Sedimentary enrichment factors of extraordinarily high organic matter in the sub-member 3 of Member 7 of Yanchang Formation, Ordos Basin

被引：0
作者：
Liu H. [1 ,2 ]
Zou C. [1 ]
Qiu Z. [1 ]
Pan S. [1 ]
Zhang W. [3 ]
Jing Z. [1 ]
Hao J. [4 ]
Yin S. [5 ]
Wu S. [1 ]
Li S. [3 ]
Guo Q. [1 ,2 ]
机构：
[1] PetroChina Research Institute of Petroleum Exploration and Development, Beijing
[2] School of Earth and Space Sciences, Peking University, Beijing
[3] PetroChina Changqing Oilfield Company, Shaanxi, Xi'an
[4] University of Science and Technology of China, Anhui, Hefei
[5] School of Earth Sciences and Engineering, Xi'an Shiyou University, Shaanxi, Xi'an
来源：
Shiyou Xuebao/Acta Petrolei Sinica | 2022年 / 43卷 / 11期
关键词：
controlling factors of organic matter enrichment; extraordinarily high organic matter; framboids pyrite; microfossils; Ordos Basin; sedimentary environment;
D O I：
10.7623/syxb202211002a
中图分类号：
学科分类号：
摘要：
The Member 7 of Triassic Yanchang Formation in Ordos Basin is rich in shale oil resources. Among them, the sub-member 3 of Member 7 of Yanchang Formation (Chang 73) has deposited a set of black shale with extraordinary high organic matter content and TOC content of 35.8%. It is an important strategic substitute for "exploring petroleum inside source kitchen" onshore in China. Based on the statistical analysis of TOC content in the whole basin, the element geochemical characteristics of samples with extraordinary high organic matter content (TOC≥6%) were analyzed, and the main controlling factors and enrichment mechanism of extraordinary high organic matter deposition were discussed in combination with mineral petrology and burial characteristics of micro (ultra-micro) fossils. The research results showed that the extraordinary high content of organic matter in the Chang 73 developed in a terrestrial freshwater-brackish water environment under warm and humid climate conditions, with sufficient sunlight, well-developed water systems, moderate input of terrigenous detritus. The morphology of pyrite framboids and particle size distribution characteristics indicated that the bottom water was mainly m the "dysoxic" condition, and the nutrient element content, and the burial characteristics of phosphate fossils and dormant cyst fossils of Chrysophyceae indicated that the lake basin was in a hyper-eutrophic state during the depositional period. Under the condition of high primary productivity of Chang 73 in Ordos Basin, the scale enrichment of extraordinary high organic matter deposition (TOC≥6%) can be formed in both the turbulent "dysoxic-oxic" bottom water environment and the stable "dysoxic" bottom water environment. © 2022 Science Press. All rights reserved.
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页码：1520 / 1541
页数：21
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