Intelligent field (aka I-field, digital field, smart field) is one of the most important and interesting topics in production engineering. The core elements of the intelligent fields are intelligent wells (aka I-wells, smart wells). I-wells are equipped with downhole devices providing monitoring and control capabilities of different zones. While real-time downhole monitoring provides detailed information and help to identify the inflow or outflow problems, the flexible control will optimize the production and increase the recovery. From the application point of view, the primary aim of the I-wells was to reduce the number of wells and interventions required. But the technology’s true promise is best realised when the I-well changes its identity from intervention avoidance to a reservoir management tool. I-well enables the operators to monitor and control the zonal phase production to optimise the current production and enhance reserve recovery. The recent developments in technology (e.g. downhole permanent pressure and temperature sensors) improved the accuracy and enhanced the application of I-wells. The following are categories where I-wells can provide added-value comparing to conventional wells: