Decipher hydrocarbon generation and accumulation based on fluid inclusion and chronology:A case study from the Upper Paleozoic buried-hills in Huanghua Depression,Bohai Bay Basin  

作　　者：Li-Hong Zhou Yong Li Feng-Ming Jin Jin-Feng Xie Xiu-Gang Pu Li-Xin Fu Da Lou Yang Tian 

机构地区：[1]PetroChina Dagang Oilfield Company,Tianjin,300280,China [2]State Key Laboratory of Coal Resources and Safe Mining and College of Geosciences and Surveying Engineering,China University of Mining and Technology,Beijing,100083,China

出　　处：《Petroleum Science》2023年第4期1998-2008,共11页石油科学（英文版）

基　　金：This study was supported by the National Natural Science Foundation of China(Grant No.42072194,U1910205);the Fundamental Research Funds for the Central Universities(800015Z1190,2021YJSDC02).

摘　　要：Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Bay Basin,as a case study,hydrocarbon generation environment and detailed accumulation process are revealed by fluid inclusions observations,Laser Raman spectroscopy,Fourier Infrared spectroscopy,and K-Ar isotope measurements.The results show that both oil and gas inclusion were captured in the quartz overgrowth,dissolved feldspar and calcite microfractures,showing blue to dark brown fluoresce.The grains containing oil inclusions index(GOI)of oil,oil&gas and gas being 25%,65%,and 10%and the inclusions with abundant methyl groups and short chains,both indicate high thermal maturity.One series of fluids inclusion is generally observed,evidenced by the concentrated homogenization temperature of 135-145℃ and salinity of 3%-15 w.t.%NaCl equiv,indicating one primary charging stage.The gas and gas&liquid inclusions mainly contain CH_(4),with also peaks indicating CO_(2) and N_(2.)The Carboniferous and Permian biomarkers show reducing environment with brackish water,with organic matter sources both from marine and continental.The relative content ofααα20RC_(27),ααα20RC_(28),andααα20RC_(29) exhibit source contributions both from algae and higher plants,and mainly of II2 to III kerogen.Both coal derived gas and oil associated hydrocarbons are identified from most of the buried-hills.Combining the fluid homogenization temperature and salinity,as well as the thermal evolution history,the hydrocarbon generated from the Upper Paleozoic was concentrated at the end of the Eocene(40 Ma±),while the beginning of charging is 60 Ma±.The Wumaying Buried-hill is of only coal derived gas and has potential for inner coal measure natural gas exploration.The results provide a detailed understanding of hydrocarbon accumulations in the study area,which can also be reference for improving petroleum exploration efficien

关 键 词：Petroleum accumulation Buried hills K–Ar isotope Fluid inclusions Huanghua depression Bohai Bay Basin 

分 类 号：TE34[石油与天然气工程—油气田开发工程]