| abstract |
A hot fluid, e.g., steam, combustion gas, CO2, natural gas, etc., is injected preferably into the gas cap above an oil interval or formation, followed by sufficient water to partially seal the treated formation against fingering and channeling of air later injected, then injecting air to cause spontaneous ignition and in situ combustion of gas and/or residual oil in the gas cap creating heat and pressure whereby viscosity of oil is reduced and oil is moved in improved manner toward producing wells. |