Autonomous Inflow Control Valve for Ultra-Light Oil and the Impact of Annulus Phase Segregation

Abstract Autonomous inflow control valve (AICV) can make better and more carbon efficient oil wells. This paper publishes new experimental data for how an AICV handles ultra-light oil (0.8 centipoise), water and gas at full reservoir conditions. The paper also evaluates how phase segregation in the annulus outside the sand screens impact the effective zonal performance, and finally the impact of the tested valve on a typical thin oil rim infill target. To verify the single and multi-phase flow behaviour of the AICV, a full-scale flow loop test was performed at down hole conditions. To understand and estimate the effective performance of several AICVs in wells with open annulus outside the sand screens, a newly developed lower completion modelling tool was used. The model includes phase segregation for a given well geometry and boundary conditions, and the result is integrated into industry standard reservoir simulators. Both the tested valve and an inflow control device (ICD) of similar choke strength as the AICV are "zonally upscaled" and evaluated for several infill well scenarios. At various differential pressure the single- and multi-phase flow of oil, water, and gas rates were measured. The results show an AICV with high capacity for oil, while it chokes hard on both gas and water. The valve's performance was matched by the extended RCP function. The new lower completion modelling software calculates effective zonal performance accounting for phase segregation effects. As compared to the individual AICV performance, the effective zonal AICV-ensemble chokes harder for multi-phase flow. For the ICD's, the effective zonal performance change is opposite, with less choking at multi-phase flow. The effective zonal performance of the ICD-ensemble is well matched by the extended RCP function. The effective zonal performance of the AICV-ensemble cannot be matched by the same function, and a solution is to export the result as a pressure drop table. Test cases demonstrate the correctness of both methods. The infill well scenarios are inspired from a Norwegian oil field with thin oil rims and ultra-light oil. When compared with an ICD well, the well with AICVs reduce water production and increase oil recovery in all scenarios. New experimental AICV performance data for ultra-light oil (0.8 centipoise) at full reservoir conditions is published here for the first time. Further, a new lower completion modelling method that accounts for phase segregation in the annulus outside the sand screens is used in this study. This gives new insight to the effective zonal performance of both ICDs and AICVs and improves the production forecasts from wells with such technology.