Abstract
An attempt is made in this article to examine and assess the possible petroleum habitat in the Bornu Basin, which is the Nigerian portion of the Mega-Chad Basin that has been found to host oil and gas in commercial quantities in Niger, Chad and Cameroon. The presence of three of the fundamental geological factors (source rock, reservoir rock and seal/trap) for commercial hydrocarbon accumulation was assessed in the light of existing information. Available geochemical information reveals that the shales of the Bima, Gongila and Fika Formations in the Bornu Basin contain sufficient organic matter for hydrocarbon generation. Limited existing geochemical data suggest that the quantity and quality of the organic matter in the shales vary widely with the TOC of most samples ranging from 0.54 wt% - 1.25 wt% and the HI from 11 - 173.80 mg/g in intervals with Tmax in the range of 365°C - 519°C. In addition, the kerogen type is predominantly type III with minor type II, thus suggesting a predominant gas prone basin. Possible reservoir rocks occur as sand/sandstone beds within the Bima, Gombe, and Kerri-Kerri, as well the Gongila Formation which also contains much shale and limestone. Both stratigraphic and structural trapping conditions exist in the Bornu Basin. The structural traps were presumably formed during the widespread Santonian tectonic inversion that affected the entire Mega-Chad Basin. It is suggested that deeper drilling into the sands and sandstone of the untested Bima Formation that could host hydrocarbon of commercial quantities, as evidenced by the discoveries at deeper depths in the neighbouring Termit Basin, was desirable.
Highlights
For commercial accumulation of hydrocarbon to occur in any basin, certain parameters must be available and form an interplay that would create a geological set-up for the formation and entrapment of the hydrocarbon
Several possible reservoir beds exist within the various sand/sandstone units of most the established lithostratigraphic units (Figure 2) in the Bornu Basin except that the orthodox source-reservoir-seal interplay has not been proved. [34] attempted a reservoir characterization and evaluation of depositional trend of sands of Gombe Formation to assess their petrophysical qualities as a potential reservoir unit for hydrocarbon accumulation in the Chad basin because the sand sequence directly overlies Fika Shale—a possible source rock [35] [8] [13] [36]
The foregoing assessment of the potential geological factors that could produce the appropriate petroleum habitat in the Bornu Basin indicates that the ingredients for the formation and retention of petroleum are, by and large, present in the basin
Summary
For commercial accumulation of hydrocarbon to occur in any basin, certain parameters must be available and form an interplay that would create a geological set-up for the formation and entrapment of the hydrocarbon. Prominent among the parameters are source rock, reservoir rock and seal. Accurate assessment of these parameters is important in reducing exploration risk. Exploration work in the Bornu basin had spanned over four decades with fruitless result in spite of major discoveries within the other basins in the Mega-Chad Basin and the West and Central African Rift System (WCARS) in general. Several published reports [2]-[6] have been written on this basin These reports and unpublished ones, including proprietary information, were consulted to achieve our aim. The aim is to assess possible occurrence of fundamental geological parameters for commercial hydrocarbon accumulation and thereafter suggest areas of further research that could serve as guide to subsequent exploratory work in the basin
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
