摘要
对于低渗透油藏,油水界面张力、岩石润湿性和孔喉比是影响产量和采收率的重要因素,而润湿指数和润湿角通过毛管数与驱油效率有直接的定量关系。该文提出了一个关联着界面张力、润湿性和孔喉比的修正毛管数概念,建立了基于Amott润湿指数与USBM指数的润湿角表征方法,继而推导出低渗透储层毛管数表达式,并通过岩心实验确定出其与残余油饱和度的关系。以此为基础给出不同界面张力与润湿情况下的相对渗透率曲线、驱油效率和注入能力的计算公式,揭示了各种油藏物理参数之间的关联性,为优化低渗透油层化学驱改变界面张力、润湿性控制参数,进而为提高驱油效率和采收率提供了理论依据。
For low-permeability reservoirs,interfacial tension,rock wettability and pore-throat ratio are important factors affecting production and recovery. Wettability index and wetting angle have a direct quantitative relationship with oil displacement efficiency. This paper presents a concept of modified capillary number associated with interfacial tension,rock wettability and pore-throat ratio,and establishes a wetting angle characterization method of low-permeability reservoir based on Amott wettability index and USBM index. We also derive a capillary number expression for low-permeability reservoirs and determine the relationship with residual oil saturation through core test. Based on this,the calculation formulas of a relative permeability curve,oil displacement efficiency and injection ability are given for different conditions of interfacial tension and wetting angle,which reveals the relationship between reservoir physical characteristics. The study provides a theoretical basis for optimizing chemical flooding,changing interfacial tension and wettability controlling parameters in low-permeability reservoir,and further improves oil displacement efficiency and recovery.
出处
《石油实验地质》
CAS
CSCD
北大核心
2015年第2期129-133,149,共6页
Petroleum Geology & Experiment
基金
中国博士后科学基金"低渗透油藏CO2驱替特征及优化开采研究"(2010047050)
国家自然科学基金重点项目"低渗透油层提高驱油效率的机理研究"(50634020)
国家自然科学基金青年科学基金"微观孔隙内原油活化条件的动力学机理研究"(51104030)共同资助
关键词
毛管数
润湿角
界面张力
相对渗透率
驱油效率
低渗透储层
capillary number
wetting angle
interfacial tension
relative permeability
displacement efficiency
low-permeability reservoir
