Hydrocarbon generation potential of Campano-Maastrichtian to Paleogene shales in the Benin Flank of the Anambra Basin,SW Nigeria  

作　　者：Omabehere Innocent Ejeh Israel Aruoriwo Abiodun Etobro Konstantinos Perleros Jude Etunimonuwa Ogala Ajayi Olugbenga Ehinola Kimon Christanis Stavros Kalaitzidis 

机构地区：[1]Department of Geology,Delta State University,Abraka,Nigeria [2]Geo-Energy Resources Team,Laboratory of Economic Geology,Department of Geology,University of Patras,Rio-Patras,Greece [3]Department of Geology,University of Ibadan,Ibadan,Nigeria

出　　处：《Energy Geoscience》2024年第3期103-116,共14页能源地球科学（英文）

摘　　要：The hydrocarbon generation potential of the Campano-Maastrichtian to Paleogene shales from the Benin Flank(located in SW Nigeria)of the Anambra Basin,has been previously investigated mostly by studying outcrops and by relatively few subsurface data-based studies.Thus,it is expedient undertaking an assessment of the hydrocarbon generation potential of this frontier area from subsurface samples.Campano-Maastrichtian to Paleogene shale samples obtained from Egoli-1 borehole in the Benin Flank of the Anambra Basin are studied by means of HAWK programmed pyrolysis,organic petrography,and mineralogy(XRD),with the aim to explore the petroleum-generating potential and the thermal maturity.The obtained results display a significant variation of the TOC content ranging from very low(<0.5%)to significant(>5%),indicating poor to excellent oil potential based on S_(2)values under the condition,of course,the studied formations reached the oil window.The shales of the Nsukka and Imo Formations display lower petroleum-generating potential than these of the Mamu Formation.All the studied samples are dominated by gas-prone(type III)and inert(type IV)kerogens,with few displaying mixed II/III(oil-and gas-prone).The organic-petrography observations support partly the results of the HAWK programmed pyrolysis,as they reveal an organic-richer Mamu Formation in comparison to the Nsukka and Imo Formations;huminite/vitrinite particles(both indigenous and recycled)along with variable contents of liptinite(mostly alginite and bituminite)and inertinite macerals(mostly inertodetrinite)are hosted in the shales.The latter display a typical composition for fine-grained clastic sediments;mostly kaolinite,illite/montmorillonite,quartz,and subordinately,anatase.In terms of thermal maturity,huminite/vitrinite reflectance data points to immature stage;however,the occurrence of solid bitumens,displaying equivalent vitrinite reflectance values within the oil window,points to an active petroleum system in sequences deeper than the examined ones.

关 键 词：MACERAL Mamu Formation Thermal maturity Solid bitumen Source rock Vitrinite reflectance 

分 类 号：P618.13[天文地球—矿床学]