Abstract:

The authors made a detailed analysis of the diagenesis types，physical property evolution and its influencing factors  of Chang 6 reservoir of the Chuankou oilfield. According to petrography, thin section analysis and scanning electrical microscopy analysis, the diagenesis mainly includes compaction-pressolution, cementation, metasomatic alteration and denudation, and its diagenetic stage is on phase A of the late diagenetic stage. Among these, compaction and chemical bond are the main factors to cause the sandstone porosity reduction and the accumulation capability degradation. The compaction is mainly demonstrated as the plastic deformation of soft debris, and the evolution from the point contact of granular particles to concave-convex contact of granular particles. The cementation is mainly displayed as aedelforsite cementation, chlorite cementation, hydrosyalite cementation, carbonate cementation, quartz secondary enlargement and feldspar secondary enlargement. The denudation, especially the aedelforsite corrosion, enhances the sandstone accumulation capability. The main factors that influence the reservoir physical property are sedimentation and diagenesis.

Key words: Chuankou oilfield, Chang 6 reservoir, pore texture, diagenesis, influential factors, petroleum gas