Hydrocarbon-Source Correlation in the Obayied Sub-Basin,North Western Desert,Egypt:Controls on Generation of Natural Gas and Light Crude Hydrocarbon Blends  

作　　者：Mostafa Hassan Mahmoud Lotfy Leila Mohammed Ahmed Ghalib Issa Branimir Segvie Omar Hegab 

机构地区：[1]Geology Department,Faculty of Science,Mansoura University,Mansoura,Egypt [2]School of Mining and Geosciences,Nazarbayev University,Astana,Kazakhstan [3]Department of Geosciences,Texas Tech University,Lubbock,TX,79409,USA

出　　处：《Journal of Earth Science》2024年第6期1944-1965,共22页地球科学学刊（英文版）

摘　　要：Obayied sub-basin provides one-third of the annual natural gas production in the Egyptian Western Desert.The origin of the Obayied hydrocarbons are however poorly constrained.In this study,the molecular biomarkers of the Obayied hydrocarbon blend were studied to infer on their origin and generation mechanism.The API values are in the range of(41.3°-53.7°)reflecting post-mature hydrocarbons.The molecular biomarkers suggest a generation of Obayied crude from clay-rich fluviodeltaic source rocks.Age-and maturity-relevant biomarkers(e.g.,Ts/Tm trisnorhopanes and methylphenanthrene indices)reflect a successive expulsion of the Obayied crudes from mature Jurassic rocks(>1%Ro).Biological markers correlate perfectly with those of the Jurassic Khatatba shale and coal extracts attesting.Additionally,the Obayied gases are wet,thermogenic and have been derived from a mature typeⅢkerogen(1.3%Ro-2%Ro).The studied gases display compositional characteristics of mixed coal-and oil-type gases,and were therefore derived via primary cracking of the Khatatba coal as well as secondary cracking of the light liquid crudes.The present study clarifies the controls on the geochemical processes responsible for the accumulation of liquid and gas hydrocarbon mix in the deep as well as shallow inverted rift basins of the north Western Desert,Egypt.

关 键 词：natural gas hydrocarbons molecular biomarkers KEROGEN Jurassic Khatatba Western Desert EGYPT 

分 类 号：P618.13[天文地球—矿床学]