This paper discusses a new generation of inflow control devices (ICDs), which are known as autonomous inflow control devices (AICDs) that can balance production flow and restrict the unwanted fluid. This paper describes the functional testing conducted to evaluate the performance of the fluidic diode type AICD for oil conditions of less than or equal to 1.5 cP and the restriction of unwanted gas in field-like conditions. It will also compare flow performance curves to those of a traditional nozzle-type ICD.

Unbalanced inflow from a reservoir can result in water or gas breakthrough, and unless this situation can be addressed satisfactorily, valuable reserves may be lost. When oil is producing from all zones, the AICD will behave as a passive ICD, thereby balancing flow. However, when lower-viscosity fluids break through, the AICD provides a choking effect, significantly reducing flow from the zone responsible for producing these undesirable fluids. Such autonomous characteristics enable a higher recovery rate of oil and also reduce the cost for processing the unwanted fluids. The AICD creates this change in production performance without control lines, moving parts, or electronics.

The AICD presented in this paper, also known as Range 1, has an innovative fluidic sensor that is highly sensitive to the fluid properties and is currently best suited for oil viscosities of 0.3–1.5 cP. The Range 1 AICD uses an autonomous on/off type switching function upon gas breakthrough to control gas inflow instead of a gradual change in total flow performance as provided by other inflow control device types. Oil flow is fed directly to the exit port of the AICD, while gas is "switched" to a highly restrictive, spinning path that limits gas production through the tool. Results from single-phase experimental flow testing with oil and nitrogen are presented and discussed. The test results demonstrate that the AICD is an effective tool for restricting gas production.

The discussion further shows that if technology, such as the new AICD, is applied to a well-completion design, total oil recovery can be enhanced by increasing the life of the well and reducing the production of undesirable fluids.

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