平面非均质油藏水气交替驱提高采收率室内实验研究

水气交替(WAG)驱提高采收率技术和应用研究在我国处于起步阶段。借助室内驱替实验,明确了WAG驱在平面非均质油藏的适应性及其提高采收率的作用机理。将并联式填砂管替代常规岩心夹持器,进一步减弱了长岩心驱替产生的末端效应和应力敏感现象,模拟真实的平面非均质油藏条件。实验结果表明,WAG驱可减缓气窜,改善吸水剖面。注入N2可加强三相分子之间的交换、扩散、渗吸作用。对于非均质性严重的储层,水气交替注入后水驱封堵高渗带,气驱驱扫小孔隙,帮助形成稳定的驱替前缘,提高低渗储层的驱油效率。

Laboratory Experimental Study on Increasing Oil Recovery by Plane Heterogeneous Reservoir by Alternating Water and Gas

The technologies and applications of WAG flooding recovery are in the initial stage in our country. In this paper, with the help of indoor flooding experiments, the adaptability of WAG flooding to planar heterogeneous reservoirs and its mechanism of enhanced oil recovery are clarified. Replacing the conventional core-holder with the parallel filled sand tube further weakens the end-effect and stress-sensitive phenomenon caused by long core flooding and simulates the real planar heterogeneous reservoir conditions. Experimental results show that WAG flooding can slow gas channeling and improve water absorption profile. N2 can be injected to enhance the exchange between the three-phase molecules, diffusion, imbibition. For reservoirs with high heterogeneity, water-gas injection after water-gas injection alternately seals the high permeability zone and drives the small pores by gas drive to help form a stable displacement front and improve the oil displacement efficiency of the low-permeability reservoir.