one half inch by three eighths inch 316 stainless steel bushing 72a bushing 72a is threadably coupled to a three eighths inch xh nipple 74 which in turn receives check valve 75 at its opposite end such as model number 6f c6l 15s f2 produced by parker hannisin corp of huntsville ala check valve 75 is coupled by a stainless steel three eighths inch npt by one half inch compression connector 76 to a one half inch nylon tubing 78 tubing 78 specially selected for this application preferably has a 500 pound working pressure and is available from imperial eastman corp of manitowoc wisc tubing 78 is preferably fastened at intervals to lift tube 51 by pipeline tape or other fastener to keep the two in close proximity to each other injection tubing 78 extends toward surface 12 fig4 and is coupled to a 90 degree compression coupler 79 which in turn is coupled by a second length of tubing 77 to a second compression coupler 81 threaded to a unique coupler 82 in casing 20 coupler 82 is unique in this application in that it preferably includes a one half inch 3000 pound working pressure collar 83 welded to the inside of a one inch npt by two inch npt forged steel bushing 84 collar 83 is threaded at one end to receive one half inch straight stainless steel compression connector 81 to attach tubing 77 to coupler 82 at the top of well 10 seen in fig2 injection assembly 70 is.