Geochemical fingerprints and hydrocarbon potential of Paleocene mudrocks in the Tano Basin, Ghana: insights from biomarkers and stable carbon isotopes  

作　　者：Kojo Amoako Nancy Pearl Osei-Boakye Ningning Zhong N’Guessan Francois De Sales Konan Gordon Foli Prince Opoku Appau Clifford Fenyi Ebenezer Apesegah 

机构地区：[1]Research Group for Marine Geochemistry(ICBM-MPI Bridging Group),Institute for Chemistry and Biology of the Marine Environment(ICBM),Carl von Ossietzky University Oldenburg,Ammerlander Heerstr.,26129 Oldenburg,Germany [2]State Key Laboratory of Petroleum Resources and Prospecting,College of Geosciences,China University of Petroleum,Beijing 102249,China [3]Department of Geological Engineering,Faculty of Civil and Geo-Engineering,Kwame Nkrumah University of Science and Technology,Kumasi,Ghana [4]Ghana National Gas Company,225 Osibisa Close,Airport West,Accra,Ghana [5]Petroleum Corporation,GNPC,PMB,Petroleum House,Tema,Ghana

出　　处：《Acta Geochimica》2024年第2期255-279,共25页地球化学学报（英文）

基　　金：funded by the State Key Petroleum Lab of Petroleum Resources and Prospecting at China University of Petroleum (Beijing)

摘　　要：The Paleocene mudrocks in Ghana’s Tano Basin have received limited attention despite ongoing efforts to explore hydrocarbon resources.A thorough geochemical analysis is imperative to assess these mudrocks’petroleum generation potential and formulate effective exploration strategies.In this study,a comprehensive geochemical analysis was carried out on ten Paleocene rock cuttings extracted from TP-1,a discovery well within the Tano Basin.Various analytical techniques,including total organic carbon(TOC)analysis,Rock–Eval pyrolysis,gas chromatography-mass spectrometry,and isotope ratio-mass spectrometry,were employed to elucidate their hydrocar-bon potential and organic facies.Thefindings in this study were subsequently compared to existing geochemical data on Paleocene source rocks in the South Atlantic marginal basins.The results indicated that the Paleocene samples have TOC content ranging from 0.68 to 2.93 wt%.The prevalent kerogen types identified in these samples were Type Ⅱ and Type Ⅲ.Molecular and isotope data suggest that the organic matter found in the Paleocene mudrocks can be traced back to land plants and lower aquatic organisms.These mudrocks were deposited in a transi-tional environment withfluctuating water salinity,charac-terized by sub-oxic redox conditions.Maturity indices,both bulk and molecular,indicated a spectrum of maturity levels within the Paleocene mudrocks,spanning from immature to marginally mature,with increasing maturity observed with greater depth.In comparison,the organic composition and depositional environments of Paleocene source rocks in the Tano Basin closely resemble those found in the Niger Delta Basin,Douala,and Kribi-Campo Basins,the Kwanza Formation in Angola,and certain Brazilian marginal basins.However,it is worth noting that Paleocene source rocks in some of the basins,such as the Niger Delta and Brazilian marginal basins,exhibit rela-tively higher thermal maturity levels compared to those observed in the current Paleocene samples from the Tano Basin.In concl

关 键 词：Paleocene source rocks Source input Depositional environment Thermal maturity Hydrocarbon potential Tano Basin West Africa 

分 类 号：P534.612[天文地球—古生物学与地层学] P597[天文地球—地质学]