Operators in need of improved reservoir drainage, increases in ultimate recovery, and delay of unwanted fluid production are faced with a choice between passive and autonomous inflow control devices (ICD / AICD) to manage these issues most effectively. Production challenges leading to this choice are increasing as water production in particular across the globe continues to rise.
Passive Inflow Control Devices (ICD) have been used with great effect throughout the world. Multiple variants exist using nozzle, tube, or helical designs to balance inflow in long horizontal wells and those with permeability variations. Each type of ICD has various degrees of viscosity insensitivity, with the nozzle-type being seen as relatively viscosity insensitive, which is true when the viscosities of the oil and water are nearly similar. As the viscosities between the two diverge, however, all passive ICD's produce more water than oil at breakthrough for a given pressure.
As ICD's only delay the onset of water and gas breakthrough, however, the industry moved to develop Autonomous ICD's (AICD), which sense the presence of unwanted fluid without any connection to or intervention from the surface. The majority of AICD devices available currently contain moving parts and require close tolerances to deliver their unique benefits. They were initially specifically designed for light oil applications in long horizontal wells to shut off the majority of produced water overall. While this is desirable in low oil viscosity wells it may not be as effective with increases in viscosity due to the need to produce water in order to produce the oil.
The design proposed in this paper uses no moving parts, significantly restricts water production in a wide range of crude viscosities, is easily configured for a variety of downhole conditions, and delivers passive ICD performance with AICD benefits using a simple, reliable, and unique design.
The tool functions to restrict water production progressively as either oil viscosity or water cut increase without ever completely or nearly completely closing to production, which makes it an excellent solution for marginal production wells, younger reservoirs, and wells with lower overall production rates compared to other technologies.
The paper will discuss the theory of the device's functionality to differentiate between fluids present. Laboratory test results will be shown to demonstrate flow performance as well as API 19ICD[1 ] testing for erosion, plugging resistance, and mud flow initiation testing. In addition, an example comparing an open hole base case to the new device's performance in a sample reservoir will be discussed.