Research and Development of Capillary Imbibition Regularity in Ultra-Low Permeability Oil Reservoirs

Nowadays, Chinese economy is growing rapidly, and the petroleum industry is developing swiftly. The demand for oil and gas resources is increasing day by day. As the development process goes deeper, a significant portion of our country’s oil fields has entered the stage of high-water content and high recovery. Consequently, the direction of oil and gas exploration is gradually shifting towards unconventional reservoirs. Special low-permeability oil reservoirs in China exhibit characteristics such as low porosity, low permeability, fine pores, and natural fractures. Their recovery rates are low. Hence, the exploration and development of these special low-permeability oil reservoirs have become a critical challenge in today’s petroleum engineering domain. The urgent task is to find ways for high-yield, high-efficiency, and sustainable development of such reservoirs. In the development process of these special low-permeability oil reservoirs, capillary action plays a significant role. Capillary action allows the transportation of high-density crude oil within the reservoir, potentially enhancing the recovery rates of special low-permeability oil reservoirs. In recent years, both domestically and internationally, there has been extensive research on the mechanisms and patterns of water injection and capillary action. This paper delivers the research on capillary action in special low-permeability oil reservoirs, summarizes and organizes the progress and achievements in this field, aiming to deepen the understanding of this area and provide insights into future research directions.