裂缝性油藏注气多相流动机理与气窜数学模型分析  

Mathematical model analysis of multiphase flow and gas channeling of in gas injection fractured oil reservoirs

作　　者：王付勇[1] 程辉 侯贤沐 WANG Fuyong;CHENG Hui;HOU Xianmu(Unconventional Petroleum Research Institute, China University of Petroleum, Beijing 102249,China)

机构地区：[1]中国石油大学(北京)非常规油气科学技术研究院,北京102249

出　　处：《非常规油气》2022年第4期58-64,122,共8页Unconventional Oil & Gas

基　　金：国家自然科学基金项目“表面活性剂在致密油藏裂缝-微纳米孔隙中的多尺度渗吸驱油机理研究”(51874320)。

摘　　要：气驱是一种重要的提高油藏采收率的方法,然而注入气会沿着油藏中的裂缝发生气窜,影响气驱效果。在裂缝和基质中,对注气过程中油气水三相的运移过程进行力学分析,分别构建了适用于裂缝和基质的油气水三相运移力学模型,推导得到了在裂缝和基质中的油气水三相运移速度和位移表达式。基于所构建的力学模型,分别研究了在裂缝和基质中不同的注入条件、油藏和流体物性对油气水三相的运移规律的影响。研究结果表明裂缝与基质渗透率极差是气窜的主控因素。当裂缝渗透率与基质渗透率存在较大差异时,在裂缝中油气水三相的运移速度明显快于基质,且裂缝与基质中的运移速度的比值,与裂缝与基质的渗透率极差几乎成正比。油气水三相的运移速度随着注气压力梯度的增加而增加,随着油水黏度比的增加而减小。裂缝与基质渗透率极差越大,注气压差越大,油水黏度比越小,越容易发生气窜。Gas flooding is an important method to enhance oil recovery.However,injected gas will cause gas channeling along the fractures in the oil reservoir,which will affect the gas flooding effect.The migration processes of oil-gas-water three phases in the single facture and pore during the process of gas injection are analyzed,and the mechanical models for oil-gas-water three phases flow in the fracture and matrix are developed,respectively.The expressions of flow velocity and displacement of three phases are derived.Based on the developed mechanical model,the effects of different gas injection conditions,properties of reservoir and fluid on three-phase flow are studied.The research results show that the permeability ratio between fracture and matrix is the main controlling factor of gas channeling.When there is a big difference between the fracture permeability and the matrix permeability,the flow velocity of three phase in the fracture is obviously faster than that in the matrix.The ratio of flow velocity in the fracture to that in matrix is almost proportional to the permeability ratio between fracture and matrix.The three-phase flow velocity increases with the increase of gas injection pressure gradient,and decreases with the increase of oil-water viscosity ratio.The greater the permeability ratio between the fracture and the matrix,the greater the injection pressure difference,the smaller the oil-water viscosity ratio,and the easier gas channeling occurs.

关 键 词：裂缝 注气 气窜 多相流动 力学分析 

分 类 号：TE122.14[石油与天然气工程—油气勘探]