Evenly distributed production along the length of the wellbore is important for maximizing the oil recoverables over the life of the well. Traditional, passive in-flow control devices (ICDs) perform well at balancing the completion pressure differential with the reservoir pressure differential so that an even influx across production zones is maintained. This helps to delay unwanted fluid break through. When unwanted fluids, typically of lower viscosity, do finally break through, they can take over the well, significantly reducing the production of oil. Autonomous Inflow Control Devices (AICDs) are a new generation of ICDs. When oil is producing from all zones, the AICD will behave as a passive ICD, balancing flow. However, when lower viscosity (undesired) fluids break through, the AICD chokes them, significantly reducing flow from the zone producing these fluids. This autonomous function enables the well to drain the oil producing zones faster than the undesirable fluid zones, thereby maximizing total oil production. The AICD creates this change in behavior without control lines, moving parts, or electronics.
The paper describes the laboratory testing performed to evaluate the performance of the fluidic diode type AICD Range 2A in field-like conditions and compares flow performance curves to a traditional nozzle type ICD. The AICD Range 2A utilizes similar fluid vectoring as the Range 3B (Least et al, 2013), but includes more of an autonomous on/off type switching function instead of a gradual change in performance. The range 2A is currently best suited for oil viscosities of 1.5-10 cP. Results from single-phase experimental flow testing with model oil, water, and nitrogen are presented and discussed.
The test results demonstrated that the AICD could restrict flow rates of undesirable fluids. The discussion further shows that if technology such as the new AICD is applied to new well completion designs, total oil recovery can be enhanced, by increasing the life of the well and reducing production of undesirable fluids.