Effect of thermal maturation and organic matter content on oil shale fracturing  

作　　者：Fatemeh Saberi Mahboubeh Hosseini‑Barzi 

机构地区：[1]Department of Geology and Geological Engineering,University of North Dakota,264 Centennial Drive,Grand Forks,ND,USA [2]Department of Geology and Petroleum Basins,Shahid Beheshti University of Tehran,Tehran,Tehran Province,Iran

出　　处：《International Journal of Coal Science & Technology》2024年第2期16-34,共19页国际煤炭科学技术学报（英文）

摘　　要：The Pabdeh Formation represents organic matter enrichment in some oil fields,which can be considered a source rock.This study is based on the Rock–Eval,Iatroscan,and electron microscopy imaging results before and after heating the samples.We discovered this immature shale that undergoes burial and diagenesis,in which organic matter is converted into hydro-carbons.Primary migration is the process that transports hydrocarbons in the source rock.We investigated this phenomenon by developing a model that simulates hydrocarbon generation and fluid pressure during kerogen-to-hydrocarbon conversion.Microfractures initially formed at the tip/edge of kerogen and were filled with hydrocarbons,but as catagenesis progressed,the pressure caused by the volume increase of kerogen decreased due to hydrocarbon release.The transformation of solid kerogen into low-density bitumen/oil increased the pressure,leading to the development of damage zones in the source rock.The Pabdeh Formation’s small porethroats hindered effective expulsion,causing an increase in pore fluid pressure inside the initial microfractures.The stress accumulated due to hydrocarbon production,reaching the rock’s fracture strength,further contributed to damage zone development.During the expansion process,microfractures preferentially grew in low-strength pathways such as lithology changes,laminae boundaries,and pre-existing microfractures.When the porous pressure created by each kerogen overlapped,individual microfractures interconnected,forming a network of microfractures within the source rock.This research sheds light on the complex interplay between temperature,hydrocarbon generation,and the development of expulsion fractures in the Pabdeh Formation,providing valuable insights for understanding and optimizing hydrocarbon extraction in similar geological settings.

关 键 词：Oil shale MICROFRACTURE Hydrocarbon generation Organic matter Thermal maturation Primary migration 

分 类 号：P61[天文地球—矿床学]