Method of thermal stimulation of oil fields

Claim 1

AN IN SITU COMBUSTION PROCESS FOR RECOVERING OIL FROM AN UNDERGROUND OIL-BEARING FORMATION PENETRATED BY AT LEAST ONE WELL BORE CHARACTERIZED BY THE BROAD DISTRIBUTION OF HEAT IN THE INTERIOR REGIONS OF THE RESERVOIR WHICH COMPRISES THE STEPS, INJECTING A SLUG OF A LOW VISCOSITY, OIL-MISCIBLE LIQUID INTO THE FORMATION FROM AN INPUT WELL, SAID OIL-MISCIBLE LIQUID BEING NOT SELF-IGNITABLE IN THE PRESENCE OF OXYGEN, INJECTING AN OXIDIZING GAS INTO THE WELL AT A SUFFICIENTLY HIGH PRESSURE THAT IT WILL DIRVE THE MISCIBLE LIQUID AND THE OIL AHEAD OF IT TO FORM A GREAT MULTIPLE OF FINGERS PROJECTING DEEPLY INTO THE FORMATION WITH THE MISCIBLE LIQUID FORMING A SEPARATING LAYER BETWEEN THE OXIDIZING GAS AND THE OIL, INJECTING ADDITIONAL OXIDIZING GAS UNDER HIGH PRESSURE TO CAUSE THE MISCIBLE LIQUID LAYER TO MOVE FURTHER FROM THE WELL, WHEREBY SAID LAYER IS THINNED OUT AND DISSIPATED AND WHEREBY THE OIL IN THE FORMATION CONTACTS SAID GAS TO CAUSE THE OIL TO BE IGNITED ALONG THE PERIPHHERIES OF THE FINGERS, MAINTAINING THE INJECTION OF OXIDIZING GAS AT A HIGH RATE TO CAUSE THE CONCURRENT COMBUSTION OF THE IGNITED OIL OVER A WIDE RADIAL FROM TO HEAT A SUBSTANTIAL VOLUME OF THE RESERVOIR, AND PRODUCING THE MOBILIZED OIL FROM SAID FORMATION AT LEAST PARTIALLY THROUGH SAID FINGERS.