Mitigating Early Water and Gas Breakthrough: Autonomous Inflow Control Valve Applications in the Balder Field

Abstract

Summary The Balder field is typically completed with long, horizontal wells. In the initial development of the field the wells were typically completed with stand-alone screens (SAS), in later developments they were completed with nozzle inflow control devices (ICD), and recently with autonomous inflow control devices (AICD) to mitigate early water breakthrough. The purpose of this study is to assess the implementation of autonomous inflow control valves (AICV) to further mitigate unwanted fluid production and enhance the long-term oil recovery in the field. The study employed numerical reservoir simulation tools and static wellbore simulators to model the Balder field. Simulations were performed both on a sector model around the target well, to reduce simulation time, and on the full-field reservoir model. Two different dynamic reservoir simulators were used. Reservoir simulation tools were used to compare a base case scenario of SAS completion with AICVs. AICV wells require proper compartmentalization, and 3, 5, and 7 compartment scenarios were considered. Simulation results show how the AICV completion retains the reservoir pressure in the initial years of production compared to the SAS. This leads to a significant reduction in early gas breakthrough, reducing the overall gas production. Moreover, the water production after breakthrough was also reduced. Water and gas production is reduced more by having more compartments, which indicates that proper isolation of the wellbore is key to optimize the production of a well. The simulation results from a hydrodynamic sector model aligned with the full field model, and the near wellbore model reproducing observed pressure drop across the AICVs assessing the robustness of the workflow for device modeling in simulators. The study provides a workflow for performing dynamic reservoir simulations using AICV completion. It covers how compartmentalization affects the overall productivity of a well, and how AICVs work for optimizing the inflow from the reservoir to an oil well. Moreover, the study analyzes the impact of the reservoir model grid size on the lower completion evaluation. Important design decisions are based on physics in the reservoir and can be applied to other fields.