Patent ID: 7493953

Claim:
A process for extracting liquid hydrocarbons from an underground reservoir, comprising the steps of: (a) providing at least one injection well for injecting an oxidizing gas into an upper part of an underground reservoir; (b) said at least one injection well further adapted for injecting steam, a non-oxidizing gas, or water which is subsequently heated to steam, into a lower part of an underground reservoir; (c) providing at least one production well having a substantially horizontal leg and a substantially vertical production well connected thereto, wherein the substantially horizontal leg extends toward the injection well, the horizontal leg having a heel portion in the vicinity of its connection to the vertical production well and a toe portion at the opposite end of the horizontal leg, wherein the toe portion is closer to the injection well than the heel portion; (d) injecting an oxidizing gas through the injection well for in situ combustion, so that combustion gases are produced, wherein the combustion gases progressively advance laterally as a front, substantially perpendicular to the horizontal leg, in the direction from the toe portion to the heel portion of the horizontal leg, and fluids drain into the horizontal leg; (e) injecting a medium, wherein said medium is selected from the group of mediums comprising steam, water or a non-oxidizing gas, into said injection well; and (f) recovering hydrocarbons in the horizontal leg of the production well from said production well.