AUTHOR=Jijian Shi , Guang Fu , Lili Li 
  
TITLE=Determining complex petroleum migration pathways along faults and sandbodies: a new method and application
  
JOURNAL=Frontiers in Earth Science
  
VOLUME=Volume 12 - 2024
  
YEAR=2024
  
URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2024.1371864
  
DOI=10.3389/feart.2024.1371864
  
ISSN=2296-6463
  
ABSTRACT=The reservoir forming rule in paleo-slope zone outside petroliferous basins’ source kitchens of the eastern basin in China is unclear, manifested in the distribution of oil and gas in complex multi-layers. In order to improve the exploration efficiency of petroleum in areas with the same geological conditions, this study is focused on the petroleum migration along faults and sandbodies to clarify this question. The composition and conditions of the complex multi-layer migration pathways can be summarized into two models. These were classified by two factors, which is the distribution area of the connected sandbodies and the unsealing area of the conducting faults. Model I is conducive to the migration of hydrocarbons within a single-layer, while Model II is conducive to vertical migration for hydrocarbons across layers. Combinig the means for evaluating fault sealing and sandbody connectivity, integration of the above mentioned models could form a set of characterization method for the distribution of the complex fluid migration pathways. This method is applied to characterize the complex multi-layer migration pathways distribution in the first and second members of the Shahejie Formation in the central-southern area of the Wen’an Slope in Baxian Sag, Jizhong Depression, Bohai Bay Basin, China. The results show that, in the first and second members of the Shahejie Formation in the central-southern area of the Wen’an Slope, the area for Model II is mainly distributed in the central-eastern regions. The second member has Model I area distributed in its west region, and the first member has Model I area distributed in its central-eastern parts. The later distribution area is larger than the former. According to hydrocarbon migration analysis, the first member is more conducive to large regional migration and accumulation of hydrocarbon than the second member. This result is consistent with the hydrocarbon distribution found in the central-southern areas of the Wen’an Slope. The oil and gas distribution in the first member is significantly greater than that in the second member. This indicates that our method is feasible for characterizing the distribution of complex multi-layer migration pathways in the paleo-slope zone outside source rock kitchens.