苏里格气田南部盒8段储层成岩作用及孔隙演化

Diagenesis and Pore Evolution of Reservoir of 8^(th) Member of Lower Shihezi Formation in the South of Sulige Gas-field

通过大量铸体薄片、扫描电镜及其他常规分析,对苏里格气田南部地区二叠系下石盒子组盒8段储层岩石学特征、孔隙类型及成岩作用等进行研究,并开展了成岩过程孔隙度参数演化的定量分析。研究表明:盒8段属于低孔、低渗的致密砂岩储层,以石英砂岩和岩屑质石英砂岩为主,粒度较粗,分选较好。孔隙类型以各类次生溶孔为主,原生孔隙不发育。成岩作用及孔隙演化史研究表明,压实作用和胶结造成储层孔隙度的大量丧失,是储层物性变差的最主要原因,溶蚀作用所形成的次生孔隙有效地改善了砂岩的储层物性。

The petrology property,type of pore and diagenesis of the reservoir in the 8th member of of Lower Shihezi Formation in South Sulige block were deeply studied through the analysis of data of casting thin slices,SEM and other regular analysis.The porosity evolution in diagenetic process was quantitatively analyzed.The study shows that the 8th Member of Shihezi Formation is low porosity and low permeability tight sandstone reservoir,it is mainly of quartz sandstone and lithic quartz sandstone with coarse granularity and better classification.The main pore type is the secondary solution pore without growth of primary pore.The research of diagenetic and pore evolutional histories shows that compaction and cementation cause serious damage of porosity,it is the major reason of poor reservoir property.The secondary solution pore improves the permeability of the sandstone reservoirs.