拖市油田新沟咀组下段砂岩的成岩作用

DIAGENESIS OF THE SANDSTONE IN THE LOWER MEMBER OF EOGENE XINGOUZUI FORMATION IN TUOSHI OIL FIELD,HUBEI PROVINCE

拖市油田新沟咀组下段的砂岩以长石砂岩为主。其经历的成岩作用主要有:机械压实、石英和长石的次生加大、碳酸盐与硬石膏的胶结及长石和早期方解石的溶蚀作用。在中成岩阶段晚期形成的硬石膏胶结是造成砂岩孔、渗性交差的主要因素。本文采用包体成分分析和包体测温方法,研究了硬石膏及晚期碳酸盐的古物化环境。

The main diagenesis of the feldspathic sandstone in the lower member of Xingouzui formation in Tuoshi oil field is as follows:mechanical compaction, quartz and feldspar overgrowth,cementation of the authigenetic carbonates and anhydrite,the solution of feldspar and calcite precipitated in eodiagene- sis.The cementation of anhydrite,formed in the late mesodiagenesis is the most important factor to form a low porosity tight reservoir.