This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 173203, “Optimized Design of Autonomous Inflow-Control Devices for Gas and Water Coning,” by Terry W. Stone, Terje Moen, David A. Edwards, Alexander Shadchnev, and Kashif Rashid, Schlumberger, and Geir Frode Kvilaas and Kjell Christoffersen, Det Norske Oljeselskap, prepared for the 2015 SPE Reservoir Simulation Symposium, Houston, 23–25 February. The paper has not been peer reviewed. Several designs for autonomous inflow-control devices (AICDs) are available. One forces inflowing fluids to enter gates, depending on inertial and viscous forces of the various fluids. Another is an autonomous valve in the shape of a free-floating disk that restricts the flow rate of low-viscosity fluids and is primarily used to choke gas and water inflow. Recently, a device with water-swellable rubber inside the nozzle has been proposed, but it is not yet commercially available. The comparative properties and abilities of these designs are the focus of this paper. Well Model, Reservoir Simulator, and Optimizer The well model used in this work is part of a next-generation parallel commercial reservoir simulator and features a flexible multisegmented well topology, enhanced robustness for difficult problems, and extensive well-model options. It forms part of a scalable parallel commercial reservoir simulator. Optimizations carried out in this work used an optimizer developed to alleviate the computational cost in an optimization study where simulation-based objective functions are expensive to evaluate. When compared with several other commonly used optimizers, it was demonstrated that this optimizer outperformed others significantly. Modeling Inflow-Control Devices (ICDs) Various ICD designs include those with nozzle orifices, tubes, and helices. Unlike ICDs, AICDs may or may not have moving parts but they can change or modify their state in response to inflow. Design of the AICD determines the particular unwanted fluids that are delayed. There are a number of types available commercially, including a floating flapper, an oil- selector valve, an autonomous inflow-control valve, the rate-controlled-production (RCP) valve, and a fluidic diode valve. Another design recently proposed is based on inclusion of water-swellable rubber within the nozzle, but this is not yet commercially available. Both ICDs and AICDs are often deployed in a compartment whose edges are sealed with a packer, and are placed in the tubing wall between an annulus and main production stream.