为有效解决S358高凝油藏注气难度大、压裂后气驱流度比过大容易气窜导致驱油效率低的问题,开展了室内注气相态及长岩心驱替机理实验。通过地层条件下高凝油注CO₂、干气、烟道气、减氧空气（N₂ 90 %+O₂ 10 %）PVT相态实验,分析了4种注入气与高凝油接触的增溶膨胀、降黏、降低界面张力等特性机理,优选了CO₂作为注入气。通过5组不同复合方式的高温高压长岩心驱替实验,评价了CO₂复合驱油防窜提采效果。实验结果表明,CO₂+弱凝胶、CO₂+泡沫的驱替效果最好,最终驱油效率分别为70.101 %、68.212 %。研究结果说明,CO₂复合驱段塞的注入使得驱替阻力增大,导致裂缝导流能力降低,对改善微观波及体积起到关键性作用。其中,CO₂+弱凝胶、CO₂+泡沫的驱替方式提采效果最佳,研究结果可为该区块高凝油的高效开发提供实验基础。

In order to effectively solve the problems of difficult gas injection in S358 high pour-point reservoir and low oil displacement efficiency caused by gas channeling due to high mobility ratio of gas flooding after fracturing, laboratory experiments of gas injection phase and long core displacement mechanism have been carried out. Through the PVT phase state experiment of the high pour-point oil injected by CO₂, dry gas, flue gas, and oxygen-reduced air（N₂ 90 %+O₂ 10 %）under the formation conditions, the characteristic mechanisms of the above four injection gas such as the solubilization expansion, viscosity reduction and tension reduction have been analyzed. CO₂ is preferred as the injection gas. Through five groups of high temperature and high pressure long core flooding experiments with different combination methods, the effect of CO₂ combination flooding on channeling prevention and extraction is evaluated. The experimental results show that the displacement effects of both CO₂+weak gel and CO₂+foam are the best two, and the final displacement efficiency is 70.101 % and 68.212 % respectively. The research results show that the injection of CO₂ combined flooding slug increases the displacement resistance and reduces the fracture conductivity, which plays a key role in improving the microscopic sweep volume. Among them, both the CO₂+weak gel and CO₂+foam displacement methods have the best extraction effects. The research results can provide an experimental basis for the efficient development of high pour point oil in this block.