One of the challenges in heavy and extra heavy oil production is to improve the recovery and reduce the water cut. A major part of the world's oil reserves is found in heavy and extra heavy oil reservoirs. One of the problems in heavy oil field with water drive or Steam Assisted Gravity Drainage (SAGD) is the mobility ratio. Due to the high oil viscosity the water and/or steam breakthrough will occur after a short time of production. As the breakthrough expands, the production from the well must be choked or stopped due to high water cut. Inflow Control Device (ICD) and Autonomous Inflow Control Device (AICD) may improve the inflow profile along the well. However, neither ICD nor AICD can shut off the unwanted fluid production completely. The Autonomous Inflow Control Valve (AICV) can shut off the unwanted fluid completely and the technology is presented.
The commercial near-well simulation tool, NETool, is used to model and evaluate different scenarios of completion design. Open hole and AICV completion with zonal isolation are compared. A heterogeneous sand stone reservoir with heavy oil and water or gas breakthrough is modeled. The functionality of the AICV, which is to open for oil and close for low viscous fluids as water, steam and gas is modeled by the predefined RCP function. Experimentally determined flow performance characteristics were used to tune the RCP function, and gave a realistic prediction of the AICV behavior. The simulation results show that the completion with AICVs in combination with packers as zonal isolation, reduces the water cut (WC) and gas oil ratio (GOR) significantly. A study of the impact of number of packers i.e. size of the zones, demonstrates that several small compartments is the most robust solution. The water cut will decrease with increasing number of compartments. The inflow profile is more optimal for the AICV completion than for open hole, and shows the ability to enhance drainage efficiency and oil recovery. The importance of gas/water shut off to maintain or increase the oil production at breakthrough is demonstrated.