Apparatus and method for downhole steam generation and enhanced oil recovery

Abstract

A burner is arranged for access to a cavity in a target zone of a hydrocarbon reservoir. The burner is operated into the cavity to create and sustain hot combustion gases at a steady state for flowing into and permeating through the target zone. Water is injected into the target zone and permeates laterally therein. The hot combustion gases and the water in the target zone interact to form a steam drive front in the hydrocarbon reservoir.

The embodiments of the invention for which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A system for enhanced oil recovery from a hydrocarbon reservoir accessed by a cased and completed wellbore having a wellhead, the system comprising:
 a downhole burner for creating hot combustion gases within a target zone in the hydrocarbon reservoir; and   at least two tubing strings positioned within the wellbore for forming three discrete fluid passageways for conducting at least fuel and oxidant to the downhole burner,   wherein one of the three discrete fluid passageways is a sealed fluid passageway for isolating the other two of the three discrete fluid passageways from one another.   
     
     
         2 . The system of  claim 1 , wherein the sealed fluid passageway is pressurized to a pressure higher than a pressure in both the fuel passageway and the oxidant passageway. 
     
     
         3 . The system of  claim 1 , wherein the sealed fluid passageway is pressurized with an inert gas. 
     
     
         4 . The system of  claim 3 , wherein the inert gas is nitrogen gas. 
     
     
         5 . The system of  claim 1 , wherein the at least two tubing strings are concentric tubing strings. 
     
     
         6 . The system of  claim 5 , wherein the three discrete fluid passageways further comprise an outer fluid passageway, the sealed fluid passageway and an inner fluid passageway, and wherein the at least fuel is conducted through the outer passageway, the oxidant is conducted through the inner fluid passageway and the sealed fluid passageway is pressurized with nitrogen gas. 
     
     
         7 . The system of  claim 5 , wherein the three discrete fluid passageways further comprises an outer fluid passageway, the sealed fluid passageway and an inner fluid passageway, and wherein the oxidant is conducted through the outer passageway, the at least fuel is conducted through the inner fluid passageway and the sealed fluid passageway is pressurized with nitrogen gas. 
     
     
         8 . The system of  claim 1 , further comprising a sensor for monitoring for changes in pressure in the sealed fluid passageway. 
     
     
         9 . A process of creating a drive front in a hydrocarbon reservoir for enhanced oil recovery comprising the steps of:
 positioning a burner assembly within a target zone in the hydrocarbon reservoir;   providing a fuel passageway for delivering fuel to the burner assembly;   providing an oxidant passageway for delivering oxidant to the burner assembly; and   isolating the fuel passageway from the oxidant passageway.   
     
     
         10 . The process of  claim 9 , wherein isolating the fuel passageway from the oxidant passageway further comprises providing a sealed fluid passageway. 
     
     
         11 . The process of  claim 10 , further comprising pressurizing the sealed fluid passageway to a pressure higher than the pressure in both the fuel passageway and the oxidant passageway. 
     
     
         12 . The process of  claim 11 , wherein pressurizing the sealed fluid passageway further comprises pressurizing the sealed fluid passageway with an inert gas. 
     
     
         13 . The process of  claim 12 , wherein the inert gas further comprises nitrogen gas. 
     
     
         14 . The process of  claim 10 , further comprising monitoring the sealed fluid passageway for changes in pressure. 
     
     
         15 . A process of creating a drive front in a hydrocarbon reservoir for enhanced oil recovery comprising the steps of:
 conducting at least fuel and oxidant to a downhole burner assembly positioned within the hydrocarbon reservoir;   isolating the at least fuel from the oxidant with an inert gas; and   combusting the at least fuel and oxidant to create the drive front.   
     
     
         16 . The process of  claim 15  wherein isolating the at least fuel from the oxidant with an inert gas further comprises pressurizing the inert gas to a pressure greater than a pressure of the at least fuel and the oxidant. 
     
     
         17 . The process of  claim 15 , wherein the inert gas is nitrogen gas. 
     
     
         18 . The process of  claim 15 , wherein conducting at least fuel and oxidant further comprising monitoring for changes in pressure.