S77山2^3段储层特征及分类评价

Reservoir Characteristics and Classification Evaluation of the Palaeozoic Shan 2~3 in s77 Formation Uniform graceful

苏里格气田东区北端上古生界山西组山23段是天然气的主力产层之一。储层段主要发育辫状河沉积,其中心滩微相为最有利的沉积相带。通过铸体薄片、储层物性、压汞及扫描电镜等资料对储层特征进行分析,研究结果表明:储层岩石类型以石英砂岩为主,有矿物成熟度高而结构成熟度低的岩石学特点,孔隙类型以粒间溶孔和晶间孔为主,总体物性较差,属于典型的低孔低渗储层。研究区较强的压实作用、胶结作用是形成低孔低渗的主要因素;溶蚀作用改善储层物性起到积极作用。综上分析可将研究区储层段分为4类,其中以Ⅱ类储层较发育。

Shan 23section of Neopaleozoic Shansi group is one of the principal natural gas producing formation in the northern Sulige gas field of eastern area.Braided fluvial deposition mainly develop in the reservoir,among which batture microfacies are the most favorable sedimentary facies zone.Through data analysis of cast slice, reservoir properties, mercury penetration and scanning electron microscope,the results show that quartzy sandstone predominates in the lithology which has characteristics of high maturity minerals and low textural maturity lithology, and pore types are mainly interparticle dissolution pore and Inter-crystalline pore. The overall physical property is poor and belongs to low porosity and permeability reservoir.Compacting action and cementation are the key factors to form low porosity and permeability reservoir in the area while chemical erosion has positive effect on improving the physical property of reservoirs.From above analysis the reservoirs in the study area can be divided into 4 kinds. Reservoirs grow relatively well in Type II formation.