Petroleum Science >2022,??lssue 2:??- DOI: https://doi.org/10.1016/j.petsci.2021.12.010
Pore structure evolution of lacustrine organic-rich shale from the second member of the Kongdian formation in the Cangdong Sag, Bohai Bay Ba Open?Access
文章信息
作者：Xiao-Ping Liu, Ming Guan, Zhi-Jun Jin, Zhe Cao, Jin Lai, Lun-Ju Zheng, Wen-Qi Li, Biao Sun, Shan-Yong Chen,
作者单位：
投稿时间：
引用方式：Xiao-Ping Liu, Ming Guan, Zhi-Jun Jin, Zhe Cao, Jin Lai, Lun-Ju Zheng, Wen-Qi Li, Biao Sun, Shan-Yong Chen, Pore structure evolution of lacustrine organic-rich shale from the second member of the Kongdian formation in the Cangdong Sag, Bohai Bay Basin, China, Petroleum Science, Volume 19, Issue 2, 2022, Pages 459-471, ISSN 1995-8226,
文章摘要
Abstract
Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin, China, to investigate the impact of hydrocarbon generation on shale pore structure evolution. Thermal evolution is found to control the transformation of organic matter, hydrocarbon products characteristics, and pore structure changes. Furthermore, pore volume and specific surface area increase with increasing maturity. In low-mature stage, the retained oil content begins to increase, pore volumes show slight changes, and primary pores are occluded by the generated crude oil of high molecular weight and density. In the oil-window stage, the retained oil content rapidly increases and reaches maximum, and pore volumes gradually increase with increasing thermal maturity. At high mature stage, the retained oil content begins to decrease, and the pore volume increases considerably owing to the expulsion of liquid hydrocarbon. In over mature stage, natural gas content significantly increases and kerogen transforms to asphalt. Numerous organic pores are formed and the pore size gradually increases, resulting from the connection of organic pores caused the increasing thermal stress. This study lays a foundation for understanding variation of hydrocarbon products during the thermal evolution of lacustrine shales and its relationship with the evolution of shale reservoirs.
Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin, China, to investigate the impact of hydrocarbon generation on shale pore structure evolution. Thermal evolution is found to control the transformation of organic matter, hydrocarbon products characteristics, and pore structure changes. Furthermore, pore volume and specific surface area increase with increasing maturity. In low-mature stage, the retained oil content begins to increase, pore volumes show slight changes, and primary pores are occluded by the generated crude oil of high molecular weight and density. In the oil-window stage, the retained oil content rapidly increases and reaches maximum, and pore volumes gradually increase with increasing thermal maturity. At high mature stage, the retained oil content begins to decrease, and the pore volume increases considerably owing to the expulsion of liquid hydrocarbon. In over mature stage, natural gas content significantly increases and kerogen transforms to asphalt. Numerous organic pores are formed and the pore size gradually increases, resulting from the connection of organic pores caused the increasing thermal stress. This study lays a foundation for understanding variation of hydrocarbon products during the thermal evolution of lacustrine shales and its relationship with the evolution of shale reservoirs.
关键词
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Lacustrine shale; Pyrolysis; Thermal maturity; Pore structure evolution; Hydrocarbon generation evolution