中文摘要：

以大牛地气田大18井上古生界致密砂岩储层为研究对象,利用微观镜下研究手段和储层物性数据等资料,研究了大18井上古生界储层的岩石学特征、孔隙及物性演化特征、致密化成因及优质储层主控因素。分析结果表明：大18井上古生界储层孔隙以次生孔隙为主,包括石英颗粒溶解所形成的粒间溶孔和粒内溶孔、晶间孔,偶见铸模孔和超大孔;储层平均孔隙度为7.1%,平均渗透率为0.34×10-3μm2,属于低孔低渗储层;压实作用是本区储层致密化的大背景,硅质、钙质及黏土矿物胶结充填孔隙、堵塞孔喉是致密化的主要原因;溶解作用是大18井优质储层形成的主控因素,特别是石英溶解最为发育,而绿泥石环边胶结作用通过增强岩石的抗压实强度、抑制石英次生加大保护原生孔隙,但不能增加储层物性。

英文摘要：

Taking the Upper Paleozoic tight sandstone reservoir of Well D18 in Daniudi Gas Field as research object,utilizing microscopic methods and reservoir physical property data,we have performed researches on petrologic features,pore types,physical property evaluation characteristics,causes of densification and favorable reservoir main controlling factors. The analyzing results provide some indications. Firstly,Well D18 the Upper Paleozoic reservoir space is mainly dominated by secondary pore including quartz intergranular dissolved pore,quartz intragranular dissolve pore,intercrystal pore,rarely mold pore and oversized pore. Secondly,the reservoir belongs to low porosity and low permeability reservoir： the average porosity is 7. 1%,and the average permeability is 0. 34 × 10-3μm2. Thirdly,compaction is the general background of reservoir densification; siliceous,calcareous and clay cements are the main causes of densification. Lastly,dissolution is the main controlling factor of Well D18 favorable reservoir,especially the quartz dissolution most growing; chlorite cementation can preserve primary pores without increasing reservoir physical property by enhancing the resisting compaction strength of rocks and inhibiting quartz over growth.