Petrophysical characterization of the highly heterolithic siliciclastic reservoirs in the Bima Formation was undertaken to determine their spatial spread and its effects on hydrocarbon saturation. The evaluation was done using nine well logs from Lake/Baga and Maiduguri sub-basins in the study area. A combination of log curves was used for the geologic correlation of serrated sand facies and the delineation of lithological heterogeneity of the sand bodies. Interpretation of the well data reveals that the deposition of sediments is in the fluviolacustrine environment which resulted in the alternation of serrated shale and sand bed lithofacies. Analysis of the formation shows mainly undistinguishable to vastly serrated sand bodies, twelve reservoirs were identified and labeled Bima Sand-1 to Bima Sand-12. Intense intercalation of the shale bed and the percentage of shale materials in the reservoirs reduced the thicknesses of the reservoir to between 0.61 and 6.1 m and this has a strong impact on the petrophysical properties. The water saturation (Sw) in the thin serrated sand bodies varied between 22.00 and 60.00% encountered in Ye-1, Da-1, Ga-1, and Ar-1 wells. However, Bima Formation has variable saturation of hydrocarbon, mostly gas in the two sub-basins of the study area. The shale intercalation of thin serrated sand beds, with low effective porosity, and tied with variation in shale contents, have inferences in fluid movement and well perforations, which would pose significant exploitation challenges.