本文通过在实验室中进行了油藏条件下相态特性和三次气驱的实验、研究了烃类注剂成份和压力对驱油效率的影响。在较低富化程度或低压下会使注入剂流度降低和降低采收率。然而，对于与油进行了多次接触混相的气体注剂。其驱替效率则较高。实验表明注近混相烃气的方法很有希望，而且在油田中对原驱油效率和近混相气驱效率可以交替进行。 In this paper, the effects of hydrocarbon composition and pressure on flooding efficiency were studied by conducting experiments on phase behavior and gas displacement under reservoir conditions in the laboratory. At lower levels of enrichment or at lower pressures, the injector fluidity is reduced and the oil recovery is reduced. However, for gas injections that have been mixed with oil for multiple contact phases. Its displacement efficiency is higher. Experiments show that the method of near-mixed hydrocarbon gas is very promising, and the efficiency of the original flooding oil and the gas-driven near-miscible gas flooding can be alternated in the oilfield.