板桥-合水地区长63储层成岩相孔隙结构特征及优质储层分布

利用铸体薄片、扫描电镜、常规压汞、恒速压汞及相渗等资料,研究了板桥-合水地区长6₃储层成岩相类型及其微观孔隙结构特征,总结了不同成岩相的测井响应特征,确定了纵向及平面分布规律。结果表明优质成岩相的展布受沉积相、成岩作用与孔隙结构共同控制,尤其是喉道分布才是控制砂岩储层渗透性的主要因素。水云母胶结-残余粒间孔相和水云母胶结-长石溶蚀相储层主要分布于半深湖相重力流复合水道浊流沉积中,细-微细喉道发育,孔喉连通性好,渗流能力最好,油水呈相对均匀的渗流,孔隙内的油气极易通过喉道被开采出来;绿泥石胶结相、水云母胶结弱溶蚀相储层位于分支水道边缘,呈孤岛状分布,孔喉半径小但分布均匀,渗流能力中等-差;碳酸盐胶结相、碳酸盐+水云母胶结相储层主要发育在分支水道间,孔隙结构发育程度差,喉道细小且孔喉连通性差,富集于孔隙中的油气难以通过小喉道,采收率低。

Micro-pore Structure of Diagenetic Facies of Chang 63 Reservoir and Distribution of High Quality Reservoir in Banqiao-Heshui Area

Types of diagenetic facies and micro-pore structure characteristics of sandstone components of Chang 6₃ reservoir in Banqiao-Heshui area are systematically studied according to thin section, scanning electron microscope, mercury injection, constant-rate mercury penetration and relative permeability data. Logging response stencil is also established. Moreover, diagenetic facies parallel and planar distribution have been studied. The results show that relationship between quality of diagenetic facies controlled by sedimentary facies, diagenesis and pore structure, especially throat distribution, which is the major factor controlling the reservoir permeability. Reservoirs belonging to hydromica cementation-residual intergranular pore facies and hydromica cementation-feldspar dissolution facies, in which fine or micro-fine throat develops, pore connectivity is good, show the best flow ability and a relatively uniform oil-water percolation. These facies located in flow composite channel turbidite deposition in semi deep lake facies of gravity and oil within pores is easily mined through the throat. Pore throat radius of chlorite cementation facies and hydromica weak ementation dissolution facies is small but uniform distribution, besides this kind of reservoir distributed in the branching channel margin and seepage permeability is middle to poor. Carbonate cementation facies and carbonate+hydromica cementation facies with the worst pore structure mainly developed in the branch between the canal. Due to fine throat and poor pore connectivity, oil enrichment in pore is difficult to pass through fine throat, and recovery ratio of these two kinds of diagenetic facies is very low.