Characterization of Residual Dispersion in High Water Cut Reservoir

Abstract Minghua Formation in Gangdong Oilfield belongs to high permeability reservoir. The dispersion degree of residual oil is a very important production target. The dominant reserves in reservoirs are extracted by the abundance parameters of residual dominant reserves. The residual oil dispersion degree is characterized by the index of unit area, distribution density and shape index, and the weight of each index is determined by the entropy weight method. Finally, the residual oil fraction is formed. The results show that for a stable reservoir, the residual oil dispersion in different development stages include the following stages: rising, rapid rising, fluctuating downward and secondary rising. The characterization index is used to evaluate the Nm3-4-1 formation of Gangdong oilfield. The residual oil dispersion of the formation increases steadily with the development. At present, the residual oil dispersion begins to decrease. The new characterization method of residual oil dispersion effectively reflects the stage effect of reservoirs and provides a basis for improving oil recovery.