油田空气泡沫驱化学分析及提高采收率研究

Chemical Analysis and EOR Research of Air foam Flooding in Oilfield

低渗透油藏的开发主要依赖于储层的自然驱动力和人工注水驱动,但这些驱动方式对于低渗透油藏的开采效率不高,导致采收率较低。空气泡沫驱是一种利用空气和表面活性剂制备的泡沫流体进行驱替的提高采收率技术,具有成本低、效果好、环境友好等优点。基于此,通过长岩心驱替装置进行了空气泡沫段塞驱实验,并与水驱和注空气采油驱替实验进行对比分析。结果表明:泡沫段塞为0.1 PV时,采出程度最高,优于0.2 PV、0.3 PV和0.4 PV的情况,表明0.1 PV泡沫段塞最合理;在泡沫驱阶段,当注入速度由0.1 mL·min^(-1)减至0.05 mL·min^(-1)后,总体采收率和段塞驱阶段的采收率提高幅度都有所提升,表明注入速度与采收率成负相关性;非均质性是低渗透油藏开发效率的主要制约因素,空气泡沫驱能有效实现油藏的封堵调剖。水驱后采用空气泡沫驱能够增加油藏的最终采收率。实验结果可为同类型低渗透油田提高采收率提供借鉴。

The development of low-permeability reservoirs mainly depends on the natural driving force of the reservoir and artificial water injection,but these driving methods are not efficient for the production of low-permeability reservoirs,resulting in low recovery.Air foam flooding is an enhanced oil recovery technology that uses foam fluid prepared by air and surfactants for displacement.It has the advantages of low cost,good effect,and environmental friendliness.Based on this,an air foam slug flooding experiment was carried out with a long core displacement device,and it was compared with water flooding and air injection oil recovery displacement experiments.The experimental results showed that when the foam slug was 0.1 PV,the recovery degree was the highest,better than 0.2 PV,0.3 PV and 0.4 PV,indicating that 0.1 PV foam slug was the most reasonable;Both the overall oil recovery rate and the oil recovery rate in slug flooding stage were improved,indicating that the injection rate and the recovery rate were negatively correlated;Heterogeneity was the main limiting factor for the development efficiency of low permeability reservoirs,and air foam flooding could effectively achieve reservoir plugging and profile control.Using air foam flooding after water flooding can increase the ultimate oil recovery of the reservoir.The experimental results can provide reference for improving oil recovery in the same type of low permeability oilfield.