1D Pore Pressure and Geomechanics Models for Infill Well Drilling Optimization in CN Field, Offshore Niger Delta

One of the significant challenges of hydrocarbon exploration especially in drilling campaigns is inaccurate well placement, leading to drilling unproductive wells and economically unviable opportunities in globally recognized petroleum-rich basins especially in our Niger Delta Basin, where since the effect of out-break of the global pandemic, drilling activities has decreased because of a whole lot of challenges. It is therefore of paramount importance to understand subsurface behaviour in planning wells, especially in a tectonically complex environment. The objective of the study is to employ pore pressure analysis and using geomechanics to evaluate wellbore stability in predicting mud-weight window and incorporating best practicing for accurate well placement to ensure minimum drilling risk and further reducing non-productive time (NPT). The workflow exploited five (5) parent wells investigating for the cause of overpressure in the field, building NCT and Overburden models, before estimating P10, P50, and P90 pore pressure models for the field. These models were also instrumental in estimating collapse pressure, shear failure gradient, maximum horizontal stress (SHmax) and fracture pressure/minimum horizontal stress (Shmin). From the offset wells using empirical relations suited for the field, 1D geomechanical model was constructed resulting in poisson's ratio (PR), unconfined compressive stress (USC), and friction angle (FA). Results from the pore pressure and geomechanics models informed our mud-weight selection, and to analyze wellbore strength prior to troublesome intervals. The mohr coulomb plot investigated the region of stability using the principal stresses, which revealed that at the understudied depths the well will not fail, further boosting our drilling confidence. From the study, the model boosted the analysis of the bedding plane failures, integrating a simulation of the existing stress profile. The analysis revealed the optimum mud-weight required to drill especially in reservoir depleted intervals. Consequently, future well placement and drilling can be done with minimal damage to the reservoir with negligible significance to wellbore instability concerns.