Method and apparatus for controlling flow of well fluids

Claim 1

IN A MULTIPLE PHASE CYCLIC IN SITU COMBUSTION SUBSURFACE FORMATION STIMULATION METHOD UTILIZING TWO SPACED-APART PIPE STRINGS EXTENDING FROM THE EARTH''S SURFACE DOWNWARDLY IN A WELL BORE; A PACKER ARRANGED IN SAID WELL BORE ABOVE SAID SUBSURFACE FORMATION AND CLOSING OFF THE SPACE BETWEEN SAID PIPE STRINGS AND THE WALL OF SAID WELL BORE; FIRST VALVE MEANS ARRANGED IN ONE OF SAID PIPE STRINGS ABOVE SAID PACKER AND MOVABLE BETWEEN ONE POSITIOP WHICH ESTABLISHERS A FIRST FLOW PATH BETWEEN THE SURFACE OF THE EARTH AND SAID FORMATION ISOLATED FROM THE SPACE SURROUNDING SAID PIPE STRINGS ABOVE THE PICKER AND EXTENDING THROUGH SAID PACKER, SAID FIRST VALVE MEANS AND SAID ONE PIPE STRING, AND ANOTHER POSITION WHICH PREVENTS FLUID COMMUNICATION BETWEEN SAID FORMATION AND THE EARTH''S SURFACE THROUGH SAID PACKER AND SAID FIRST VALVE MEANS BUT WHICH ESTABLISHES A SECOND FLOW PATH BETWEEN THE EARTH''S SURFACE AND THE SPACE SURROUNDING SAID PIPE STRINGS ABOVE SAID PACKER THROUGH SAID FIRST VALVE MEANS AND SAID ONE PIPE STRING; MEANS LOWERABLE THROUGH SAID ONE PIPE STRING FOR MOVING SAID FIRST VALVE MEANS FROM ITS ONE POSITION TO ITS OTHER POSITION AND VICE VERSA; AT LEAST ONE SECOND VALVE MEANS ARRANGED IN SAID OTHER PIPE STRING ABOVE SAID FIRST VALVE MEANS AND MOVABLE BETWEEN ONE POSITION WHICH PREVENTS FLUID COMMUNICATION BETWEEN THE INTERIOR OF SAID OTHER PIPE STRING AND THE SPACE SURROUNDING IT AND ANOTHER POSITION WHICH ESTABLISHES A THIRD FLOW PATH BETWEEN SAID FORMATION AND THE SPACE SURROUNDING SAID PIPE STRINGS ABOVE SAID PACKER THROUGH SAID OTHER PIPE STRING AND SAID SECOND VALVE MEANS; AND MEAN LOWERABLE THROUGH SAID OTHER PIPE STRING TO A POSITION ADJACENT SAID FORMATION FOR MOVING SAID SECOND VALVE MEANS FROM ITS ONE TO ITS OTHER POSITION AND VICE VERSA, THE STEPS COMPRISING: POSITIONING SAID FIRST VALVE MEANS IN ITS POSITION; INJECTING AIR FROM THE EARTH''S SURFACE INTO SAID FORMATION ALONG SAID FIRST FLOW PATH TO INITIATE AND MAINTAIN IN SITU COMBUSTION FOR A SELECTED TIME; TERMINATING SAID INJECTION OF AIR AFTER SAID SELECTED TIME TO COMPLETE THE COMBUSTION PHASE; PRODUCING OIL FROM SAID FORMATION TO THE EARTH''S SURFACE ALONG SAID FIRST FLOW PATH UNTIL PRODUCTION CEASES; POSITIONING SAID FIRST VALVE MEANS IN ITS OTHER POSITION TO ESTABLISH SAID SECOND FLOW PATH; POSITIONING SAID SECOND VALVE MEANS IN ITS OTHER POSITION TO ESTABLISH SAID THIRD FLOW PATH; AND PUMPING OIL TO THE EARTH''S SURFACE FROM ADJACENT SAID FIRST VALVE MEANS, SAID HYDROCARBONS PRODUCED FROM SAID FORMATION FLOWING UPWARDLY THEREFROM THROUGH SAID THIRD FLOW PATH INTO THE SPACE SURROUNDING SAID PIPE STRINGS ABOVE SAID PACKER WHERE GAS SEPARATES FROM OIL, THE GAS FLOWING UPWARDLY THROUGH THE ANNULUS BETWEEN SAID OTHER PIPE STRING AND THE WELL BORE WALL TO THE EARTH''S SURFACE AND THE OIL FLOWING FROM SAID THIRD FLOW PATH INTO SAID SECOND FLOW PATH AND, THENCE, UPWARDLY TO THE EARTH''S SURFACE.