超低渗透油藏CO2驱注入参数优化的实验研究

摘要

CO2flooding is one of the effective methods to enhance recovery in ultra-low permeability reservoir. However,the current understanding of the mechanism of CO2 flooding in ultra-low permeability reservoirs is not clear.For the contradictions of water injection during development process in a western ultra-low permeability reser-voir,study the adaptability of CO2 flooding in the reservoir through physical simulation experiment and optimize the injection method and injection parameter for the low permeability reservoir by comparing the different injection methods and injection parameters impact on oil displacement efficiency.The results of research shows,for the ultra-low permeability fractured reservoirs,cyclic gas injection is best,and when injected slug is 0.06 PV,gas injection and soak time ratio is 1:2 can effectively delay the gas channeling and improve the overall effect of flooding.The research results provide guidance for gas injection in low permeability reservoir field development.%CO2驱是提高超低渗油藏采收率的有效方法之一,然而,目前对CO2在超低渗油藏中的驱油机理认识还不完善.针对西部某超低渗透油藏开发过程中注水矛盾问题,通过物理模拟实验,研究了CO2驱对该超低渗透油藏的适应性,并通过对比不同的CO2注入方式和注入参数对驱油效率的影响规律,优选出超低渗透油藏CO2驱最佳注入参数.实验结果表明:对该超低渗透裂缝性油藏,周期注气方式下驱油效果最佳,且当注入段塞为0.06 PV,注气与焖井时间比为1:2时延缓气窜的效果最好,驱油效率达到60%以上.研究结果为该类型超低渗油藏现场注气开发设计提供指导作用.