Evaluation of reservoir quality and hydrocarbon potential in the Kribi Batanga field through logging while drilling insights

Abstract

The Kribi-Campo Sub-Basin offshore Cameroon represents a significant hydrocarbon province; however, exploration success has historically been hindered by persistent uncertainties regarding reservoir heterogeneity and fluid charge. In the Kribi Batanga Field, these challenges necessitate a more robust characterization framework to mitigate subsurface risk and optimize commercial development. We utilizes a high-resolution Logging While Drilling (LWD) suite to conduct a definitive petrophysical evaluation of five identified reservoir intervals (R1–R5). Lithological identification was rigorously established using Matrix Identification (MID) and neutron-density cross-plots to correct legacy interpretations and distinguish true mineralogy from gas-effect anomalies. The workflow integrated Buckles and Pickett plots to assess fluid mobility and irreducible water saturation. The analysis reveals a distinct hydraulic hierarchy among the reservoirs. Reservoirs R2 (Gas) and R4 (Oil) are identified as premium flow units, characterized by effective porosities of 18–20%, permeabilities exceeding 28 mD, and superior hydrocarbon saturations of 68.46% and 54.52%, respectively. High Net-to-Gross ratios (0.74–0.78) further confirm substantial reservoir continuity in these zones. Conversely, Reservoir R1 is classified as a secondary target with high oil saturation (65.37%) but moderate permeability (5.42 mD) requiring stimulation, while Reservoir R3 presents mobile water risks due to a complex oil-gas contact. Reservoir R5 is characterized as a tight, non-pay basal seal with negligible porosity (2.53%). By accurately identifying the formation as a calcite-dominated limestone sequence, this research provides a corrected geological framework that resolves previous lithological ambiguities. The findings confirm the field’s commercial viability and propose a prioritized development strategy that targets the high-quality oil leg in R4 while maintaining the pressure integrity of the R2 gas cap. This LWD-constrained approach serves as a scalable model for reducing uncertainty in similar carbonate-dominated sub-basins globally.