Downhole steam generator with improved preheating, combustion and protection features

An apparatus for generation of steam in a borehole for penetration into an earth formation, comprising:

• an oxidant supply means;
• a fuel supply means for supplying fuel;
• an ignitor means for igniting the fuel and oxidant mixture;
• a water supply means for providing water to be converted to steam by the heat of combustion;
• a combustor assembly having fuel inlet means, oxidant inlet means, a combustion chamber defined by a chamber wall for generating hot combustion gas, water inlet means to provide steam upon contact with the hot gas and steam outlet means;
• and
• a cylindrical outer housing sleeve, a cylindrical inner sleeve spaced between and concentric with respect to both said outer sleeve and the wall defining said combustion chamber, the space between said outer sleeve and said inner sleeve connected to said water supply means and defining a first annular water flow channel, the space between said inner sleeve and said combustion chamber wall connected to said water inlet means and defining a second annular water flow channel, and passage means interconnecting said first and second flow channels, whereby downward and upward flow of water through said channels cools said combustion chamber and preheats the water in a countercurrent manner.

An apparatus for generation of steam in a borehole comprising

• an oxidant supply means;
• a fuel supply means for supplying fuel;
• an igniter means for igniting the fuel and oxidant mixture;
• a water supply means for providing water to be converted to steam by the heat of combustion;
• a combustor assembly having fuel inlet means, oxidant inlet means, a combustion chamber for generating hot combustion gases, water inlet means to provide steam upon contact with the hot gas, steam outlet means, and door means operably connected to the steam outlet means;
• a control module comprising pressure and temperature transducer means for sensing parameters in said generator connected to said control module;
• and
• actuator means responsive to said control module to control the operation of said generator said actuator means being operably connected to said door means for adjusting the position of said door means responsive to the combustion chamber pressure.

An apparatus for generation of steam in a borehole comprising

• an oxidant supply means;
• a fuel supply means for supplying fuel;
• an igniter means for igniting the fuel and oxidant mixture;
• a water supply means for providing water to be converted to steam by the heat of combustion;
• a combustor assembly having fuel inlet means, oxidant inlet means, a combustion chamber for generating hot combustion gases, water inlet means to provide steam upon contact with the hot gas and steam outlet means;
• and
• door means operably connected to said steam outlet means and including a control module, transducer means in communication with said combustion chamber for sensing the pressure in said chamber, said transducer means being operably connected to the control module and including actuator means responsive to said control module to control the position of said door responsive to the combustion chamber pressure for the purpose of optimizing combustion in said chamber and for preventing a backflow of liquid from the borehole when the pressure in said chamber is too low.