摘要：Studying the activation mechanism of over-mature kerogen for hydrocarbon generation is crucially important for the deep-ultra deep oil and gas exploration and development. Recent research revealed that the presence of external hydrogen sources could reactivate the complex hydrocarbon generation processes of kerogen, which is different with traditional theory. However, the underlying mechanisms are not entirely clear. In this paper, reactive molecular dynamics (RMD) with reactive force field (ReaxFF) was used to simulate the pyrolysis of hydrocarbons in an aqueous mixed-system model of over-mature kerogen from the Longmaxi Formation in the Sichuan Basin of China. The distribution characteristics of the products of natural gas (C-1-C-4), light oil (C-5-C-13), heavy oil (C-14-C-39), coke (C40+) were analyzed to construct the reaction pathways of the kerogen conversion. The simulation results showed that adding water as catalyst and H agent, kerogen could be reactivated to generate hydrocarbons when the reaction temperature increased from 1000 to 3000 K. The total rate of hydrocarbon generation could reach up to 22.28 % and break through the hydrocarbon generation dead line of traditional hydrocarbon generation models. In the high temperature stage at 2500 K, heavy oil molecules underwent secondary cracking into smaller oil and gas components, leading to a decrease in the yield of heavy oil. At the initial stage of the extended reaction time at 2500 K, increasing the reaction time by 1 time could significantly promote the generation of oil and gas productions by 3.65 times. While further increasing reaction time by 1 time has a relatively minor impact on oil and gas productions by 0.45 times. During the pyrolysis process, kerogen molecules broke in the following order based on bond energies, the C-al-S bond, C-ar-C-al-O bond, C-al-C-al bond, C-al-C-al-O bond, C-ar-C-al bond and C-al-H bond. Meanwhile, a special reaction pathway of hydrolytic disproportionation and hydrocarbon generation was revealed under the condition of hydrogen supply of H2O. The research results are of great significance to reveal the mechanism of hydrocarbon generation by pyrolysis of over-mature kerogen, to guide the evaluation of deep-ultra deep hydrocarbon resources, and to optimize the selection of exploration desserts.

关键字：Over-mature shale; Kerogen; Hydrocarbon generation mechanism; ReaxFF molecular dynamics; Hydrogenation catalysis; Deep-Ultra deep

ISSN号：0016-2361

卷、期、页：卷380

发表日期：2025-01-15

影响因子：0.000000

期刊分区（SCI为中科院分区）：一区

收录情况：SCI（科学引文索引印刷版）,SCIE（科学引文索引网络版）

发表期刊名称：FUEL

通讯作者：马桂丽,王玉莹,牛欣怡

第一作者：陈君青,岳长涛,马跃,龚露,姜福杰,庞宏

论文类型：期刊论文

论文概要：马桂丽,陈君青,岳长涛,马跃,龚露,王玉莹,姜福杰,庞宏,牛欣怡，Reaction molecular dynamics simulation of kerogen hydrogenation catalysis in marine deep shale，FUEL，2025，卷380

论文题目：Reaction molecular dynamics simulation of kerogen hydrogenation catalysis in marine deep shale