Gas lift mandrel valve mechanism

Abstract

A mandrel valve and gas lift valve mechanism that is adapted to be interconnected in a production tubing string within a well in order to produce fluid from the well under conventional gas lift methods. A plurality of gas lift valve mechanisms, which may be referred to as mandrel assemblies, may be dispersed or spaced in accordance with any suitable gas lift system design or, if desired, may be connected in end-to-end relationship defining a cluster of gas lift valves at each of several levels within the well. Each of the mandrel assemblies may include a gas lift valve and a mandrel valve that function to produce fluid only when the mandrel valve is open. Certain ones of the mandrel valves may be maintained in the open condition thereof while others of the valves may remain selectively closed during production operation. Selective opening and closing of the mandrel valves may be accomplished to modify gas lift operations or eliminate defective gas lift valves without necessitating removal of the tubing string from the well. A mandrel valve housing is provided on the outer portion of the mandrel with a valve chamber defined within the housing being disposed in fluid communication with the mandrel by means of an elongated opening. An elongated mandrel valve element is movable between open and closed positions within the valve chamber to allow the flow of gas through the mandrel valve structure into the tubing portion of the mandrel, such valve movement being induced by a valve actuating sleeve movably disposed within the mandrel, which is mechanically connected with the mandrel valve element by way of a projection carried by the mandrel valve element and extending through the elongated opening. A movable seal and a stationary seal are positioned within the valve chamber with the stationary seal being bridged by a flow passage in the mandrel valve element upon movement of the mandrel valve element to the open position thereof.