Patent ID: 6016867
Filing Date: 2000-01-25
Classification: E21B

Abstract:
A process for continuously converting, upgrading, and recovering heavy hydrocarbons from a subsurface formation, said process being free of in situ combustion operations (i.e., free from the injection of hot oxidizing fluids into said subsurface formation for the purpose of igniting a portion of said heavy hydrocarbons) and being free of injection of catalysts into the subsurface formation, and said process comprising the steps of:a. inserting a downhole combustion unit into at least one injection borehole which communicates with at least one production borehole, said downhole combustion unit being placed at a position within said injection borehole in proximity to said subsurface formation;b. flowing from the surface to said downhole combustion unit within said injection borehole a set of fluids--comprised of steam, reducing gases, and oxidizing gases--and burning at least a portion of said reducing gases with said oxidizing gases in said downhole combustion unit;c. injecting a gas mixture--comprised of combustion products from the burning of said reducing gases with said oxidizing gases, residual reducing gases, and steam--from said downhole combustion unit into said subsurface formation;d. recovering from said production borehole, production fluids comprised of said heavy hydrocarbons, which may be converted to lighter hydrocarbons, as well as residual reducing gases, and other components;e. continuing steps b, c, and d until the recovery rate of said heavy hydrocarbons within said subsurface formation in the region between said injection borehole and said production borehole is reduced below a level of practical operation.