Bulk geochemical parameters and biomarker characteristics of organic matter in two wells (Gaibu-1 and Kasade-1) from the Bornu basin: Implications on the hydrocarbon potential

摘要

Ditch-cutting samples from two exploratory oil wells in the Bornu basin namely Gaibu-1 and Kasade-1 were analyzed using organic geochemistry, and petrology as well as biomarkers. Two potential gas source intervals (1120- 1180m and 1285-1405 m) with the possibility of an oil source at about 1300 m depth are found within the Fika-Gongila lithology in Kasade-1. Although potential source rock is present in the Kasade-1 well, these intervals are too shallow for significant gas generation. No potential gas/oil source intervals were encountered in the Gaibu-1 well. However in this well, vitrinite reflectance values range from 1.17 to 1.45% indicating maturity in the oil to gas window.This study like similar earlier ones has found the Chad basin to have hydrocarbon generation and accumulation potential. The Fika and Gongila Formations have generally TOC >0.5 wt.%, the minimurn content for hydrocarbon generation. Potential reservoir rocks are the Bima Sandstones. The shale intercalations within this formation could serve as seals or cap rocks.More wells are to be investigated together with the application of a 3D seismic technique in order to have a better knowledge of the subsurface geology of the Bornu basin. This may lead to a final decision on the petroleum prospects of the basin.