US Patent 11174702 Dual flapper isolation valve

A downhole tool includes an upper flow tube connected to a lower flow tube, an upper flapper sub-assembly including an upper flapper, and a lower flapper sub-assembly including a lower flapper. The upper and lower flapper sub-assemblies are installed with respect to the upper and lower flow tubes in an “O” configuration such that the upper and lower flapper sub-assemblies are in a closed position. The upper and lower flapper sub-assemblies are capable of being independently actuated. The upper and lower flow tubes remain stationary when the upper flapper sub-assembly or the lower flapper sub-assembly is actuated from the closed position to an open position.