Traditionally, first-generation inflow control devices (ICDs) were designed to balance completion pressure differential with reservoir pressure differential so that even flow across production zones could be maintained. The purpose of maintaining even flow was to delay influx of unwanted fluids, and thus, help maximize oil production. However, if low-viscosity fluids were present and did succeed in breaking through, a traditional passive ICD could not control the flow, and the unwanted fluid flow would take over. To provide more effective control in these conditions, a newly developed, autonomous Inflow- control device (AICD) has been introduced to theIndustry. This device will improve production by balancing desired production fluids across the completion, while restricting the production from zones with unwanted fluids. This paper discusses 1) how the AICD detects the fluid properties and 2) how the production of the undesired fluid can be restricted without the use of any moving parts.

The autonomous ICD is designed to function without moving parts, without intervention, without electronics, and without control lines. It is a solid-state design with improved reliability, erosion resistance, corrosion resistance, and plugging resistance that can maintain high mechanical integrity. An autonomous ICD operates by detecting whether the production fluid is undesirable, and then, if unwanted, it restricts the production of the unwanted fluid.

The fluidic diode-type AICD operates using a combination of fluid mechanics, computer modeling, and measured performance data, and this paper explains how these devices are capable of restricting undesirable fluid breakthrough without intervention so that a well can continue to produce the desirable hydrocarbon. Testing procedures and results, which include numerical simulation and experimental testing, also will be presented.

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