埕110块碎屑岩储层物性表生作用分带性研究

埕110块位于济阳坳陷埕东凸起北坡,以位于地层不整合之下的二叠系上石盒子组奎山段含砾岩屑石英砂岩为主要碎屑岩储层。储层物性的发育受不整合面及表生作用的影响明显,表现为随距不整合面距离的增大,在纵向上存在五个具有不同物性发育特征的表生分带。其中渗流带上部由于土壤层的粘土矿物被渗流水携带并沉淀在风化裂缝及粒间孔隙中,而使孔渗性显著降低;渗流带下部淋滤溶蚀对储层改造较强,孔渗性增加;潜流带上部胶结物沉淀占优势,孔渗性降低;潜流带下部及滞流带表生作用逐渐变弱,表生成岩作用对储层物性的影响也逐渐降低。表生作用所形成的最高孔隙度的位置可能位于潜水面附近。

A study on the zoning of hypergenesis of physical properties of clastic reservoir in Cheng 110 block

Cheng 110 block lies in the north slope of Chengdong uplift,Jiyang Depression.The main clastic reservoir in this area is psephitic quartzose sandstone in Kuishan member,upper Shihezi formation of Permian under stratigraphic unconformity.Unconformable surface and hypergenesis can both obviously affect reservoir physi-cal properties,and along with increasing of distance from unconformable surface,five hypergene zones with different growth features of physical properties existed in the vertical.At the upper part of the percolation belt,porosity and permeability decreased greatly for clay mineral in soil was carried by percolation water and deposited in the weathered fractures and intergran-ular pores;at the lower part of the percolation belt,po-rosity and permeability increased for reservoir was re-formed greatly by leaching and corrosion;at the upper part of underwater current belt,porosity and permeabil-ity decreased for dominant cement deposition;at the lower part of the underwater current belt and stagnant belt,hypergenesis became weaker and the effect of epidiagenesis on the reservoir physical properties be-came gradually poor,too.The position with highest po-rosity formed by hypergenesis may locate near underwa-ter level.