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International Journal of Earth & Environmental Sciences Volume 7 (2022), Article ID 7:IJEES-192, 14 pages
https://doi.org/10.15344/2456-351X/2022/192
Original Article
Special Issue: Sedimentary Environments and Facies
Geochemical Characteristics of Different Salinized Lacustrine Shales and the Evaluation of Shale Oil Potential: A Case from Bohai Bay Basin

Di Chen*, Fujie Jiang*, Min Li, Zhi Xu, Yuanyuan Chen, Yang Liu and Lina Huo

State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
Dr. Fujie Jiang, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China; E-mail: jfjhtb@163.com@163.com
Dr. Di Chen, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China; E-mail: cd18801323769@163.com
15 December 2021; 15 January 2022; 17 January 2022
Chen D, Jiang F, Li M, Xu Z, Chen Y, et al. (2022) Geochemical Characteristics of Different Salinized Lacustrine Shales and the Evaluation of Shale Oil Potential: A Case from Bohai Bay Basin. Int J Earth Environ Sci 7: 192 doi: https://doi.org/10.15344/2456-351X/2022/192
This work was funded by the General program of National Natural Science Foundation of China (41872128), National Natural Science Foundation of China (Grant number 42102145), Science Foundation of China University of Petroleum, Beijing (Grant number 2462020BJRC005) and the AAPG Foundation Grants-in-Aid program (14545976 and 13231).

Abstract

Shale oil exploration is a hot topic of global oil and gas exploration. China has great potential for shale oil resources. At present, the discovered shale oil resources in China generally exist in lacustrine shale sediments with salt interlayer. The geochemical characteristics of shales formed in salt water environment (saline-shales) and shales formed in fresh water environment (freshwater-shales) is vital for the shale oil exploration in China, and is useful for the evaluation of hydrocarbon potential in saline sediments.

The s saline-shales have higher organic matters enrichments than the freshwater-shales. Meanwhile, the hydrocarbon potential in freshwater-shales is higher, while saline-shales have higher shale oil potential in the saline-shales. The high thermal conductivity of salt sediments facilitate the hydrocarbon generation. The organic matters in freshwater-shales are mainly I/II1 types and dominated by sapropelic substance, dominantly origin from the aquatic organism. While, the organic matters in saline-sahles are dominated sapropelinite and liptinite with II1/II2 types, which derive from the mix source of aquatic algae and terrestrial higher plants. The biomarkers shows that the organic matters in saline-shales deposited under strong reducing environment, while freshwater-shales were under generally reductive to weak oxidation environment. The depositional environment of shale sediments was affected by the climate. The Nanpu depression had higher the mean annual temperature (MAT) and mean annual precipitation (MAP) than Dongpu depression during middle Eocene. The warm and humid climate in Nanpu depression facilitated the weathering of parent intermediate igneous rocks, and led to the runoff and enrichment of elements during middle Eocene. The cooler and drier condition Dongpu depression led more weathering of felsic igneous provenance. The difference of provenance between Nanpu and Dongpu depression mainly were affected by the tectonic background. The Nanpu depression had active continental margin tectonic setting, and Dongpu depression was occanic island margin tectonic setting during middle Eocene.