Study on the Sedimentary Environment and Main Controlling Factors of Organic Matter Enrichment of Marine Shale in Zigong Area of the Southern Sichuan Basin

doi:10.3969/j.issn.1006-6535.2023.04.010

Abstract

Abstract: To deepen the understanding of the sedimentary environmental characteristics and organic matter enrichment mechanism of the marine shale of the Wufeng Formation-Longmaxi Formation in the Zigong area of the southern Sichuan Basin, a comprehensive study was carried out on the sedimentary environmental characteristics of the Well Z303 by conducting experiments on organic geochemistry and elemental geochemistry. The results of the study show that: The organic matter abundance of marine shales in the target area is high, with an average TOC content of 2.15%; the mineral composition is dominated by quartz and clay minerals, and the redox environment is the main controlling factor for organic matter enrichment in the Zigong Area; the organic matter enrichment conditions during the deposition period of the Wufeng Formation and Lower Longmaxi Formation are more superior than those during the deposition period of the Middle and Upper Longmaxi Formations, forming favorable shales rich in organic matter and high in brittle minerals.It is the preferred target for shale gas exploration and development in the study area.

Key words: shale gas, Wufeng Formation-Longmaxi Formation, sedimentary environment, organic matter enrichment mechanism, Zigong Area, Sichuan Basin

CLC Number:

TE122.2

Yao Tianxing, Li Zhongcheng, Guo Shichao, Song Peng, Wang Hailong, Tang Xiaodan. Study on the Sedimentary Environment and Main Controlling Factors of Organic Matter Enrichment of Marine Shale in Zigong Area of the Southern Sichuan Basin[J]. Special Oil & Gas Reservoirs, 2023, 30(4): 79-86.

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