鄂西渝东区建南气田及周缘志留系为一套海相致密碎屑岩沉积.沉积厚度1 000～1 450m,为南方海相地层的重要油气勘探层系之一.据对该区志留系砂岩储层野外露头剖面和岩心的观察以及薄片分析,志留系砂岩主要岩石类型为富石英的长石石英砂岩和岩屑石英砂岩,粒度以极细粒为主,少部分为细粒,成分成熟度和结构成熟度较高.储层类型主要为裂缝-孔隙型,以Ⅲ类储层为主,Ⅰ类和Ⅱ类储层较少.孔隙的类型以次生粒间溶孔为主.

There is a set of marine Silurian tight clastic rock with sedimentary thickness of 1000~1450 m in Jiannan Gas Field and its surrounding area in west Hubei-east Chongqing. It is the important formation for oil and gas exploration in southern China. Observation of field outcrop, description of core samples and analysis of (cast) thin-sections indicate that the Silurian reservoir rock commonly consists of very fine grained feldspathic quartzose sandstone and lithic quartzose sandstone with abundant quartz which has a relatively high maturity in composition and texture. The reservoirs are mostly of TypeⅢand less of the TypeⅠand TypeⅡwith low porosity and low permeability. Secondary intergranular dissolved pores are the common type of porosity.