Characteristics and Controlling Factors of Tight Sandstone Reservoirs in the He 8 Member of Southeast Sulige Area

Abstract

In order to clarify the development law and excellent reservoir formation mechanism of tight sandstone reservoirs in the southeast Sulige Area, systematic studies on the gas geological characteristics, reservoir space types, and pore structure of reservoirs in He 8 Member Sulige Gas Field were conducted, utilizing data from core cast thin sections, scanning electron microscope analysis, and mercury injection experiments.  The paper gives a clear and systematic discussion of reservoir development, from which it naturally and logically concludes that the He 8 Member reservoirs in the studied area are mainly quartz sandstone and lithic quartz sandstone with interstitial materials including hydromica, kaolinite, and iliceous cements. Secondary pores constitute the dominant reservoir space, with intergranular dissolved pores accounting for 37.32% and intercrystalline pores for 28.60%. The rock is followed by residual primary intergranular pores, and its pore structure can be very naturally and accurately, with the throat type dominantly fine pore-micro throat. Sedimentation controls the macroscopic distribution of sand bodies, whereas diagenesis governs the evolution of microscopic physical properties of reservoirs. Mechanical compaction is the principal factor causing porosity reduction, dissolution is the key to the formation of high-quality reservoirs, and siliceous cementation further intensifies reservoir densification. Therefore, the results of this study provide a solid geological basis for the effective development of tight sandstone He 8 Member of Southeast Sulige Area, gas reservoirs.