砂岩油藏CO2驱替过程中溶蚀作用对储层物性的影响  

Effect of dissolution on physical properties of sandstone reservoirs during CO2 flooding

作　　者：袁舟 廖新维[1] 赵晓亮[1] 陈志明[1] YUAN Zhou;LIAO Xinwei;ZHAO Xiaoliang;CHEN Zhiming(College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing City,102200,China)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102200

出　　处：《油气地质与采收率》2020年第5期97-104,共8页Petroleum Geology and Recovery Efficiency

摘　　要：在CO2驱替过程中,CO2溶于水中形成的酸性流体会对砂岩油藏发生溶蚀作用,从而改变油藏储层的物性,极大影响原油采收率。因此,进行砂岩油藏CO2驱静态浸泡实验与动态驱替实验,定量研究不同温度和压力条件下溶蚀作用对储层物性的影响。实验结果表明,CO2浸泡和驱替过程中溶蚀作用明显,随温度、压力的升高,孔隙度和渗透率呈指数型增长。通过实验数据,得到温度、压力与孔隙度变化率和渗透率变化率关系的数学表征方程。借助数学表征方程,对长庆油田H3区块进行数值模拟研究,结果表明,研究区块储层整体发生溶蚀作用,且注气井区域溶蚀程度更高。考虑溶蚀作用的原油采收率为26.08%,不考虑溶蚀作用的原油采收率为21.03%,原油采收率提高了5.05%。The acidic fluid formed by CO2 dissolved in water could dissolve sandstone in the process of CO2 flooding in reservoirs.The dissolution could change the physical properties of the reservoirs and obviously affect the oil recovery.Therefore,the static immersion experiment and dynamic displacement experiment of CO2 flooding in sandstone reservoirs were carried out to quantitatively study the influence of dissolution on the physical properties of the reservoirs under different temperature and pressure conditions.The experimental results show that the dissolution effect is obvious in the process of CO2 immersion and flooding.The porosity and permeability increase with the increase of temperature and pressure exponentially.The mathematical expression equations of the relationships between the temperature,pressure and porosity change rate and permeability change rate were obtained based on the experimental data.The numerical simulation study was carried out on Block H3 of Changqing Oilfield with the aid of mathematical equations.The results showed that the dissolution in the overall reservoir of the study area occurred,and the dissolution degree in the injection well area was higher.The oil recovery considering dissolution is 26.08%,but the oil recovery without considering dissolution is 21.03%.The enhanced oil recovery(EOR)is 5.05%.

关 键 词：CO2驱 溶蚀作用 储层物性 数学表征方程 提高采收率 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]