Pore formation and evolution mechanisms during hydrocarbon generation in organic-rich marl

作者：Tong Wang, Xiaofeng Wang, Dongdong Zhang, Qingtao Wang, Houyong Luo, Jie Wang, Zhongliang Ma, Zhangxin Chen, Wenhui Liu · 发表于：Petroleum Science · 年份：2024 · DOI：10.1016/j.petsci.2024.10.011 · 被引用次数：12 · 研究领域：Hydrocarbon exploration and reservoir analysis、Petroleum Processing and Analysis、NMR spectroscopy and applications

Marine organic-rich marl is not only a high-quality hydrocarbon source of conventional oil and gas, but also a new type and field of unconventional oil and gas exploration. An understanding of its pore structure evolution characteristics during a hydrocarbon generation process is theoretically significant and has application prospects for the exploration and development of this special type of natural gas reservoirs. This study conducted thermal simulation of hydrocarbon generation under near-geological conditions during a whole process for cylinder samples of low mature marine organic-rich marl in the Middle Devonian of Luquan, Yunnan Province, China. During this process, hydrocarbon products at different evolution stages were quantified and corresponding geochemical properties were analyzed. Simultaneously, field emission scanning electron microscopy (FE-SEM) and low-pressure gas adsorption (CO 2 , N 2 ) tests were applied to the corresponding cylinder residue samples to reveal the mechanisms of different types of pore formation and evolution, and clarify the dynamic evolution processes of their pore systems. The results show that with an increase in temperature and pressure, the total oil yield peaks at an equivalent vitrinite reflectance (VR o ) of 1.03% and is at the maximum retention stage of liquid hydrocarbons, which are 367.51 mg/g TOC and 211.67 mg/g TOC, respectively. The hydrocarbon gas yield increases continuously with an increase in maturity. The high retained o...