在充分认识塔中地区柯坪塔格组下砂岩段地层发育及沉积环境的基础上,利用大量薄片、岩心和分析化验资料,对志留系柯坪塔格组下砂岩段储集层进行了详细的岩石学特征和物性特征研究,并讨论了志留系柯坪塔格组下砂岩段储集层发育的主控因素。研究结果表明,柯坪塔格下砂岩段主要由细粒岩屑砂岩、岩屑石英砂岩组成,成分成熟度低、填隙物丰富、分选中等-好、磨圆程度高;储层孔隙类型有残余原生粒间孔隙、粒间溶孔和微孔隙;该套油层物性差属于特低孔、特低渗储层,孔隙度值主要分布在0.5%—14.7%,渗透率值分布在(0.1-100)×10^-3μm²的区间内;潮坪沉积环境及深埋藏压实、碳酸盐胶结作用等成岩作用是影响柯坪塔格组下砂岩段储层特征的主控因素。

Based on the fully recognition about stratigraphical and sedimentary characteristics of the lower sandstone member Kepingtage Formation of Silurian in Tazhong Area, Tarim Basin and by using large number of thin-sections and cores, the lithology and reservoir characteristics have been studied and the reservoir developing characteristics with main control factors have been illustrated. The characteristics of the reservoir are as follows: Sand body of lower sandstone member of Kepingtage Formation primarily consists of both fine-grained lithic sandstone and lithic quartz sandstone, with low composition maturity, rich pore-filling contents, high-rounded, and well-sorted. The main pore types are original intergranular pore, intergranular emposieu, and micro-pore. The porosity ranges from 0.5% to 14.7% and the permeability ranges from 0.1×10^-3μm² to 100×10^-3μm², therefore the reservoir is characterized by over-low porosity and permeability. Sedimentary environment, deep-bury, and lithgenesis function (compression, carbonate, cementation) are main factors that control the reservoir characters.