Assessment of Rock Stiffness and Deformability from Dynamic Elastic Properties: A Log-Based Workflow for the Niger Delta Basin

This study evaluates rock stiffness and deformability in the Niger Delta Basin using a log-based geomechanical workflow applied to the WABI Field. Gamma ray and resistivity log correlation identified reservoir intervals in six wells, with sonic data available for two (AKOS-009, AKOS-002). Dynamic elastic parameters—P-wave velocity, S-wave velocity, Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and unconfined compressive strength—were derived from sonic and density logs to characterize mechanical properties. Results show consistent depth-dependent increases in velocities and elastic moduli, reflecting compaction-driven lithification, porosity reduction, and enhanced mechanical competence. Poisson’s ratio decreases with depth, indicating a shift toward more brittle behavior. AKOS-002 displays broader property ranges and greater scatter than AKOS-009, suggesting higher lithological heterogeneity, variable cementation, and differences in consolidation. These variations highlight both regional compaction trends and lateral variability in rock mechanical behavior, with implications for seismic-to-well calibration, fracture prediction, wellbore stability, and reservoir geomechanical modeling.