Unlocking Sweet Spots Using Reservoir Geophysics Techniques: A Strategy for Well Placement Optimization

Abstract

After integrating a full suite of data to confirm the presence of hydrocarbon-bearing reservoirs, the next critical step towards value realization lies in accurately defining subsurface targets for wellbore placement. Suboptimal well positioning has historically led to significant value erosion—either due to drilling into non-reservoir facies characterized by low porosity and permeability, which hampers sweep efficiency, or, in reservoirs where the water contact has not been properly logged, by placing wells too close to the water contact, resulting in early water breakthrough. This study presents a seismic-driven reservoir characterization approach aimed at identifying sweet spots to enhance well placement decisions. By leveraging advanced geophysical techniques, this strategy improves the precision of target selection, thereby maximizing hydrocarbon recovery and minimizing development risk. The technique centered around building seismic inversion models for predicting reservoir presence and reservoir properties such as porosity. The technique was deployed across a shallow water field in the Niger Delta. Locating reservoirs in this depositional environment can be challenging due to the complex geologic processes responsible for sedimentation. The Seismic inversion model resulted in a robust static and dynamic model. This ultimately formed the basis for optimally locating a planned development well within a sweet spot characterized with good sand development and high porosity. Hitherto, simple geologic model incorporating offset well analysis formed the basis of locating potential drilling target that resulted in suboptimal well location.