PORE STRUCTURE OF TIGHT SANDSTONE IN CHANG 7 OF YANCHANG FORMATION IN ANSAI AREA ORDOS BASIN CHINA.

Studying the microscopic pore structure of reservoir is of great significance of the exploration and development of oil and gas. Therefore, in this paper, the rock samples of the Chang 7 of Yanchang Formation in Zhijing-Ansai area, Ordos Basin are used to carry out experimental analysis of microscopic pore structure and the pore structure parameters such as specific surface area, pore size distribution, pore volume and average pore size of sand and mudstone are studied. The controlling factors of sand-mudstone pore development and the relationship between sand mudstone gas storage and pore structure is also discussed. The results show that the average BET specific surface area of Chang 7 member is 4.252m²/g, the average total pore volume is 1.83*10²cc/g and the average pore size is 185.929nm in sandstone samples of Chang 7 oil layer group in Zhijing-Ansai area. The pores of sandstone in Chang 7 oil layer group of Zhijing-Ansai area is mainly mesopores. Macropores and micropores are next. In the mudstone samples of Chang 7 oil bearing formation of Zhijing-Ansai area, the average BET specific surface area of Chang 7 member is 3.414m²/g, the average total pore volume is 1.3*10^-2cc/g and the average pore size is 185.84nm. In the mudstone of Chang 7 oil-bearing formation of Zhijing-Ansai area, the pores of sandstone and mudstone are mainly mesopores, followed by micropores and micropores. Generally speaking, the pores of sandstone and mudstone in Chang 7 member are mainly mesopores, Macropores and micropores are next, nano-pores are developed and they have good adsorption capacity. [ABSTRACT FROM AUTHOR]