Abstract: Methods and apparatus for isolating the producing zone of a well during workover operations, particularly where the well is equipped with a production string and a submersible electric pump suspended thereon. A packer and isolation valve are set in the well above the producing zone, and a hydraulically operable control suspended on the pipe string below the pump is releasably coupled to the valve and arranged to enable remote control of the valve from the surface by adjusting the pressure of fluids in the production string or in the well annulus.