Gas drive oil well pumping system having mixing means for the gas/oil mixture

Claim 1

In a gas drive oil well pumping system utilizing gas under pressure to force oil from the well, including a cased well, a production tubing extending longitudinally through the well and cooperating with the casing thereof to define an annulus, means for introducing high pressure gas into the upper end of the annulus, a plurality of jet pump means disposed in longitudinally spaced relation in the tubing and each defining an elongate axially extending venturi, and means communicating with and between the venturi and the annulus to conduct gas from the annulus to said venturi to create suction in said tubing to lift gas and oil from the well in stages, the improvement comprising: a plurality of check valve devices secured in the tubing in spaced apart relation along its length, whereby the gas/oil mixture is lifted in stages from the well, said check valve devices secured in the tubing closely adjacent and upstream of the jet pump means; a central pipe secured inside the tubing immediately upstream and adjacent at least one of the check valve devices and communicating at one end with a check valve device for flow of gas and oil therethrough to the check valve device; and gas/oil mixing devices comprising screen means having apertures therethrough sized to provide a total flow area approximately the flow area of the tubing, said screen means being secured on the other end of the central pipe, for maintaining the oil/gas intermixed and to thus enhance the lifting ability of the gas and thereby increase the efficiency of the system.