QUANTITATIVE CHARACTERIZATION OF SHALE VOLUME AND ITS ROLE IN RESERVOIR PERFORMANCE: A PETROPHYSICAL CASE STUDY

This study examines the quantitative estimation of shale volume (Vsh) and its impact on reservoir performance in Field 'Z', Niger Delta, using data from wells Z-005, Z-006, and Z-007.The objective was to evaluate the relationship between shale content and key petrophysical parameters-effective porosity, permeability, and hydrocarbon saturation-and their influence on production efficiency.Shale volume was determined from gamma ray analysis and density-neutron crossplots, while porosity and permeability were derived from well log data.Results reveal an inverse relationship between shale content and reservoir quality.In well Z-005, zone R2 exhibited low Vsh (0.12), high porosity (0.27), and good permeability (28.64 mD), indicating excellent reservoir potential.Conversely, well Z-006 in zone R4 had high Vsh (0.28) with reduced porosity (0.19) and permeability (12.36 mD), reflecting poor flow capacity.Similarly, well Z-007 recorded clean sands (Vsh 0.10) with favorable porosity (0.24) and permeability (25.12 mD).Cross-well correlation and spatial distribution maps confirmed lateral continuity in clean zones, while heterogeneous shale distribution created stratigraphic complexities.Overall, shale volume above 0.25 correlated with poor reservoir quality.The study recommends prioritizing zones with Vsh < 0.20 for completions and applying 3D modeling to enhance prediction of reservoir performance.