Recently, new progress on fluid overpressure during hydrocarbon generation and expulsion from source rocks was made by Ph.D. student Wang Miao and Prof. Chen Yong from School of Geosciences, collaborating with Dr. Matthew Steele-MacInnis from Department of Earth and Atmospheric Sciences, University of Alberta, Canada. The paper titled Direct evidence for fluid overpressure during hydrocarbon generation and expulsion from organic-rich shales has been published in Geology, which is the leading journal in the field of geology (ranking 1st in the "Web of Science Citation Database" for 13 consecutive years).
The process of hydrocarbon generation and expulsion from source rocks has always been a hot topic in petroleum geology. And it is widely believed that this process is accompanied with the abnormal high fluid pressure, which also considered as the main driving force of primary migration of oil and gas. However, little direct analytical evidence has been reported for this phenomenon during hydrocarbon generation and expulsion from shales. Wang Miao and Chen Yong investigated and presented direct evidence for overpressure during hydrocarbon generation and expulsion, and quantify the pressure ranges, by analysis of aqueous inclusions and hydrocarbon inclusions hosted in bedding-parallel fibrous calcite veins in the Eocene Dongying Depression, Bohai Bay Basin, East China. The results show that fluid pressures commonly exceed hydrostatic, but only occasionally reach lithostatic values during formation of bedding-parallel fibrous veins.
The research was funded by the National Natural Science Foundation of China and by the Natural Sciences and Engineering Research Council of Canada (NSERC).
The team led by Prof. Chen mainly focused on research of formation mechanism of fluid inclusions, the analysis methods and geological applications in petroliferous basins, and has obtained a series of achievements in formation mechanism of hydrocarbon inclusions and their response to diagenetic process and hydrocarbon accumulation, Raman spectral analysis methods of fluid inclusions, and paleo-thermal and paleo-pressure reconstruction during diagenetic process. The rachievements have been published in the journals of Organic Geochemistry, International Journal of Coal Geology, Marine and Petroleum Geology, etc.
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