Managing Complex Challenges in Reservoir Redevelopment: Case Study of X-Sand in the Niger Delta

Abstract As a field matures with time, it becomes pivotal to leverage on historical production and subsurface understandings to identify further development opportunities. However, there are challenges such as drilling through depleted sands and infill well placement optimization that could impact the success of reservoir redevelopment. The objective of this study was to propose an optimized redevelopment plan via a detailed cross functional subsurface evaluation of a matured reservoir with considerable historical data coverage laden with some challenges such as current contacts, connectivity uncertainty and depleted sands. To achieve the objective, a structured subsurface workflow was utilized to assess the execution feasibility, recovery and challenges associated with the opportunity development. A reservoir simulation model was built, history matched for recovery assessment; Historical contact data tracking was conducted in the simulation model that helped define current contacts and infill wells placement; Subsurface reservoir scenario modelling was conducted to characterized different potential dynamic scenarios in the reservoir. An integrated pore pressure prediction and wellbore drilling evaluation was conducted to identify strategies and manage drilling through depleted sands leveraging technology. Sensitivity runs were carried out to identify optimum production rates and well lateral lengths as well as economic analysis. Study outcomes suggest a proposal of 2 wells (3 completions) to optimally deplete the reservoir of interest in the long term. A detailed Managed Pressure Drilling (MPD) plan was planned and recommended for identified shallow depleted reservoirs during well execution. Study results show robust economics and significant return on investment.