低渗透非均质油藏二氧化碳非混相驱窜逸控制实验  

Experiments of gas channeling control during CO_2 immiscible flooding in low permeability reservoirs with heterogeneity

作　　者：郝宏达[1,2,3] 侯吉瑞[1,2,3] 赵凤兰[1,2,3] 侯利斌[1,2,3] 王志兴[1,2,3] 宋兆杰[1,2,3] 

机构地区：[1]中国石油大学(北京)提高采收率研究院,北京102249 [2]中国石油三次采油重点实验室低渗油田提高采收率应用基础理论研究室,北京102249 [3]石油工程教育部重点实验室,北京102249

出　　处：《油气地质与采收率》2016年第3期95-100,115,共7页Petroleum Geology and Recovery Efficiency

基　　金：国家科技支撑计划"陕北煤化工CO2捕集;埋存与提高采收率技术示范"(2012BAC26B00)

摘　　要：低渗透油藏普遍存在非均质性严重、裂缝发育等特点,导致二氧化碳驱油过程中会发生不同程度的气窜现象。为了研究非均质性及裂缝对二氧化碳驱油效果的影响,建立均质岩心模型、不同渗透率级差的人造非均质模型、高渗透气窜通道模型及裂缝模型4种室内实验模型,用以模拟低渗透储层的非均质性及裂缝发育。利用4种模型依次开展水驱和二氧化碳连续气驱实验,并针对不同类型的岩心模型采取相应的封窜体系对二氧化碳实施气窜封堵。实验结果表明,二氧化碳连续气驱的采出程度与渗透率级差呈幂函数下降趋势,岩心非均质性越强,气体窜逸现象越严重,气驱效果越差。针对不同非均质级别的岩心,可采用不同的封窜体系实现二氧化碳的窜逸控制。其中,乙二胺体系可用于封堵渗透率级差小于等于100的非均质模型的高渗透层,改性淀粉凝胶与乙二胺体系可用于封堵岩心内渗透率级差大于100的高渗透气窜通道以及裂缝。Fractures and severe heterogeneity commonly exist in the low permeability reservoirs,which will cause varyingdegrees of gas channeling phenomena during CO2 flooding. In order to study the effect of heterogeneity and fractures on CO2flooding efficiency,four experimental models of homogeneous model,heterogeneous model with various permeability ratios,high-capacity gas channeling model and fracture model were built in the laboratory to simulate the heterogeneity and fracture of the low permeability reservoirs. Waterflood and continuous CO2 flooding were conducted firstly,followed by gaschanneling control experiments using different gas channeling control systems in different types of experimental models correspondingly. Experimental results showed that the oil recovery of continuous CO2 flooding had a power function negativecorrelation with permeability ratios and the gas channeling phenomena became more severe as the increase of heterogeneity,resulting in the poor displacement efficiency of CO2. Gas channeling control can be achieved using different gas channeling control systems in different types of experimental models. The gas channeling control in heterogeneous models withthe permeability ratio of less or equal to 100 can be achieved by ethylenediamine system plugging high permeability layers,while gas channeling control in high-capacity gas channels and fracture can be achieved by modified starch gel and ethylenediamine.

关 键 词：低渗透油藏 二氧化碳非混相驱 非均质性封窜 波及体积 

分 类 号：TE357.42[石油与天然气工程—油气田开发工程]