A VALVE FOR CLOSING FLUID COMMUNICATION BETWEEN A WELL AND A PRODUCTION STRING, AND A METHOD OF USING THE VALVE

A valve is for closing fluid communication between a horizontal or deviated well and a production string when a content of a first or a second undesired fluid in the fluid flow exceeds a predetermined level. The valve has a primary flow channel, and a piston arrangement movable within the valve between an inactive position allowing fluid flow through the primary channel and an active position preventing fluid flow through the primary channel. The piston arrangement further has a secondary flow channel and a bypass flow channel and inflow control elements exposed to the fluid flow upstream of the flow barrier and having different density and movable within independent paths in response to a density of fluid.