摘要
对具有非均质性强,原油混相压力高,储层亏空严重等特点的低渗油藏,CO2非混相驱是重要的提高采收率技术。首先通过室内试验开展了原油注CO2膨胀实验,并测定了CO2-原油最小混相压力,然后应用数值模拟分别研究了非混相驱界面张力及油气组分沿程分布的动态变化,进而从恢复储层能量和提高驱油效率两个角度揭示了CO2非混相驱的主控机理,最后以低渗岩性M油藏为对象,基于三维精细地质模型,通过数值模拟优化了储层压力、注气量、注气速度及关井气油比等关键参数,制定了最优技术政策,经矿场应用取得良好开发效果。研究表明,对低渗油藏CO2非混相驱,恢复储层能量的主控机理为注气溶解膨胀原油,而提升驱油效率的主控机理为溶解膨胀原油、降低界面张力及蒸发抽提轻质组分。研究成果可为同类型油藏CO2非混相驱的方案制定及现场应用提供参考。
CO2 immiscible flooding is a very important technology for low permeability reservoirs with strong heterogeneity,high miscibility pressure of crude oil or severe reservoir voidage.Firstly,the expansion experiments and MMP test of CO2 injection are carried out,and the IFT and mole content of oil and gas phase of each block are tested by numerical simulation.And then,the dominant mechanism of CO2 injection to recover reservoir energy and improve oil displacement efficiency in low permeability reservoir are revealed.Therefore,taking M Block with low-permeability as the research object,and based on 3D fine geological modeling,the numerical simulation is applied to optimize reservoir pressure,gas injection volume,gas injection velocity,shut-in gas-oil ratio and other parameters,and the optimal technical policy is formulated.Preferable recovery performance is obtained through field application.The results show that for the CO2 immiscible flooding technology in low permeability reservoirs,dissolving and expanding oil phase by gas injection are the dominant mechanism for both recovering reservoir energy and improving oil displacement efficiency,besides,the latter still need to reduce the IFT and evaporate and extract the light components.This study provides a reference for the formulation of CO2 immiscible continuous flooding scheme in other reservoirs of the same type.
作者
金忠康
王智林
毛超琪
JIN Zhongkang;WANG Zhilin;MAO Chaoqi(NO.2 Oil Production Company of Jiangsu Oilfield Company,Jinhu,Jiangsu 211600,China;Research Institute of Exploration and Development of Jiangsu Oilfield Company,Yangzhou,Jiangsu 225009,China)
出处
《油气藏评价与开发》
CSCD
2020年第3期68-74,共7页
Petroleum Reservoir Evaluation and Development
基金
中国石化科技项目计划“苏北复杂断块低渗油藏注CO2技术及应用”(P16050)
江苏省博士后科研资助计划(A类)“江苏油田复杂断块油藏CO2气顶与人工边水组合驱替技术研究”(1801015A)。
关键词
低渗透油藏
恢复储层能量
主控增油机理
技术政策优化
矿场试验
low permeability reservoir
reservoir energy recovery
dominant EOR mechanisms
parameter optimization
field application
