弱碱三元体系对孔隙结构影响研究

ASP三元复合驱能扩大波及体积并且提高驱油效率,同时能极大的降低表面活性剂用量,使具有极其良好的技术经济可行性。通过常规压汞实验及扫描电镜实验分析研究了岩心在弱碱三元驱后的孔隙结构特征,对比分析了弱碱三元体系渗流前后岩心的孔隙结构特征变化。对其结果分析可知,由于弱碱三元体系对储层岩石有一定的溶蚀作用,当弱碱三元体系进入小孔道时,对小孔道的溶蚀导致小孔道半径变大,减少小孔道的数量,增多大孔道的数量,从而略微增大整体岩心的渗透率。弱碱三元复合驱前岩石致密,孔隙较小且比较均匀。弱碱三元复合驱后,出现斑驳状凸起,孔隙发育比较明显,岩石上有可动碎屑附着。碱的浓度越高,三元体系对岩心的溶蚀作用强烈,对岩心伤害程度更大。

Influence of Weak Alkali ASP System on the Pore Structure

ASP flooding can expand the swept volume and improve oil displacement efficiency,at the same time it can greatly reduce the surface activity agent dosage,so it has very good technical and economic feasibility.In this paper,based on the conventional mercury injection experiment and scanning electron microscopy analysis,pore structure characteristics of the core after weak alkali ASP flooding were studied,the change of core pore structure before and after weak alkali ASP flooding was compared and analyzed.The results show that,the weak alkali ASP system has certain solubility to reservoir rocks;when the weak base ASP system flows into the small hole,radius of the small holes will increase due to the corrosion;the number of small hole decreases,while the number of large channel increases,so the overall permeability of cores slightly increases.Before weak alkali ASP flooding,the rock is density.pore is smaller and more uniform.After weak alkali ASP flooding,mottled shape bulges appear,pore growth is more noticeable,there is movable clastic sediment attached to the rock.The higher the concentration of alkali,the stronger the ternary system dissolution effect is,and the bigger the core damage degree is.