the outer production tubular 110 and casing 102 it may be used for controlling pressure in this region and or for circulating treatment fluids to service the well fig2 a and 2b show a detail view of the outer and inner production tubulars 110 114 termini as well as the check valve 112 that terminates the outer tubular 110 the check valve 112 takes the form of a ball and seat valve during the intake phase shown in fig2 a the pressures on either side of the check valve 112 are balanced enabling the formation fluid 104 to raise the ball 140 and flow inside the lower end of the inner and outer tubulars during the injection phase shown in fig2 b the surface unit 118 injects cng via the annular conduit the increase in pressure forces the ball 140 onto its seat preventing the fluid from escaping instead the fluid is forced into the central conduit and lifted by the gas pressure to the surface and into the storage tank once the bulk of the fluid has been cleared from the central conduit the pressure drops rapidly and the gas injection ceases until a sufficient amount of fluid has accumulated for the process to be repeated in this embodiment it is contemplated that the gas injection is performed quickly at high pressure to lift the accumulated formation fluid as one or more large slugs u201c slug flow u201d.