Paleo-productivity and petroleum source evaluation of the Nkporo and Awgu shales, Lower Benue Trough, Nigeria: Insight from inorganic geochemistry

查看全文 作　　者：Henry Yemagu [1]Madukwe;Adebanji Kayode [2]Adegoke;Mutiu Adesina [3]Adeleye;Adeyinka Oluyemi [1]Aturamu 机构地区：[1]Department of Geology,Faculty of Science,Ekiti State University,P.M.B.5363,Ado-Ekiti,Nigeria;[2]Department of Geology,University of Malaya,50603,Kuala Lumpur,Malaysia;[3]Department of Geology,Faculty of Science,University of Ibadan,Ibadan,Nigeria 出　　处：《Energy Geoscience》索引2023年第4卷第3期,共10页 摘　　要：The petroleum paleo-productivity and generative potential of the Nkporo and Awgu shales in the Lower Benue Trough (LBT) were studied. Major oxides were determined using Spectro Ciros Inductively-coupled plasma optical emission spectrometer (ICP-OES) while trace and rare earth elements were determined using an ELAN 9000 Inductively-coupled plasma mass spectrometer (ICP-MS). The shales have Co/Ni ratios greater than 0.1 suggesting oil source rocks with more marine source input due to brief marine incursion in the transition zone after deposition. The very low Ni values and moderate V values, and a lack of correlation between the TOC and sulphur content, suggests that the organic matter is of terrestrial Type Ⅲ;and the very low paleo-productivity (Ba/Al and P/Ti ratios) suggests that the organic matter is of terrestrial origin. The low V/Ni values of the Nkporo and Awgu shales (Av. ≈ 4) and the high metal concentrations indicate a matured status. From the K/Rb ratios of the Nkporo (191–259) and Awgu shales (198–261), it can be deduced that the organic matter within the shales experienced a considerable loss of K and the shales are mature to generate gaseous hydrocarbons. 关 键 词：MATURITY Organic matter Paleo-productivity Petroleum potentials SHALE