mud 104 from exiting from coupling 250 liner 200 prevents spillage of column of drilling fluid or mud 104 from between casing 20 and clamp 160 instead flow of column of drilling fluid or mud 104 is directed from longitudinal passage 186 to valve 240 which can be opened via handle 241 flow will continue through hose 134 pump 130 hose 135 and into receiving tank 120 pump 130 can be used to greatly increase the flow of column of drilling fluid or mud 104 compared to gravity feed of the column after column of drilling fluid or mud is drained recovery tool 10 is removed from casing 20 and casing 20 is cut using casing cutter 400 creating upper section of casing 30 upper section of casing 30 is then removed and lower section of casing 40 is prepared for further work related to oil and gas production while system 10 is shown as being constructed with most elements located below rig floor 17 where tanks 30 and 40 are conveniently out of the way fluid recovery system 10 could also contain one or more tanks above the rig floor or positioned as is convenient for rig conditions the foregoing disclosure and description of the invention is illustrative and explanatory thereof and it will be appreciated by those skilled in the art that various changes in the size shape and materials the use of mechanical equivalents as well as in the details of the illustrated construction or.