Method and apparatus for ignition of downhole gas generator

A method of igniting a downhole gas generator, comprising the steps of:

• a) providing a mixing chamber;
• b) partially filling said chamber with liquid pyrophoric;
• c) heating said chamber;
• d) injecting gaseous fuel into said heated chamber at a location below said liquid pyrophoric such that said fuel bubbles through said liquid pyrophoric, wherein said gaseous fuel obtains an amount of vaporized pyrophoric therein to form said ignitable mixture;
• e) injecting said ignitable mixture into said gas generator along with an oxidant so as to produce combustion.

An apparatus for providing an ignitable mixture for use in the ignition of a downhole gas generator, comprising:

• a) a mixing chamber having top and bottom walls and a side wall extending between said top and bottom walls;
• b) a fuel inlet line communicating with said chamber near said bottom wall;
• c) a pyrophoric inlet line communicating with said chamber intermediate said top and bottom walls, sad pyrophoric inlet line having metering means for controlling the flow of said liquid pyrophoric therethrough;
• d) an outlet line communicating with said chamber near said top wall, said outlet line being adapted to be connected to an ignition location of said downhole generator;
• e) bubble means for causing gaseous fuel entering said chamber through said fuel inlet line to bubble through a reservoir of said liquid pyrophoric in said chamber, said bubble means being located inside said chamber between said pyrophoric inlet line and said fuel inlet line;
• f) heating means for heating said chamber to a temperature suitable for said gaseous fuel to obtain a vapor content of said liquid pyrophoric as said fuel bubbles through said pyrophoric, said heating means being located adjacent to said chamber.

A downhole gas generator system for use in enhanced oil recovery, comprising:

• a) a generator subsystem located downhole in a well borehole, said generator subsystem capable of producing gas for use in enhanced oil recovery, said generator subsystem comprising an oxidant inlet and a generator fuel inlet;
• b) an ignitor subsystem for producing an ignitable mixture, said ignitable mixture for use in igniting said generator subsystem downhole, said ignitor subsystem comprising:
• i) a mixing chamber having top and bottom walls and a side wall extending between said top and bottom walls;
• ii) a fuel inlet line communicating with said chamber near said bottom wall;
• iii) a pyrophoric inlet line communicating with said chamber intermediate said top and bottom walls, said pyrophoric inlet line having metering means for controlling the flow of said liquid pyrophoric therethrough;
• iv) an outlet line communicating with said chamber near said top wall, said outlet line being adapted to be connected to an ignition location of said downhole generator;
• v) bubble means for causing gaseous fuel entering said chamber through said fuel inlet line to bubble through a reservoir of said liquid pyrophoric in said chamber, said bubble means being located inside said chamber between said pyrophoric inlet line and said fuel inlet line;
• vi) heating means for heating said chamber to a temperature suitable for said gaseous fuel to obtain a vapor content of said liquid pyrophoric as said fuel bubbles through said pyrophoric, said heating means being located adjacent to said chamber;
• c) said outlet line communicating with said generator fuel inlet by way of metering means for metering the amount of ignitable mixture into said generator subsystem.

A method of providing an ignitable mixture for use in the ignition of a downhole gas generator, comprising the steps of:

• a) providing a mixing chamber;
• b) providing a supply of liquid pyrophoric in said chamber;
• c) injecting a gaseous fuel into said chamber in a turbulent manner, said fuel being subjected to a pressure drop before being injected into said chamber;
• d) impressing said pressure drop across said pyrophoric supply such that said pyrophoric is forced to flow into said chamber;
• e) mixing said turbulent gaseous fuel with said pyrophoric so as to cause said pyrophoric to break up into droplets and become entrained into said gaseous fuel, so as to form said ignitable mixture.

A method of igniting a downhole gas generator comprising the steps of:

• a) providing a mixing chamber;
• b) providing a supply of liquid pyrophoric in said chamber;
• c) injecting a gaseous fuel into said chamber in a turbulent manner, said fuel being subjected to a pressure drop before being injected into said chamber;
• d) impressing said pressure drop across said pyrophoric supply such that said pyrophoric is forced to flow into said chamber;
• e) mixing said turbulent gaseous fuel with said pyrophoric so as to cause said pyrophoric to break up into droplets and become entrained into said gaseous fuel, so as to form said ignitable mixture;
• f) injecting said ignitable mixture into said gas generator along with an oxidant so as to produce combustion.

An apparatus for producing an ignitable mixture for use in the ignition of a downhole gas generator, comprising:

• a) a mixing chamber having top and bottom walls and a side wall extending between said top and bottom walls, said chamber being cylindrical in extending between said top and bottom walls;
• b) a fuel inlet line communicating with said chamber near said bottom wall, said fuel inlet line configured to inject gaseous fuel into said chamber in a turbulent manner;
• c) an outlet line communicating with said chamber near said top wall, said outlet line being adapted to be connected to said downhole generator;
• d) a pyrophoric inlet line communicating with said chamber through an orifice such that liquid pyrophoric enters said chamber through said orifice;
• e) storage means for storing a supply of liquid pyrophoric, said storage means having top and bottom ends;
• f) said pyrophoric inlet line being connected to said storage means near said storage means bottom end;
• g) a pyrophoric supply line being connected with said storage means near said storage means top end;
• h) said fuel inlet line being connected to a supply of fuel, said fuel inlet line having pressure drop means located therein, said pressure drop means providing a drop in pressure of said fuel being injected into said chamber;
• i) said fuel supply being connected to said top end of said storage means, so as to impress said fuel pressure drop onto said liquid pyrophoric and draw said pyrophoric into said chamber through said orifice.

A downhole gas generator system for use in enhanced oil recovery, comprising:

• a) a generator subsystem adapted to be located downhole in a well borehole, said generator subsystem capable of producing gas for use in enhanced oil recovery, said generator subsystem comprising an oxidant inlet and a generator fuel inlet;
• b) an ignitor subsystem for producing an ignitable mixture, said ignitable mixture for use in igniting said generator subsystem downhole, said ignitor subsystem comprising:
• i) a mixing chamber having top and bottom walls and a side wall extending between said top and bottom walls, said chamber being cylindrical in extending between said top and bottom walls;
• ii) a fuel inlet line communicating with said chamber near said bottom wall, said fuel inlet line configured to inject gaseous fuel into said chamber in a turbulent manner;
• iii) an outlet line communicating with said chamber near said top wall, said outlet line being adapted to be connected to said downhole generator;
• iv) a pyrophoric inlet line communicating with said chamber through an orifice such that liquid pyrophoric enters said chamber through said orifice;
• v) storage means for storing a supply of liquid pyrophoric, said storage means having top and bottom ends;
• vi) said pyrophoric inlet line being connected to said storage means near said storage means bottom end;
• vii) a pyrophoric supply line being connected with said storage means near said storage means top end;
• viii) said fuel inlet line being connected to a supply of fuel, said fuel inlet line having pressure drop means located therein, said pressure drop means providing a drop in pressure of said fuel being injected into said chamber;
• ix) said fuel supply being connected to said top end of said storage means, so as to impress said fuel pressure drop onto said liquid pyrophoric and draw said pyrophoric into said chamber through said orifice;
• c) said outlet line communicating with said generator fuel inlet by way of metering means for metering the amount of ignitable mixture into said generator subsystem.