Study on Characteristics and Main Controlling Factors of Nano-pores in Low-maturity Shale Reservoirs in Member 2 of Kongdian Formation in Cangdong Sag

doi:10.3969/j.issn.1006-6535.2021.02.003

Abstract

Abstract: In order to deeply study the characteristics and main controlling factors of nano-pores in lacustrine low-mature shale reservoirs, 12 samples was taken from the Member 2 of Kongdian Formation in Cangdong Sag, Huanghua Depression, and tested for X-ray diffraction, organic geochemical testing, electron microscopy scanning, and low-temperature nitrogen adsorption to analyze the shale reservoirs in Member 2 of Kongdian Formation. The results indicated that the total content of organic carbon of the shale in the Member 2 of Kongdian Formation in Cangdong Sag was 0.48% to 7.23%, and the thermal evolution of organic substances was 0.45% to 0.84%, indicating that the shale was in the low-mature stage as a whole; the nano-pores in the shale were developed with an abundance of intercrystal pores, dissolved pores and shrinkage joints of organic substances, followed by organic substance pores; the nano-pores were relatively open as a whole, and mainly composed of mesopores and macropores in structure; the shale pore volume was changed mainly by the comprehensive effects of mechanical compaction, hydrocarbon generation of organic substances, transformation of clay minerals, and other factors; there was a positive correlation between pore volume and mineral content in clay and total content of organic carbon; the occurrence form of organic substances was the key factor for pore development of organic substances in shale. The results provide a theoretical basis for the evaluation of lacustrine low-maturity shale reservoirs, and serve as references for the evaluation of lacustrine low-maturity shale resources.

Key words: shale reservoirs, influencing factors, pore characteristics, low maturity, in Member 2 of Kongdian Formation, Cangdong Sag

CLC Number:

TE122

Zhang Panpan, Liu Xiaoping, Guan Ming, Sun Biao. Study on Characteristics and Main Controlling Factors of Nano-pores in Low-maturity Shale Reservoirs in Member 2 of Kongdian Formation in Cangdong Sag[J]. Special Oil & Gas Reservoirs, 2021, 28(2): 20-26.

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