoirs， so they cannot effectively predict the evolution law of the water flooding front in tight sandstone reservoirs. In this work， by combining the water flooding front morphology evolution tests， and the fractal theory， the evolution of the average displacement and the fractal dimension of water flooding front in tight sandstone reservoirs are studied. On this basis， by combining the Langevin equation， the stochastic theory， and the Buckley-Leverett theory， a theoretical model for predicting the water flooding front evolution in tight sandstone reservoirs is established. The results show that the theoretical calculation is in good agreement with the experimental results， which verifies the correctness of the theoretical model. The boundary position of water flooding front in tight sandstone reservoirs is influenced by the macroscopic average displacement （controlled by the Buckley-Leverett theory） and the fractal dimension of water flooding front topography （controlled by water phase viscosity and rock heterogeneous pore structures）. The results reveal the physical and mechanical mechanism of complex displacement boundaries caused by water flooding in tight sandstone reservoirs.