Superheated steam water treatment process

Abstract

Methods and apparatus produce steam and, more particularly, utilize untreated feedwater as a source for steam used in steam assisted gravity drainage. Superheated steam, produced from treated feedwater in a boiler, is used to vaporize untreated feedwater that would otherwise foul a boiler. Contaminants in the untreated water can them be removed as solids or concentrated brine. The vaporization process occurs in stages to allow for the use of a higher fraction of untreated water.

What is claimed is: 
     
         1 . A method of producing steam for heavy oil recovery, comprising:
 a) introducing an initial superheated steam into a contactor vessel;   b) introducing a feedwater stream into said contactor vessel;   c) mixing said initial superheated steam and said feedwater to produce a less heated steam and contaminants in said contactor vessel;   d) separating said less heated steam from said contaminants;   e) again superheating said less heated steam in a furnace to create a superheated steam and repeating steps a-e in sequential contactor vessels of decreasing pressure;   f) flowing a final less heated steam from a final contactor vessel; and   g) injecting said final less heated steam into an injection well for the mobilization of heavy oil.   
     
     
         2 . The method of  claim 1 , wherein said contaminants are solid minerals. 
     
     
         3 . The method of  claim 1 , wherein separation of the less heated steam from said contaminants is preformed using a solids separation device. 
     
     
         4 . The method of  claim 1 , wherein separation of the less heated steam from said contaminants is preformed using a cyclone or filter. 
     
     
         5 . The method of  claim 1 , wherein said contaminants are in a liquid phase and separated by a gas-liquid separator. 
     
     
         6 . The method of  claim 1 , where said contaminants are separated as concentrated brine that undergoes further vaporization in a single mixer and solids are thereafter removed via a separator. 
     
     
         7 . The method of  claim 1 , where said contaminants are separated as concentrated brine that undergoes further vaporization in a single mixer and solids are thereafter removed via a cyclone or filter. 
     
     
         8 . The method of  claim 1 , further comprising adding additional superheated steam to the less heated steam, between steps d and e, after being separated from the contaminants and before superheating again in the furnace. 
     
     
         9 . The method of  claim 1 , wherein said initial superheated steam is heated to 482-538° C. using a power plant boiler or a fired steam superheater. 
     
     
         10 . The method of  claim 1 , wherein said initial superheated steam is heated to 482-538° C. using a power plant boiler. 
     
     
         11 . The method of  claim 1 , wherein the initial ratio of said superheated steam to said feedwater is 2.5-4.5. 
     
     
         12 . The method of  claim 1 , wherein the initial ratio of said superheated steam to said feedwater is 3.3. 
     
     
         13 . The method of  claim 1 , wherein said superheated steam is 482-538° C. 
     
     
         14 . A steam production system for heavy oil recovery, comprising:
 a) a boiler;   b) a furnace;   c) n mixers and n separators for separating steam from solid and/or liquids, wherein each of said n mixer is fluidly connected to an n separator which is fluidly connected to said furnace, and wherein the furnace is fluidly connected to each of said n mixer, and wherein n is at least 3;   d) n inlet lines connected to each of said n mixers for feeding untreated water to each mixer;   e) said boiler fluidly connected to a first one of the mixers; and   f) a last one of the mixers fluidly connected to a heavy oil injection well.   
     
     
         15 . The system of  claim 14 , wherein the mixers contact the untreated water and superheated steam to produce a less heated steam and contaminants removed by the separators in a plurality of stages and the furnace superheats said less heated steam received from said mixers and separators and thereby generates additional superheated steam directed to a next stage of the mixers and separators. 
     
     
         16 . The system of  claim 14 , further comprising a vessel for vaporizing said liquids removed from the steam by the separators and a solids removal device for separating solid-waste from resulting additional steam generated in the vessel. 
     
     
         17 . The system of  claim 14 , wherein the separators are gas-liquid separators for removing brine from the steam generated in the mixers. 
     
     
         18 . The system of  claim 14 , wherein the separators are solids separation devices for removing solid minerals from the steam generated in the mixers. 
     
     
         19 . The system of  claim 14 , further comprising a pipe to combine an additional amount of superheated steam with the steam at an outlet from said separators but before said furnace. 
     
     
         20 . A method of steam assisted gravity drainage (SAGD), comprising:
 injecting steam into a horizontal injection well and recovering produced hydrocarbons from a lower horizontal production well; and   preparing the steam for said injection wells by i) superheating steam, ii) mixing said superheated steam with untreated water to produce steam and solids or concentrated brine or both, iii) separating said solids or concentrated brine from said steam in step ii), iv) re-superheating said steam in a furnace, and v) repeating steps ii-iv) at least two more times.