CO₂ flooding can significantly improve the recovery rate, effectively recover crude oil, and has the advantages of energy saving and emission reduction. At present, most domestic researches on CO₂ flooding seepage experiments are field tests in actual reservoirs or simulations with reservoir numerical simulators. Although targeted, the promotion is poor. For the characterization of seepage resistance, there are few studies on the variation law of seepage resistance caused by the combined action in the reservoir. To solve this problem, based on the mechanism of CO₂, a physical simulation experiment device for CO₂ non-miscible flooding production manner is designed. The device adopts two displacement schemes, gas-displacing water and gas-displacing oil, it mainly studies the immiscible gas flooding mechanism and oil displacement characteristics based on factors such as formation dip angle, gas injection position, and gas injection rate. It can provide a more accurate development simulation for the actual field application. By studying the variation law of crude oil viscosity and start-up pressure gradient, the characterization method of seepage resistance gradient affected by these two factors in the seepage process is proposed. The field test is carried out for the natural core of the S oilfield, and the seepage resistance is described more accurately. The results show that the advancing front of the gas drive is an arc, and the advancing speed of the gas drive oil front is slower than that of gas drive water; the greater the dip angle, the higher the displacement efficiency; the higher the gas injection rate is, the higher the early recovery rate is, and the lower the later recovery rate is; oil displacement efficiency is lower than water displacement efficiency; taking the actual core of S oilfield as an example, the mathematical representation method of core start-up pressure gradient in low permeability reservoir is established.

CO ₂驱可显着提高采收率，有效回收原油，具有节能减排的优点。目前国内CO ₂驱渗流实验研究大多是实际油藏现场试验或油藏数值模拟器模拟。虽然有针对性，但推广效果不佳。对于渗流阻力的表征，目前对储层内综合作用引起的渗流阻力变化规律的研究较少。_{针对这一问题，基于CO 2}机理，设计了CO ₂非混相驱开采方式物理模拟实验装置。该装置采用气驱水和气驱油两种驱油方案，主要根据地层倾角、注气位置、注气量等因素研究非混相气驱机理和驱油特征。可以为实际现场应用提供更加准确的开发模拟。通过研究原油粘度和启动压力梯度的变化规律，提出了渗流过程中受这两个因素影响的渗流阻力梯度表征方法。对S油田天然岩心进行了现场试验，更准确地描述了渗流阻力。结果表明，气驱推进前沿呈弧形，气驱油前沿推进速度慢于气驱水推进速度；倾角越大，驱油效率越高；注气量越大，早期采收率越高，后期采收率越低；驱油效率低于驱水效率；以S油田实际岩心为例，建立了低渗透油藏岩心启动压力梯度的数学表示方法。