Structural Discontinuities and Fault-Induced Reservoir Compartmentalization in the QUAC Field, Niger Delta, Nigeria

Faults play a crucial role in subsurface reservoir characterization by influencing fluid migration, compartmentalization, and hydrocarbon trapping. Understanding fault-induced variations in petrophysical properties is essential for optimizing reservoir management and hydrocarbon recovery. This study investigates the structural discontinuities in the subsurface through well log analysis of three wells QUAC-1, QUAC-2, and QUAC-3. It aims to delineate fault zones and assess their impact on lithology, porosity, and fluid distribution. Gamma ray (GR), resistivity, density, neutron porosity, and sonic logs were analyzed across the three wells. Key fault indicators were identified using abrupt log variations, lithological shifts, and crossplot analyses. Fault types were classified based on stratigraphic displacement and structural interpretation. Five fault zones (F1–F5) were identified, with F1 and F3, classified as major faults unlike F2, F4 and F5. GR variations indicated shale smearing along fault planes, while resistivity contrasts revealed compartmentalization effects. Density-neutron crossover effects suggested gas-bearing zones displaced along fault planes, confirming hydrocarbon migration pathways. The findings highlight fault-controlled lithological variations and reservoir compartmentalization, with normal faults predominantly influencing the study area. Reservoir quality is impacted by fault juxtaposition, affecting hydrocarbon accumulation and fluid flow. Structural discontinuities significantly influence reservoir characterization. Identifying and quantifying fault effects is crucial for improving exploration strategies and enhancing hydrocarbon recovery. This study integrates petrophysical log correlations to refine fault classification and assess their impact on reservoir compartmentalization, providing insights into hydrocarbon prospectivity in structurally complex formations.