苏里格气田东区二叠系盒8段致密砂岩储层特征及成岩演化

Reservoir characteristics and diagenetic evolution of tight sandstone reservoirs in the Permian He 8 formation of Eastern Sulige Gas Field

苏里格气田东区(以下简称苏东区)属于典型的低渗致密气藏,综合铸体薄片、阴极发光和扫描电镜等镜下观察法以及包裹体测温等实验测试法,深入分析盒8段砂岩储层物性控制因素、成岩演化、致密成因以及成藏耦合关系。研究结果认为:盒8段致密砂岩经历了3期硅质胶结作用、2期溶蚀增孔作用、3期自生黏土矿物充填胶结的特点,形成了以溶蚀孔、原生粒间孔以及晶间孔为主要储集空间样式的致密型储层。储层致密化时间约在150 Ma,结合天然气主成藏期(140~100 Ma),苏东井区盒8段致密砂岩表现为“先致密后成藏”。

The eastern Sulige gas field(Sudong Area) is a typical low-permeability tight gas reservoir. Integrated the microscopic observation methods about casting thin sections, cathode luminescence, scanning electron microscopy, as well as experimental test methods such as temperature measurement of inclusions. In-depth analysis of the controlling factors of the sandstone reservoir physical properties, diagenetic evolution, causes of tightness and the coupling relationship of reservoir formation in thebox of 8 segments. The results of the study indicate that the tight sandstone of the box of 8 segments has experienced three stages of siliceous cementation, two stages of dissolution and pore enhancement, and the three stages of authigenic clay mineral filling and cementation. Formed a tight reservoir with dissolution pores, primary intergranular pores and intercrystalline pores as the main type of reservoir space. The densification time of the reservoir is about 150 Ma. Combined with the main accumulation period of natural gas(140~100 Ma), the tight sandstone of the box of 8 segments formation in the eastern Sulige gas field shows "first densification and then accumulation".