US Patent 10138710 Bidirectional downhole isolation valve

An isolation valve for use in a wellbore includes a tubular housing and an upper flapper disposed in the housing and pivotable relative thereto between an open position and a closed position. An upper piston is operable to open or close the upper flapper. A lower flapper is disposed in the housing and pivotable relative to the housing between an open position and a closed position. A lower piston is operable to open the lower flapper. An opener passage is in fluid communication with the pistons and an opener hydraulic coupling. A closer passage is in fluid communication with the pistons and a closer hydraulic coupling.