Indian Journal of Science and Technology Vol. 4 No. 12 (Dec 2011) ISSN: 0974- 6846 `Research article “Hydrocarbon resource in Nigerian Chad basin” Omosanya et al. Indian Society for Education and Environment (iSee) http://www.indjst.org Indian J.Sci.Technol. 1668 The hydrocarbon potential of the Nigerian Chad Basin from wireline logs K.O. Omosanya 1* , A.A. Akinmosin 2 and N.A. Adio 3 1* Department of Earth Sciences, Olabisi Onabanjo University, Ago-Iwoye 2 Department of Geosciences; University of Lagos, Akoka 3 School of Engineering, Faculty of Physical Sciences, University of Aberdeen, United Kingdom kamaloomosanya@yahoo.com * Abstract The need to find an alternative energy source to the Niger Delta has re-enacted interest in the Nigerian Chad (Borno) basin; this work was done in order to evaluate the potential of the basin to generate commercial hydrocarbon. Three (3) Wireline logs from well GUBIO #1, NGAMMA#1 and NGOR#1 of the OPL 419 in the Chad Basin were used for this study. The Gamma ray log, Caliper, Neutron, Density, Sonic, and Resistivity logs were used to identify the reservoir zones (lithology), fractured rock, determine Porosity, identify overpressures zones, and estimate the water and hydrocarbon saturation. In the analysis of the GUBIO#1 well SP and Gamma log were used to predict the environment of the deposition. Fourteen (14), Ten (10), and Eight (8) reservoir zones were delineated for GUBIO #1, NGAMMA#1 and NGOR#1 respectively. With porosity ranging between 4.5-46%, 6-36%, & 2.5-44%, apparent resistivity of 0.0012- 35.52Ωm, 0.02-9.23Ωm & 0.02-26.25Ωm, estimated water saturation (S w ) that lies within 0-35%, 4.9-45.2% & 21-100% for the three wells in that order. The environment of inferred from the SP log shows initial deposition of regressive, and later transgressive to transitional sandstone facies. From this study, the Nigerian Chad basin is a petroleum province with abundant gas than oil and as such can be said to a gas province. Keywords: Nigeria, Chad Basin, Gas, logs, Hydrocarbon, Wireline. Introduction The need to find an alternative energy source to those derived in the Niger Delta has driven renewed government interest and activities in the Nigerian Chad Basin, previous attempt by the E&P companies and the government have not been properly documented. Result from previous workers gave insights to the fact that the basin could be prolific in fact there are very optimistic views on the occurrence of Hydrocarbon within the Nigerian portion of the Chad Basin, especially considering the prolific hydrocarbon plays of the rest of the basin. Good examples include Logone-birni and Boba Basin ESE of the Nigerian Chad Basin and WNW of the Termit basin. Advances in the field of geophysics and geology as a whole had provided the needed impetus to investigate areas that were poorly studied or under- investigated. The rationale behind this work is to provide a new understanding on the hydrocarbon potential of the Nigerian Chad Basin using existing data. Wireline logging techniques entails the investigation of the subsurface i.e. a record of measurement made with depth; because they take a continuous reading of the physical properties of the rock matrix and their pore fluids, they are fundamental to Formation Evaluation. Though logging techniques are widely used in the investigation of boreholes drilled for hydrocarbon exploration, as they provide important in situ properties of possible reservoir rocks they also found use in hydrogeological exploration. Log measurements when properly calibrated, can give the majority of the parameters required by all professional (Geophysicist, Production engineer, Engineers, Manager etc). Quantitative and semi quantitative uses of well logs generally involve all petrophysical and even seismic applications, geological application by defaults are generally qualitative. Utilizing the petrophysical properties of well logs makes it practical to determine the lithology, porosity, shale volume, water and hydrocarbon saturation and type and to estimate permeability, predict water cur, calculate residual oil saturation and detect zones of overpressures. Conversely, geological analysis helps describe the stratigraphy, facies relationship, environment of deposition, structure and fluid properties. This research work is aimed at identifying the possible reservoirs present in each well; determining the hydrocarbon type and saturation; Estimate Porosity of the reservoir zones; quantify the volume of Hydrocarbon in reservoirs, and identify overpressures and compacted shale formation. In achieving these set objectives, this study utilized previous well data acquired by the Nigerian National Petroleum Corporation (NNPC),they are GUBIO #1, NGAMMA#1 and NGOR#1 located within Oil Production license block (OPL) 419 in Longitude 9 o E - 14 o 45 1 E and latitude 10 o 55 1 N-10 o 45 1 N in the Chad (Borno) basin were used for this study. Previous work in the basin include Benkhelil and Robineau (1983), Allix (1983), and Popoff et al. (1986), all interpreting the evolution of the Benue trough and the Chad Basin from geological and structural evidences. The first well drilled in the area, kolami-River-1 by Shell Nigeria Exploration and Production Company (SNEPCO) encountered abundant gas and little oil, subsequent wells were dry. Obaje (2000) and Akande et al. (1998) worked on the source rock characterization of the area with the