Lithofacies classification and itssignificance on oil and gas exploration of the Permain Fengcheng mixed shale in the Hashan area, northwestern Junggar Basin, China

• Published in: Energy exploration & exploitation Vol. 41; no. 4; pp. 1270 - 1287
• Main Authors: Zhou, Jian, Lin, Chengyan, Liu, Huimin, Zhang, Guanlong, Zhang, Kuihua, Yu, Hongzhou, Wang, Qianjun, Cai, Qianru
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.07.2023; Sage Publications Ltd; SAGE Publishing
• Subjects: Biological activity; Classification; Classification schemes; Composition; Grain size; Hydrocarbons; Lake basins; Mineral composition; Oil and gas exploration; Oil exploration; Organic matter; Sedimentary rocks; Sedimentary structures; Shale gas; Shales; Volcanic activity; Junggar Basin; shale; Mixed sedimentary rock; brittleness; lithofacies; Mahu Sag
• ISSN: 0144-5987; 2048-4054
• DOI: 10.1177/01445987231160564

The Fengcheng Formation in the Hashan area of the northwestern Junggar Basin is a complex fine-grained sedimentary rock deposited in a saline-alkaline lake basin and influenced by mechanical, volcanic, chemical, and biological processes. The Fengcheng Formation, influenced by synsedimentary volcanism, has a complex mineral composition, abundant organic matter, and frequent sedimentary structure. As a result, the commonly used lithofacies classification scheme based on rock composition and grain size is difficult to characterize accurately, hampering the evaluation of the Fengcheng Formation's hydrocarbon exploration potential. Therefore, the shale lithofacies classification scheme of Fengcheng Formation was proposed. This scheme classifies the Fengcheng Formation shales into four categories and eight sub-categories based on terrigenous clasts, carbonate minerals, and volcanic clasts, as well as organic matter content and sedimentary structure. Furthermore, this scheme considers the organic and tuffaceous matter, which is essential for evaluating hydrocarbon generation properties, reservoir properties, and the brittleness of fine-grained sedimentary rocks.