三肇地区葡萄花油层微观孔隙结构及剩余油分布特征

Microscopic Pore Structure and Remaining Oil Distribution Characteristics of Putaohua Oil Layer in Sanzhao Area

为搞清微观剩余油分布,首次利用压汞资料、岩心薄片、扫描电镜、数字岩心、油水驱替实验等资料和技术,对三肇地区葡萄花油层微观孔隙结构及微观剩余油分布特征进行系统研究。构建数字岩心及孔隙网络模型,将孔隙结构类型划分为五种,其中以Ⅱ、Ⅲ、Ⅳ类孔隙结构为主,微观非均质性严重。研究不同孔隙结构二维和三维微观剩余油分布,平面上微观剩余油Ⅰ、Ⅱ类储层主要为簇状和角隅状,Ⅲ类储层以喉道状、角隅状为主;微观剩余油三维空间展布,初期以网络状为主,随着注水倍数增加向多孔状过渡,后期多孔状向孤立状和薄膜状转变,最终以多孔状和孤立状为主。剩余油分布受孔隙结构控制,微观孔隙结构发育直接影响储层含油饱和度。关于措施调整,建议Ⅰ、Ⅱ类储层以调堵、补孔、完善注采关系为主,Ⅲ、Ⅳ、Ⅴ类储层以压裂、细分、加强注水来提高驱油效率。

Microscopic pore structure and remaining oil distribution characteristics of the Putaohua oil layer in the Sanzhao area are systematically studied to clarify the microscopic remaining oil distribution using mercury injection data,core thin sections,scanning electron microscopy,digital core,oil-water displacement experiments,and other data and technologies for the first time.A digital core and pore network model is constructed,and five pore structure types are divided,among which ClassⅡ,Ⅲ,andⅣpore structures are the main ones,with serious microscopic heterogeneity.The two-dimensional and three-dimensional microscopic remaining oil distribution of different pore structures is studied.The microscopic remaining oil of ClassⅠandⅡreservoirs are mainly cluster-shaped and corner-shaped on the plane,while that of ClassⅢreservoirs are mainly throat-shaped and corner-shaped.The three-dimensional spatial distribution of microscopic remaining oil is mainly network-like in the early stage,and porous-like as the pore volume increases,and later changes to isolated-like and film-like,and finally porous and isolated-like.The pore structure controls the remaining oil distribution,and the development of the microscopic pore structure directly affects the oil saturation of the reservoirs.Regarding the adjustment of measures,it is recommended that ClassⅠandⅡreservoirs should focus on profile control and plugging,re-perforating,and improving the injection-production relationship,while ClassⅢ,Ⅳ,andⅤreservoirs should focus on fracturing,subdivision,and enhanced water injection to improve oil displacement efficiency.