塔河地区缝洞型油藏注气替油效果实验

Experiment on the Effect of Gas Injection and Oil Replacement in Fracture-cavity Reservoirs in Tahe Area

缝洞型油藏储层具有非均质性严重、流体分布复杂、缝洞本身的多尺度性和连通多样性的特点,随着现场开发的不断深入,只采用注水措施难以保证需求,还需从机理入手提高原油采收率和改善开发效果。因此,结合单井物模注气替油实验,研究了底水和注气方式以及含油体积对注气效果的影响。结果表明:底水充足时可借助底水能量驱油,在注气轮次相同时底水充足油藏注气采收率高于无底水;针对底水油藏采用单纯注气、水气交替及水气混注3种方式,在底水充足的情况下,纯注气吞吐方式效果明显好于气水混合注入方式和气水段塞注入方式;在相同的注气吞吐条件下,含油体积大的油藏注气效果更加明显。

Fractured vuggy reservoir has the characteristics of serious heterogeneity,complex fluid distribution,multi-scale and connectivity diversity.With the continuous deepening of field development,it is difficult to ensure the demand only by using water injection measures.It is also necessary to start from the mechanism to improve oil recovery and development effect.Therefore,the effect of bottom water,gas injection mode and oil-bearing volume on gas injection effect was studied in combination with single well physical model experiment.The results showed that oil displacement was achieved with the help of bottom water energy when the bottom water was sufficient,and the gas injection recovery of the reservoir with sufficient bottom water was higher than that of the reservoir without bottom water when the gas injection turns were the same;for the reservoir with bottom water,three methods were adopted,namely,simple gas injection,water gas alternate injection and water gas mixed injection.Under the condition of sufficient bottom water,the effect of pure gas injection huff and puff was obviously better than that of gas-water mixed injection and gas-water slug injection;Under the same huff-puff condition,the effect of gas injection was more obvious in the reservoir with large oil volume.