Abstract: An isolation valve for a downhole well completion system having a one piece frangible, ceramic sealing element and an extrusion resistant resiliently faced valve seat and a method for the use thereof is presented. Said sealing element is biased to the closed position and rotatable within a sealing element chamber from an open position during run in to a closed position as a result of the withdrawal of a wash pipe and a protector tube from the valve bore. Said frangible sealing element cooperates with said extrusion resistant valve seat to provide a reliable pressure resistant seal. After recovery of completion fluids from the well bore and pressure testing of the production string, the frangible sealing element is shattered by impacting with a tooth-faced blind box hammer.

Abstract: A retrievable packer includes a selectively releasable anti-rotation coupling lug for preventing premature setting of the packer. The lower wedge and packer mandrel are coupled together by the anti-rotation lug during running and setting operations. The anti-rotation lug is slidably received within an L-slot formed in the packer mandrel, and is selectively releasable to permit rotation of the service tool relative to the packer mandrel during retrieving operations. During run-in and retrieving operations, the anti-rotation lug is confined within a circumferentially extending portion of the L-slot, thereby limiting longitudinal travel of the packer mandrel relative to the lower wedge. The service tool can then set down on the packer for pushing the lower wedge out from under the anchor slip.

Abstract: A well system employs a pump to lift liquid through a primary tubing and subsurface safety valve. The tubing passes through a packer and a vent valve vents gas from the well through the packer. The power transfer means may extend through the vent valve and the vent valve may also control a cross-over in the packer for recirculation of liquid to the pump when the well is shut-in. The vent valve has associated therewith a kill valve permitting pumping of kill fluid into the well. The vent remains closed in the presence of ambient pressure up to a selected value and above this value the kill valve opens thus permitting testing of the packer with annulus pressure below the selected pressure and pump through to kill the well with pressure above the selected pressure.