Porous media gas burner

Abstract

A porous media gas burner is adapted to operate in a pressurized environment. The burner may have three zones: a mixing zone, an ignition zone and a reaction zone. The burner may be used as a downhole burner in a formation heat treatment method for oil and gas wells.

1 . A downhole formation heating system for a wellbore including a well casing, the system comprising: 
 (a) a gas burner comprising a cylindrical housing defining an intake opening and a flue opening, the housing comprising means for receiving a supply of fuel and air; a mixing zone where the fuel and air are mixed; an ignition zone comprising an igniter and a reaction zone, each zone comprising a packed bed of porous media;    (b) an igniter for igniting the fuel and air within the gas burner;    (c) fuel and air supply tubing for delivering fuel and air to the burner; and    (d) means for delivering pressurized air or an inert gas in an annular space between the well casing and the fuel and air supply tubing.    
   
   
       2 . The system of  claim 1  wherein the porous media comprises ceramic beads.  
   
   
       3 . The system of  claim 2  wherein the ceramic beads comprises alumina beads.  
   
   
       4 . The system of  claim 1  wherein the mixing zone and reaction zone comprise a pore size less than a minimum quenching distance under standard conditions of a fuel gas and the ignition zone comprises a pore size greater than the minimum quenching distance under standard conditions of the fuel gas.  
   
   
       5 . A method of heat treating a formation comprising the steps of: 
 (a) inserting a gas burner comprising a cylindrical housing defining an intake opening and a flue opening, the housing comprising means for receiving a supply of fuel and air; a mixing zone where the fuel and air are mixed; an ignition zone comprising an igniter and a reaction zone, each zone comprising a packed bed of porous media, into a wellbore;    (b) injecting a fuel gas and air into the gas burner to create a combustible mixture and igniting the mixture to create a combustion front; and    (c) causing the combustion front to travel out the gas burner and into the formation.    
   
   
       6 . The method of  claim 5  wherein one zone of the gas burner has a pore size smaller than a minimum quenching distance for an operating condition of pressure and fuel.  
   
   
       7 . A gas burner comprising a tubular housing adapted to operate in a pressurized environment, the housing defining an intake opening and a flue opening and comprising means for receiving a supply of fuel and air; a mixing zone where the fuel and air are mixed comprising a packed bed of porous media; an ignition zone comprising a packed bed of porous media, and a reaction zone comprising a packed bed of porous media; wherein the pore size of the mixing zone and the reaction zone is smaller than a minimum quenching distance of a fuel gas under standard conditions while the pore size of the ignition zone is larger than the minimum quenching distance.  
   
   
       8 . The burner of  claim 5  wherein the flue opening combines with a pressure regulator for controlling the pressure within the gas burner above atmospheric pressure.