US Patent 11773690 Combined valve system and methodology

A technique facilitates operation of a valve system a having combined valve such as a combined formation isolation valve and a circulating valve. In well operations, the valve system is deployed downhole into a wellbore on a tubing string. The formation isolation valve and the circulating valve are operable independently via inputs, e.g. hydraulic inputs provided through less than three hydraulic control lines. The formation isolation valve and the circulating valve may be coupled by a mechanical linkage, which enables operation of the two valves via the hydraulic control lines. In some embodiments, the formation isolation valve and the circulating valve may be operated via an integrated shifting tool.