TITLE:
Possible Bornu Basin Hydrocarbon Habitat—A Review
AUTHORS:
John Adeyinka Adekoya, Peter Sunday Ola, Solomon Ojo Olabode
KEYWORDS:
Organic Geochemistry, Bornu Basin, Source Rock, Reservoir, Trap
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.9,
August
22,
2014
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.