Patent ID: 7493952
Filing Date: 2009-02-24
Classification: E21B

Abstract:
1. 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 the underground reservoir; (b) 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; (c) injecting an oxidizing gas through the injection well to conduct in situ combustion, so that combustion gases are produced so as to cause the combustion gases to 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; (d) providing a tubing inside the production well within said vertical leg and at least a portion of said horizontal leg for the purpose of injecting steam, water or non-oxidizing gas into said horizontal leg portion of said production well proximate a combustion front formed at a horizontal distance along said horizontal leg of said production well; (e) injecting a medium selected from the group of mediums comprising steam, water, or non-oxidizing gas, into said tubing so that said medium is conveyed proximate said toe portion of said horizontal leg portion via said tubing; and (f) recovering hydrocarbons in the horizontal leg of the production well from said production well.