Combination in situ combustionwaterflooding process

Claim 1

IN THE PROCESS FOR THE RECOVERY OF PETROLEUM FROM A RESERVOR BY DRIVING SAID PETROLEUM WITH WATER, SAID RESERVOIR BEING PENETRATED BY AN INDJECTION WELL AND A PRODUCTION WELL, THE IMPROVEMENT WHICH COMPRISES: FIRST SHUTTING IN SAID PRODUCTION WELL, INJECTING AN OXYGEN-CONTAINING GAS INTO SAID RESERVOIR VIA SAID INJECTION WELL UNTIL THE PRESSURE OF SAID GAS IN SAID RESERVOIR IS AT LEAST ABOUT 500P.S.I.; BUT LESS THAN THAT REQUIRED TO CAUSE UNCONTROLLED FRACTURING THERE OF, THEREAFTER IGNITING THE PETROLEUM IN SAID RESERVOIR AT THE FACE THEROF IN SAID INJECTION WELL TO FORM A COMBUTION FRONT, NEXT ALLOWING SAID GAS TO BACKFLOW THROUGH SAID RESERVOIR AND INTO SAID INJECTION WELL AND COUNTERMOVE AWAY FROM SAID INJECTION WELL AND COUNTERCURRENTLY TO SAID BACKFLOW, SAID BACKFLOW BEING AT A FLUX SUFFICENT TO PRODUCE A RESERVOIR TEMPERATURE OF AT LEAST ABOUT 700*F., OPENING SAID PRODUCTION WELL WHEN SAID BACKFLOW FALLS BELOW SAID FLUX, FLOODING SAID RESERVOIR BY ADDING WATER THERETO VIA SAID INJECTION WELL WHEREBY A PORTION THEREOF IS CONVERTED INTO STEAM RESULTING IN DRIVING PETROLEUM THROUGH SAID RESERVOIR TOWARD AID PRODUCTION WELL, AND RECOVERING OIL FROM SAID PRODUCTION WELL, THE HEAT IN SAID RESERVOIR RESULTING FROM THE ABOVE-MENTIONED COMBUSTION STEP BEING SUFFICIENT AROUND SAID PRODUCING WELL SO THAT WATER FLOWS INTO SAID PRODUCING WELL SUBSTANTIALLY AT ITS BOILING POINT.