强碱三元体系对岩心渗透率的影响规律  

Effect of strong-alkali ASP system on core permeability

作　　者：王杰祥[1] 马涛[1] 马文国[2] 于春野 秦昊良 WANG Jiexiang;MA Tao;MA Wenguo;YU Chunye;QIN Haoliang(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao City,Shandong Province,266580,China;Key Laboratory of Enhanced Oil and Gas Recovery,Ministry of Education,Northeast Petroleum University,Daqing City,Heilongjiang Province,163318,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]东北石油大学,提高油气采收率教育部重点实验室,黑龙江大庆163318

出　　处：《油气地质与采收率》2020年第3期79-84,共6页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项“高温高盐油田化学驱提高采收率技术”(2016ZX05011-003)。

摘　　要：强碱三元体系注入油层后,碱与矿物组分发生化学反应及物理变化。强碱溶蚀岩石表面,溶蚀产物及黏土颗粒在油层渗流通道上运移沉淀,对渗流造成较大伤害。以A油田为研究对象,从碱对矿物组分的溶蚀性入手,通过渗流实验,借助扫描电镜及能谱分析仪等,分析了强碱对储层的伤害机理及溶蚀后的矿物组分变化,进而研究对岩心渗流能力的影响。岩心渗流实验结果表明,强碱三元体系长时间驱替后,注入压力上升约140 kPa,岩心渗透率平均下降18%。岩心原始孔隙结构在强碱的溶蚀和渗流冲刷下严重破坏,高岭石和蒙脱石等晶体结构被破坏。长时间驱替后,碱溶反应生成的沉淀物及脱落的黏土颗粒运移堵塞和附着在孔喉通道壁面,使岩心的渗流能力下降。扫描电镜结果表明,驱替前、后岩石矿物表面特征发生变化,颗粒运移,元素含量也随之变化,进一步验证了强碱三元体系对岩心渗透率的影响规律。After the strong-alkali ASP system is injected into the reservoirs,the chemical reactions and physical changes take place between the alkali and mineral composition.The strong alkali dissolves the rock surface,and the dissolution products and clay particles migrate and precipitate on the flow channel of the reservoir,which causes great damage to the fluid flow.Taking Block A of Daqing Oilfield as a case,through percolation experiment by using the scanning electron microscope(SEM)and energy spectrum analysis,the damage mechanism of the strong alkali to formation and the change of mineral composition after dissolution are analyzed based on the dissolution of alkali to mineral composition,and then the influence on the core percolation ability is discussed.The core percolation experiment shows that the injection pressure increases about 140 kPa and the core permeability decreases about 18%after the long-term displacement using strong-alkali ASP system.Due to the dissolution caused by the strong alkali and percolation erosion,the original pore structure of the core is strongly destroyed,and the crystal structures of the kaolinite and montmorillonite etc.are destroyed also.After longtime displacement,the sediment formed after the alkali solution reaction and the clay particles detached migrate and stick to the surface of the pore throat channel,which causes the decrease of the core permeability.The results of SEM show that the surface characteristics of the rock minerals change before and after displacement,and the element content changes with the particle migration,which further verifies the effect of the strong-alkali ASP system on core permeability.

关 键 词：扫描电镜 矿物组分 渗透率 强碱 三元体系 储层伤害 

分 类 号：TE357.46[石油与天然气工程—油气田开发工程]