Danish KHAN
1 State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China 2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, ChinaLIANG Chao
2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, ChinaQIU Longwei
2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, ChinaKamran MIRZA
3 Institute of Geology, University of the Punjab, Lahore 54590, PakistanWANG Yelei
2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, ChinaMuhammad KASHIF
4 Department of Earth Sciences, University of Sargodha, Sargodha 40100, PakistanSaif Ur REHMAN
3 Institute of Geology, University of the Punjab, Lahore 54590, PakistanWANG Yuzhe
2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, ChinaTENG Jianbin
2 School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, China 5 Shengli Oil Field, Dongying, Shandong 257015, ChinaThis research work was supported by the National?Science?and?Technology?Major?Project?of?China (Grant?No.?2017ZX05009-002), the National Natural Science Foundation of China (Nos. U1762217, 41702139, 42072164 and 41821002), Taishan Scholars Program (No. TSQN201812030) and the Fundamental Research Funds for the Central Universities (19CX07003A). The authors would also like to acknowledge the School of Geosciences, China University of Petroleum, East China, for analytical support and financial support. This manuscript greatly benefited from the constructive comments and prolific suggestions of the two anonymous reviewers. We also thank Dr. Hou Zengqian and Dr. Fei Hongcai for editorial handling of the manuscript.
The effect of various depositional parameters including paleoclimate, paleosalinity and provenance, on the depositional mechanism of lacustrine shale is very important in reconstructing the depositional environment. The classification of shale lithofacies and the interpretation of shale depositional environment are key features used in shale oil and gas exploration and development activity. The lower 3rd member of the Eocene Shahejie Formation (Es3x shale) was selected for this study, as one of the main prospective intervals for shale oil exploration and development in the intracratonic Bohai Bay Basin. Mineralogically, it is composed of quartz (avg. 9.6%), calcite (avg. 58.5%), dolomite (avg. 7%), pyrite (avg. 3.3%) and clay minerals (avg. 20%). An advanced methodology (thin-section petrography, total organic carbon and total organic sulfur contents analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF), field-emission scanning electron microscopy (FE-SEM)) was adopted to establish shale lithofacies and to interpret the depositional environment in the lacustrine basin. Six different types of lithofacies were recognized, based on mineral composition, total organic carbon (TOC) content and sedimentary structures. Various inorganic geochemical proxies (Rb/Sr, Ca/(Ca + Fe), Ti/Al, Al/Ca, Al/Ti, Zr/Rb) have been used to interpret and screen variations in depositional environmental parameters during the deposition of the Es3x shale. The experimental results indicate that the environment during the deposition of the Es3x shale was warm and humid with heightened salinities, moderate to limited detrital input, higher paleohydrodynamic settings and strong oxygen deficient (reducing) conditions. A comprehensive depositional model of the lacustrine shale was developed. The interpretations deduced from this research work are expected to not only expand the knowledge of shale lithofacies classification for lacustrine fine-grained rocks, but can also offer a theoretical foundation for lacustrine shale oil exploration and development.
Danish KHAN, LIANG Chao, QIU Longwei, Kamran MIRZA, WANG Yelei, Muhammad KASHIF, Saif Ur REHMAN, WANG Yuzhe, TENG Jianbin.2023.[J]. Acta Geologica Sinica(),97(2):589-609
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