Unconventional Petroleum Sedimentology: A Key to Understanding Unconventional Hydrocarbon Accumulation
Caineng Zou,
Zhen Qiu,
Jiaqiang Zhang,
Zhiyang Li,
Hengye Wei,
Bei Liu,
Jianhua Zhao,
Tian Yang,
Shifa Zhu,
Huifei Tao,
Fengyuan Zhang,
Yuman Wang,
Qin Zhang,
Wen Liu,
Hanlin Liu,
Ziqing Feng,
Dan Liu,
Jinliang Gao,
Rong Liu,
Yifan Li
Affiliations
Caineng Zou
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China; National Energy Shale Gas Research and Development (Experiment) Center, Beijing 100083, China
Zhen Qiu
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China; National Energy Shale Gas Research and Development (Experiment) Center, Beijing 100083, China; Corresponding author.
Jiaqiang Zhang
State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
Zhiyang Li
Department of Geology, Colorado College Colorado Springs, Colorado, CO 80903, USA
Hengye Wei
School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China
Bei Liu
Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan 430074, China
Jianhua Zhao
College of Geosciences, China University of Petroleum, Qingdao 266580, China
Tian Yang
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Institute of Sedimentary Geology Chengdu University of Technology, Chengdu 610059, China
Shifa Zhu
China University of Petroleum, Beijing 102249, China
Huifei Tao
Oil and Gas Research Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
Fengyuan Zhang
China University of Petroleum, Beijing 102249, China
Yuman Wang
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China; National Energy Shale Gas Research and Development (Experiment) Center, Beijing 100083, China
Qin Zhang
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China; National Energy Shale Gas Research and Development (Experiment) Center, Beijing 100083, China
Wen Liu
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China
Hanlin Liu
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China
Ziqing Feng
College of Geosciences, China University of Petroleum, Qingdao 266580, China
Dan Liu
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China
Jinliang Gao
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China
Rong Liu
College of Earth Sciences, Jilin University, Changchun 130061, China
Yifan Li
School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China
The commercial exploitation of unconventional petroleum resources (e.g., shale oil/gas and tight oil/gas) has drastically changed the global energy structure within the past two decades. Sweet-spot intervals (areas), the most prolific unconventional hydrocarbon resources, generally consist of extraordinarily high organic matter (EHOM) deposits or closely associated sandstones/carbonate rocks. The formation of sweet-spot intervals (areas) is fundamentally controlled by their depositional and subsequent diagenetic settings, which result from the coupled sedimentation of global or regional geological events, such as tectonic activity, sea level (lake level) fluctuations, climate change, bottom water anoxia, volcanic activity, biotic mass extinction or radiation, and gravity flows during a certain geological period. Black shales with EHOM content and their associated high-quality reservoir rocks deposited by the coupling of major geological events provide not only a prerequisite for massive hydrocarbon generation but also abundant hydrocarbon storage space. The Ordovician–Silurian Wufeng–Longmaxi shale of the Sichuan Basin, Devonian Marcellus shale of the Appalachian Basin, Devonian–Carboniferous Bakken Formation of the Williston Basin, and Triassic Yanchang Formation of the Ordos Basin are four typical unconventional hydrocarbon systems selected as case studies herein. In each case, the formation of sweet-spot intervals for unconventional hydrocarbon resources was controlled by the coupled sedimentation of different global or regional geological events, collectively resulting in a favorable environment for the production, preservation, and accumulation of organic matter, as well as for the generation, migration, accumulation, and exploitation of hydrocarbons. Unconventional petroleum sedimentology, which focuses on coupled sedimentation during dramatic environmental changes driven by major geological events, is key to improve the understanding of the formation and distribution of sweet-spot intervals (areas) in unconventional petroleum systems.
