裂缝储层空气泡沫驱注入参数优化实验

为提高裂缝性油藏空气泡沫驱的采收率,以王窑中西部地区长₆段储层为研究对象,开展前期水驱、空气泡沫驱、后续水驱实验,优化气液体积比、泡沫段塞体积、注入压力、注入速率和注入时机等参数。结果表明:泡沫注入岩心后,含水率迅速降低,采出程度迅速提高,裂缝岩心相对基质岩心封堵更快,但封堵效果较差;注入空气泡沫时间越早,最终采收率越高;最优气液体积比、泡沫段塞体积、注入压力、注入速率与岩心渗透率呈负相关,但因裂缝渗透率较大,渗透率变化对最佳注入参数的敏感性较弱。该研究结果可为低渗透油藏裂缝性储层空气泡沫驱精细化注入提供重要的理论依据。

Experiment on Optimization of Injection Parameters for Air-foam Flooding in Fractured Reservoirs

In order to improve the recovery efficiency of air-foam injection flooding in fractured reservoirs, experiments of early-stage water flooding, air-foam flooding and subsequent water flooding were conducted in Chang6 Member reservoirs in the west-central area of Wangyao Block to optimize gas-liquid volume ratio, foam slug volume, injection pressure, injection rate and injection time. The results showed that, after the foam was injected into the core, the water content was decreased rapidly, the recovery percent was increased rapidly, the fractured core was plugged faster than the matrix core, but the plugging effect was poor; the earlier the air and foam were injected, the higher the final recovery efficiency; the optimal gas-liquid volume ratio, foam slug volume, injection pressure and injection rate were negatively correlated with the core permeability, and the permeability change was less sensitive to the optimal injection parameters due to high fracture permeability. The results of the study provide an important theoretical basis for fine injection of air-foam flooding in low-permeability fractured reservoirs.