Steam quality boosting

Abstract

Disclosed are methods for providing steam suitable for injecting into a subterranean oil well, wherein fuel is combusted within a conduit that contains the steam to provide direct heat transfer of the heat of combustion to the steam.

What is claimed is: 
     
         1 . A method of providing steam suitable for injection into a subterranean oil well, comprising
 combusting fuel with gaseous oxidant and subjecting a stream that comprises steam flowing from a source of said steam to a subterranean oil well to direct heat transfer to said stream of heat produced by said combustion, thereby increasing the steam quality of said stream to a value that is above  80 % and that is higher than the steam quality of the stream produced by said source.   
     
     
         2 . A method according to  claim 1  wherein the stream which is subjected to said direct heat transfer contains liquid water, and the method further comprises separating liquid water from the stream which has been subjected to said direct heat transfer, thereby providing a product stream comprising steam. 
     
     
         3 . A method according to  claim 1  wherein said gaseous oxidant is air. 
     
     
         4 . A method according to  claim 1  wherein said gaseous oxidant comprises at least 25 vol. % oxygen. 
     
     
         5 . A method according to  claim 1  wherein said gaseous oxidant comprises at least 90 vol. % oxygen. 
     
     
         6 . A method according to  claim 2  further comprising further heating the product stream. 
     
     
         7 . A method according to  claim 2  further comprising further heating the product stream by direct heat transfer or indirect heat transfer with heat of combustion produced by further combustion of fuel and gaseous oxidant. 
     
     
         8 . A method according to  claim 7  wherein said gaseous oxidant combusted in said further combustion is air. 
     
     
         9 . A method according to  claim 7  wherein said gaseous oxidant combusted in said further combustion comprises at least 25 vol. % oxygen. 
     
     
         10 . A method according to  claim 7  wherein said gaseous oxidant combusted in said further combustion comprises at least 90 vol. % oxygen. 
     
     
         11 . A method according to  claim 6  wherein said stream of steam flowing from said source to said oil well loses heat to the environment, and wherein said further heating of said product stream imparts enough energy to said product stream such that the temperature of said product stream at said oil well is at least equal to the temperature of the stream produced by said source or the steam quality of said product stream at said oil well is at least equal to the steam quality of the stream produced by said source. 
     
     
         12 . A method according to  claim 11  wherein said further heating of said product stream imparts enough energy to said product stream that the temperature of said product stream at said oil well is higher than the temperature of the stream produced by said source or the steam quality of said product stream at said oil well is higher than the steam quality of the stream produced by said source. 
     
     
         13 . A method according to  claim 6  wherein said stream of steam flowing from said source to said oil well loses heat to the environment, and wherein said further heating of said product stream imparts enough energy to said product stream such that the steam quality of said product stream at said oil well is at least 99%. 
     
     
         14 . A method according to  claim 6  wherein said stream of steam flowing from said source to said oil well loses heat to the environment, and wherein said further heating of said product stream imparts enough energy to said product stream such that said product stream at said oil well is saturated steam. 
     
     
         15 . A method according to  claim 6  wherein said stream of steam flowing from said source to said oil well loses heat to the environment, and wherein said further heating of said product stream imparts enough energy to said product stream such that said product stream at said oil well is superheated. 
     
     
         16 . A method according to  claim 1  wherein said direct heat transfer causes the steam quality of the product stream at said oil well to be at least 98%. 
     
     
         17 . A method of providing steam suitable for injection into a subterranean oil well, comprising
 feeding fuel and gaseous oxidant into a stream that comprises steam flowing in a conduit from a source of said steam to a subterranean oil well, wherein said fuel and said oxidant are fed into said stream from one or more outlets located in said stream within said conduit, and   combusting said fuel with said oxidant at one or more of said outlets in direct contact with said steam, and heating said steam by direct contact of said steam with hot combustion products produced by said combustion.   
     
     
         18 . A method according to  claim 17  wherein said stream of steam into which said fuel and oxidant are fed contains liquid water, and wherein said heating of said steam evaporates at least a portion of said liquid water. 
     
     
         19 . A method according to  claim 17  wherein said stream of steam flowing in said conduit loses heat to the environment outside said conduit, and wherein said direct contact of said steam with said hot combustion products imparts enough energy to said steam such that the temperature or quality of said steam at said oil well is at least equal to its temperature or quality at the source of said steam. 
     
     
         20 . A method according to  claim 17  wherein said stream of steam from said source contains liquid water, the method further comprising physically reducing the amount of liquid water in said stream that contacts the base of the flame that is formed by combusting said fuel and said oxidant. 
     
     
         21 . A method according to  claim 20  wherein said reducing the amount of liquid water comprises passing said stream toward a deflector disposed between the path of said stream and said base of said flame, the deflector only partially surrounding said base, wherein liquid water contacts said deflector instead of contacting said base of said flame. 
     
     
         22 . A method according to  claim 20  wherein said reducing the amount of liquid water comprises, before said stream contacts said base of said flame, flowing said stream through a path that causes liquid water in said stream to move toward an inner surface of said conduit and in a path that differs from the path of said stream. 
     
     
         23 . A method of providing steam suitable for injection into a subterranean oil well, comprising
 feeding fuel and gaseous oxidant into a stream that comprises steam flowing in a conduit from a source of said steam in a subterranean oil well, wherein said fuel and said oxidant are fed into said stream from one or more outlets located in said stream within said conduit, and   combusting said fuel with said oxidant at one or more of said outlets in direct contact with said steam, and heating said steam by direct contact of said steam with hot combustion products produced by said combustion.