Patent attributes
A modified method for in situ recovery of hydrocarbon from an underground hydrocarbon-containing formation. An “L” shaped production well, having a vertical section, and a lower horizontal leg positioned low in the formation, is provided. The horizontal leg connects to the vertical section at a heel portion, and has a toe portion at an opposite end thereof. Oxidizing gas is injected into the formation in or proximate the vertical section. A combustion front sweeps outwardly from the vertical section and laterally within the formation above the horizontal leg, from the heel to the toe, causing hydrocarbons in the formation above the horizontal leg to drain downwardly into the horizontal leg, which are then delivered to surface via production tubing. A non-oxidizing gas is injected into at least the heel portion and preferably additional portions of the horizontal leg via injection tubing contained within the vertical section of the production well.
