Establishing an inverse burning front without spontaneous ignition

Claim 1

A PROCESS FOR INITIATING AN INVERSE BURNING FRONT IN AN OIL STRATUM SUSCEPTIBLE TO SPONTANEOUS COMBUSTION IN CONTACT WITH AIR, SAID STRATUM BEING PENETRATED BY AN INJECTION WELL AND A PRODUCTION WELL, WHICH COMPRISES THE STEPS OF: (A) INJECTING INTO SAID STRATUM THRU SAID INJECTION WELL A GAS OF INSUFFICIENT FREE O2 CONCENTRATION TO CAUSE SPONTANEOUS IGNITION IN SAID STRATUM AND PRODUCING FLUIDS FROM SAID PRODUCTION WELL DRIVEN INTO SAME BY SAID GAS; (B) CONTINUING STEP (A) WHILE GRADUALLY INCREASING THE O2 CONCENTRATION OVER A PERIOD OF AT LEAST SEVERAL WEEKS SO AS TO REACH THE O2 CONCENTRATION OF AIR AT THE END OF SAID PERIOD WITHOUT SPONTANEOUS IGNITION; (C) THEREAFTER, IGNITING SAID STRATUM AROUND SAID PRODUCTION WELL BY HEATING SAME TO IGNITION TEMPERATURE AND PASSING AIR FROM SAID INJECTION WELL TO THE HEATED AREA; AND (D) CONTINUING THE PASSING OF AIR FROM SAID INJECTION WELL TO THE IGNITED AREA TO ESTABLISH AN INVERSE BURNING COMBUSTION FRONT.