Supercritical boiler for oil recovery

Abstract

Method and systems relate to generating steam by transitioning water from supercritical conditions and injecting the steam that results into a formation to facilitate recovery of oil. Pressurizing and heating the water forms a supercritical fluid that may solvate impurities in the water and/or oxidize the impurities. Retaining the impurities in solution and/or oxidation of the impurities limits fouling problems associated with generating the steam from water recycled in thermal processes, such as steam assisted gravity drainage (SAGD), for recovering the oil.

1 . A method of generating steam for oil production, comprising:
 pressurizing and heating water to form a supercritical fluid;   converting at least some of the supercritical fluid to the steam; and   injecting the steam into a formation to facilitate the oil production.   
     
     
         2 . The method according to  claim 1 , wherein impurities in the water react within the supercritical fluid to form products that do not form solids upon generation of the steam. 
     
     
         3 . The method according to  claim 1 , wherein dissolved organic compounds in the water react within the supercritical fluid to form carbon dioxide that is injected with the steam. 
     
     
         4 . The method according to  claim 1 , wherein dissolved organic compounds in the water react within the supercritical fluid resulting in at least a 50 percent reduction in total organic carbon content by mass in the water. 
     
     
         5 . The method according to  claim 1 , wherein the supercritical fluid is converted to steam that is superheated. 
     
     
         6 . The method according to  claim 1 , wherein impurities in the water remain solvated within the supercritical fluid during the heating. 
     
     
         7 . The method according to  claim 1 , wherein the supercritical fluid is converted to the steam at conditions below a saturated state to generate the steam that is wet. 
     
     
         8 . The method according to  claim 1 , wherein impurities in the water remain solvated within the supercritical fluid during the heating and the supercritical fluid is then converted to the steam at conditions below a saturated state to generate the steam that is wet with the impurities remaining in a liquid phase. 
     
     
         9 . The method according to  claim 1 , wherein the converting at least some of the supercritical fluid to steam includes reducing pressure of the supercritical fluid to between 9 and 10 megapascals. 
     
     
         10 . The method according to  claim 1 , wherein the converting at least some of the supercritical fluid to steam includes reducing pressure of the supercritical fluid from above 22 megapascals to between 3 and 10 megapascals. 
     
     
         11 . The method according to  claim 1 , wherein the injecting of the steam is into a horizontal well disposed in fluid communication with a horizontal producer well for steam assisted gravity drainage production. 
     
     
         12 . The method according to  claim 1 , wherein the water is pumped to a pressure above  22  megapascals to provide pressurized water that is then heated to above 375° C. to provide the supercritical fluid. 
     
     
         13 . A steam generating system for oil production, comprising:
 a pump having a pressurized fluid outlet through which the pump is configured to provide water at above 22 megapascal;   a furnace coupled to receive the water from the pressurized outlet of the pump and having a heated fluid outlet through which a supercritical fluid is provided by the furnace configured to increase temperature of the water to above 375° C.;   a letdown device coupled to the heated fluid outlet of the furnace to receive the supercritical fluid and configured to produce steam from pressure reduction of the supercritical fluid; and   an injection well coupled with an outlet of the letdown device for conveying the steam into a formation to facilitate the oil production.   
     
     
         14 . The system according to  claim 13 , wherein the letdown device further includes a heat exchanger for cooling the supercritical fluid. 
     
     
         15 . The system according to  claim 13 , wherein the letdown device includes a flow restrictor for the pressure reduction of the supercritical fluid. 
     
     
         16 . The system according to  claim 13 , wherein the injection well is horizontal and disposed in fluid communication with a horizontal producer well for steam assisted gravity drainage production. 
     
     
         17 . The system according to  claim 13 , wherein the letdown device is configured to produce the steam that is superheated. 
     
     
         18 . A method of generating steam for oil production, comprising:
 reducing level of fouling precursors in water by oxidation of the fouling precursors in the water at a pressure and temperature above a critical point thereof;   transitioning the water from supercritical conditions above the critical point to below the critical point for generation of the steam; and   injecting the steam into a formation to facilitate the oil production.   
     
     
         19 . The method according to  claim 18 , wherein the fouling precursors include dissolved organics converted to carbon dioxide for injecting with the steam. 
     
     
         20 . The method according to  claim 18 , wherein the reducing the level of fouling precursors includes at least a 50 percent reduction in total organic carbon content by mass in the water.