义北油田大43区块沙二段沉积微相对储层物性的控制作用

Control effect of sedimentary microfacies on reservoir property of the 2nd member of Shahejie Formation in Yibei Oilfield D43 block

义北油田大43区块沙二段是区内重要的含油层,沉积微相控制着砂岩的展布及物性的变化,同时又控制着区块油藏的分布,因而对该区沙二段沉积微相的综合研究具有重要的意义。通过对大43地区岩心和测井资料的分析,建立了沙二段地层格架和单井相模式。研究表明,该区沙二段沉积相主要为滨浅湖滩坝沉积体系,包括滩亚相和坝亚相2种亚相,进一步可分为坝主体、坝侧缘、滩席、碳酸盐岩滩和滨浅湖泥5种重要沉积微相。该区优势相为坝主体和碳酸盐岩滩沉积微相,其控制了优质储层的形成与展布。并在前述研究基础上优选出3个有利区:D43-324至D43-332井区域、D43-393井区域、D43-357井区域。

The 2nd member of the Shahejie Formation is an important oil bearing reservoir in Yibei Oil Field Da 43 block.The distribution and physical properties of sandstone are controlled by sedimentary microfacies,and the porosity and permeability of sandstones are important to the oil accumulation in this area.Therefore,it is of great significance to study the sedimentary microfacies of the 2nd member of the Shahejie Formation in this area.The stratigraphic framework and the single well microfacies pattern of the 2nd member of the Shahejie Formation in D43 area is established by researching the core and logging data.Studies have shown that,the sedimentary facies of the 2nd member of Shahejie Formation in this area are mainly the shallow lake depositional system,including the shore shallow lake beach and dam facies.And contain five main kinds of sedimentary microfacies,such as dam body,dam side edge,carbonate beach,shallow lake mud,beach mat.It is found that the two kinds of sedimentary microfacies of dam body and carbonate beach are the dominant phases,which control the formation and distribution of high quality sand bodies.On this basis,three favorable areas are selected：D43-324 to D43-332 area,D43-393 area and D43-357 area.