The lattice Boltzmann method is widely used in the simulation of digital core porous media flow because it can handle complex geometric boundaries.The digital core section of the Dongying formation reservoir in the Bohai S oilfield is taken as the research object. Based on the image processing, the lattice Boltzmann method is used to carry out the two⁃dimensional pore flow simulation and velocity field characterization. By changing the simulation conditions, the different production pressure differences are analyzed. The effect of pore throat optimization on the slice seepage channel. The results show that the production pressure difference can only change the seepage strength of each channel. The rock pore size is the main factor affecting the distribution of the seepage channel. The pore throat optimization can effectively adjust the seepage channel and improve the microscopic pore wave degree.

Oil displacement efficiency is one of the important parameters affecting the oil reservoir recovery, and the pore volume injection rate is the decisive factor that directly affects the ultimate oil displacement efficiency in the sweep zone. The semi quantitative relationship between the displacement efficiency and the injection volume of pore volume is derived by using the percolation equation expressed by the phase permeability index, combining with the BL theory and the Welge equation. The relation curve satisfies the life cycle theory and the quantitative relation expression between them is deduced according to the law of Logistic growth. At the same time, the optimal pore volume injection ratio is determined by the twoorder derivative curve. With the oil field entering the high water cut stage, the quantitative evaluation method of oil displacement efficiency is of great significance for evaluating the development effect of water flooding reservoir and tap the potential of the reservoir.