Sedimentation, depositional environments, and hydrocarbon potential of the Maastrichtian-Paleocene Araromi Formation, eastern Dahomey (Benin) Basin, southwestern Nigeria

Autor: Oluwajana, O. A., Opatola, A. O., Adamolekun, Olajide Jonathan, Ndukwe, O. S., Olawuyi, G. T., Ofiwe, C. U., Bolaji, T. A., Adebambo, B. A., Oluwajana, O. O.
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Petroleum Exploration and Production Technology, 11, 3917–3934
ISSN: 2190-0558
2190-0566
DOI: 10.5445/ir/1000137488
Popis: The Cretaceous sediments in southwestern Nigeria are host to one of the largest bitumen deposits in the world. In the current paper, an integrated study on sedimentology, palynology, and applied petroleum geochemistry of the Maastrichtian-Paleocene Araromi Formation was used to determine the depositional environments and hydrocarbon potentials of the formation on the eastern Dahomey Basin. Four sedimentary lithofacies were identified from core samples, namely, lower limestone (F$_{1}$); medium to coarse-grained sandstone (F$_{2}$); lower loosely consolidated sandstone (F$_{3}$); and shale and siltstone (F$_{4}$). Sedimentation in the eastern Dahomey Basin occurred mainly in fluvial and shallow-marine (shelf) environments. The palynological assemblages of the Araromi Formation reflect deposition in coastal through brackish water to shallow shelf environment with periods of localized wind-induced storms. The shale and siltstone samples of the Araromi Formation are characterized by total organic carbon (TOC) values of up to 2.50 wt % and S$_{2}$ (hydrocarbon-generating potential) values ranging from 0.26 to 0.70 mgHC/g rock, indicating poor source rocks. Shales show poor quality and thermally immature organic matter at shallow depth and could neither have generated liquid hydrocarbon nor contributed to the heavy oil occurrence on the bitumen and tar-sand belt of eastern Dahomey (Benin) Basin.
Databáze: OpenAIRE
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