低渗透非均质油藏空气泡沫驱替注入参数优化实验

Experiment on Injection Parameter Optimization for Air Foam Flooding in Low-permeability Heterogeneous Reservoir

针对低渗透非均质油藏空气泡沫驱过程中不同渗透率储层注入参数优化困难的问题,以安塞油田长63组天然岩心为例,采用一维岩心流动实验装置开展空气泡沫驱注入参数优化实验,对气液比、泡沫段塞体积、注入压力、注入速率和注入时机进行优化,获得最佳注入参数,并分析不同渗透率储层空气泡沫驱注入参数优化规律。结果表明:同一组岩心内,随着气液比、泡沫段塞体积、注入压力和注入速率增加,采出程度不断提高,当这些注入参数达到一定程度后,采出程度增幅减小或下降,各注入参数均存在最优值;不同注入参数对采出程度的影响很大,对渗透率较低的储层尤为敏感;渗透率与最优注入气液比、注入体积、注入压力、注入速率均具有较好的指数递减关系,低含水时注入空气泡沫能够获得更高的采收率。该研究结果为低渗透油藏空气泡沫驱分区分层精细化注入提供了理论依据。

To address the difficulty of optimizing the injection parameters of different permeability reservoirs in the process of air foam flooding in low-permeability heterogeneous reservoir,in a case study of natural core from Change 63 Formation in Ansai Oilfield,experiments on injection parameter optimization for air foam flooding were performed with one-dimensional core flow experimental equipment to optimize the gas-liquid ratio,foam slug volume,injection pressure,injection rate and injection time to obtain the best injection parameters,and analyze the optimization law of injection parameters for air foam flooding in different permeability reservoirs.The results showed that with the increase of gas-liquid ratio,foam slug volume,injection pressure and injection rate,the recovery percent of the same group of cores increased,and when the injection parameters reached a certain level,the recovery percent increment increased or decreased and there was an optimal value for each injection parameter;different injection parameters greatly affected the recovery percent,especially sensitive to the reservoirs with low permeability;there was a good exponential decreasing relationship between the permeability and the optimal injection gas-liquid ratio,injection volume,injection pressure and injection rate,and air foam injection at low water cut resulted in a recovery efficiency.The study results provide a theoretical basis for regional layered and fine injection of air foam flooding in low-permeability reservoir.