Experimental Study on Physical Simulation of Large-Scale Interfracture Injection and Production with Different Injection Media in Tight Oil Reservoirs

Abstract

AbstractGiven the difficulty of water injection and effective displacement system establishment in Changqing oilfield, this research carried out the interfracture injection and production experiment of a large outcrop model with two types of injection fluid medium, natural gas and surfactant, and studied the interfracture injection and production law of different displacing medium and the principal contradiction existing in the different displacing medium. The results show that natural gas drive in tight oil reservoir is beneficial to reduce the Jamin resistance and form a rapid oil production. Still, the gas drive process is easy to develop gas breakthrough, leading to a decrease in gas utilization ratio, and its oil displacement efficiency is 17.25%. Additionally, due to the strong adsorption of surfactant, the seepage capacity of a porous medium in the process of surfactant-oil displacement is reduced, and blockage is formed at the injection end, resulting in the poor oil displacement effect of surfactant. However, compared with natural gas injection, the surfactant has higher oil displacement efficiency, up to 22.05%. Therefore, for tight oil reservoirs, rational utilization of the advantages of different mediums and controlling their disadvantages are essential for the development of such reservoirs.