Browsing by Author "Jimoh, AY"
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Item Characterization of Petrophysical Properties of Reservoirs in Bima Formation, Northeastern Nigeria: Implication for Hydrocarbon Exploration(Department of Geology School of Physical Sciences, Federal University of Technology, Minna, 2021) Omolaiye, GE; Ajadi, J; Olatunji, S; Jimoh, AY; Ubulom, DENCharacterization of petrophysical properties of reservoirs in Bima Formation was undertaken to understand their spatial distribution and impacts on hydrocarbon saturation in the highly heterolithic siliciclastic sequence. The study was carried out using nine well logs from Maiduguri and Baga/Lake sub-basins within the Borno Basin. Evaluation of the formation reveals largely undifferentiated to highly serrated and lenticular sand bifurcated by shale beds, which reduced their thicknesses variably from 0.61 to 6.1 m. The shale content in the sand bodies ranged from 11.00% to 88.00%. The formation also has variable porosity values, with calculated total porosity ranged from 10.00% to 35.00%. Similarly, effective porosity values spanned between 2.00 to 24.00%. The irregular porosity values also accounted for a wide range of field average permeability estimates computed for the formation, which measured between 0.03 to 319.49mD. Hydrocarbon saturation also varied from 40.00 to 78.00%. Gas accumulation was encountered in Ga-1, Da-1, Ar-1 and Ye-1 wells. These highly thin serrated sand beds with variable porosity and permeability constitute exploration challenges. The very thinly laminated or serrated alternation of sand and shale beds lithofacies of the Bima Formation is supportive of fluvio-lacustrine depositional environments.Item Velocity Analysis for Depth Conversion: A Case Study of Block A, Baga/Lake Sub-basin in the Borno Basin, Northeastern Nigeria(Department of Geology School of Physical Sciences, Federal University of Technology, Minna, 2021) Omolaiye, GE; Olatunji, S; Ajadi, J; Jimoh, AYTime-depth conversion analysis of time-migrated seismic images was undertaken on Block A, Baga/Lake sub-basin of Borno basin Nigeria, to predict the appropriate velocity model suitable for depth conversion away from six existing well control points. Three velocity models were used for the time-to-depth conversion including the average velocity-time analytical function, 2nd Order Polynomial time-depth analytical function, and instantaneous velocity analytical function. The velocity models were tested with the shallow and deep horizons representing the tops of Kerri-Kerri and Gongila Formations penetrated by six wells fairly spread on the 3,891 km? of 3D seismic data. The results show that each model has a variable degree of accuracy after depth conversion at the two formation tops. The average velocity-time analytical technique appeared as the best technique for the time-depth conversion having errors in the range of -0,12 to 145 meters at shallow and deeper formations respectively. The 2nd-order polynomial time-depth analytical function and Vo-K techniques gave a depth uncertainty greater than 135 meters at the shallow formation and over 1,000 meters at the deeper formation. The maximum percentage error recorded for both formations using the average velocity technique was 0.48% this is less than 5% and considered good in the practical situation, it is therefore recommended to be used for velocity modeling and depth conversion study in the Baga/Lake sub-basin of Borno Basin, Northeastern Nigeria.