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Abstract
This study has investigated hydrocarbon generation potential for OML 64 in Warri State, Nigeria. Ten (10) core samples collected at stratigraphic depths from four producing fields of the Oil Mining Lease, OML 64 in Warri State were investigated for total organic carbon (TOC), Rock-Eval analysis and vitrinite reflectance. Results have revealed that they have generally high total organic carbon (TOC) contents, suggesting that there exist conditions in the OML64 that favoured organic matter production and preservation. The Rock-Eval results showed that the samples from fields G and H contain predominantly Type I Kerogen with a capacity to generate oil and hence has a good generation potential. The samples from fields E and F contain mainly Type III Kerogen and are gas-prone with a moderate generation potential. From vitrinite reflectance measurements, all the samples from the producing fields E, F, G and H reveal moderate sourcerock grade.
The Agbada Formation can be regarded as having good petroleum source rocks for hydrocarbon generation and could be part of a petroleum system (geologic components and processes necessary to generate and store hydrocarbons, including a mature source rock, migration pathway, reservoir rock, trap and seal) if sufficient burial and maturation have occurred.
Keywords: Warri State, hydrocarbon generation potential, total organic carbon, rock-eval pyrolysis, vitrinite reflectance.
1.Introduction
The Niger Delta Basin, located on the western edge of the African continent and southern part of Nigeria, covers an area of 75,000 km2 and consists of 9000-12,000 m of clastic sediments (Ojo et al. 2012; Aminu and Oloruniwo 2012). The Niger Delta Basin is divided into five depobelts namely: Northern Delta, Greater Ughelli, Central Swamp, Coastal Swamp and Offshore depobelt. The present study area lies in the Northern Delta depobelt considered the oldest and as one of the productive hydrocarbon depobelt in the Niger Delta Basin. It has substantial hydrocarbon potential as oil and condensate discoveries have been reported (Esedo and Ozumba 2005; Avuru et al. 2011). Published reports on geochemical attributes, burial histories and hydrocarbon generation phases of potential source units in the Northern Delta depobelt have been suggested. The oil and gas accumulated in the late Eocene-Oligocene Agbada Formation, while the source rock intervals are interbedded organic shales within the paralic Agbada Formation.
According to Dembicki (2008), source...