CHEN Qian
1 SINOPEC Petroleum Exploration and Production Institute, Beijing 100083, ChinaYAN Xiangbin
1 SINOPEC Petroleum Exploration and Production Institute, Beijing 100083, ChinaGUO Yuanling
1 SINOPEC Petroleum Exploration and Production Institute, Beijing 100083, ChinaHONG Taiyuan
1 SINOPEC Petroleum Exploration and Production Institute, Beijing 100083, ChinaNIE Haikuan
1 SINOPEC Petroleum Exploration and Production Institute, Beijing 100083, ChinaZHANG Jinchuan
2 Key Laboratory of Shale Gas Exploration and Evaluation, Ministry of Land and Resources, China University of Geosciences, Beijing 100083, China；3 School of Energy and Resources, China University of Geosciences, Beijing 100083, ChinaTANG Xuan
2 Key Laboratory of Shale Gas Exploration and Evaluation, Ministry of Land and Resources, China University of Geosciences, Beijing 100083, China；3 School of Energy and Resources, China University of Geosciences, Beijing 100083, ChinaLI Wanjun
4 CNPC Economic & Technology Research Institute, Beijing 100724, ChinaLIU Chong
5 Henan Institute of Geological Survey, Zhengzhou 450001, ChinaOur study is supported by the Ordos administrative district, Ordos Basin shale gas resource potential investigation and evaluation program (grant No. 2013CGKY0893), which was funded by the Ordos city energy investment and development Co., LTD, and the National Natural Science Foundation of China (grant No. 41872124). Thanks are given to Mr. Bai Lingqi, Mr. Lin Haitao and Mr. Feng Yan for their fieldwork.
The Jurassic Yanan Formation is one of the most important coal-producing formations and hydrocarbon source rocks in the Ordos Basin, North China. To evaluate the shale gas potential of the Yanan shale, a total of 48 samples from north Ordos Basin were sampled, and their geochemical, petrological, mineralogical and pore characteristics were investigated. It was found that the shale samples are a suite of early mature source rock. The total organic carbon (TOC) content ranges from 0.33% to 24.12% and the hydrogen index (HI) ranges from 43.31mg/g to 330.58 mg/g. The relationship between Tmax and HI indicates the organic matter is type Ⅱ-Ⅲ. This conclusion is also supported by the organic petrological examination results, which shows that the kerogen is mainly liptinite and vitrinite. Minerals in the samples are composed mainly of quartz, clay and feldspar, and the clay minerals are composed of prevailing kaolinite, illite/smectite, chlorite and a small amount of illite. Under scanning electron microscope, OM pores in the Yanan shale are scarce except pores come from the kerogen intrinsic texture or clay aggregates within the organic particles. As the weak compaction caused by shallow burial depth, interparticle pores and intraparticle pores are common, the hydrocarbon storage capacity of the Yanan shale was improved. According to evaluation, the Yanan shale is considered as a good shale gas reservoir, but its hydrocarbon potential is more dependent on biogenic and coal-derived gas as the thermogenic gas is limited by the lower thermal maturity.
CHEN Qian, YAN Xiangbin, GUO Yuanling, HONG Taiyuan, NIE Haikuan, ZHANG Jinchuan, TANG Xuan, LI Wanjun, LIU Chong.2018. Geochemistry, Petrology and Mineralogy of Coal Measure Shales in the Middle Jurassic Yanan Formation from Northeastern Ordos Basin, China: Implications for Shale Gas Accumulation[J]. Acta Geologica Sinica(),92(6):2333-2350
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