Method and apparatus for disposal of well flare gas in oil and gas drilling and recovery operations

Abstract

A wellhead gas recovery system and method for the generation of power from wellhead gas is provided. A gas conduit is used to direct wellhead gas from a wellhead casing or wellhead bore to a stirling engine where the wellhead gas is used as the fuel source for the stirling engine. The wellhead gas is ignited and the burning wellhead gas is used as the heat source for the stirling engine. The thermal energy from the burning wellhead gas is converted transferred into motion by the stirling engine and the output of the stirling engine can be used to drive devices at the wellsite, generate electricity or other use.

1 . A wellhead gas recovery system for the generation of power, the system comprising:
 a stirling engine, comprising a combustor; and   a gas conduit operative to route wellhead gas from a wellhead to the stirling engine,   wherein the wellhead gas routed to the stirling engine is ignited by the combustor and the ignited wellhead gas acts as a heat source to drive the stirling engine.   
   
   
       2 . The system of  claim 1  wherein the stirling engine comprises at least one combustion chamber and wellhead gas is directed to the at least one combustion chamber by the gas conduit and the wellhead gas is ignited in the at least one combustion chamber by the combustor. 
   
   
       3 . The system of  claim 2  wherein the at least one combustion chamber is operably removable whereby the at least one combustion clamber can be removed and replaced when the at least one combustion chamber becomes corroded from the wellhead gas. 
   
   
       4 . The system of  claim 2  wherein the at least one combustion chamber comprises a corrosion resistant material. 
   
   
       5 . The system of  claim 1  wherein power generated by the stirling engine is used to drive an output shaft. 
   
   
       6 . The system of  claim 1  wherein power generated by the stirling engine is used to drive an electrical generator to output electrical energy. 
   
   
       7 . The system of  claim 6  wherein the electrical generator is operatively connected to an electrical power grid and wherein electrical energy produced by the electrical generator is supplied to the electrical power grid. 
   
   
       8 . The system of  claim 1  further comprising:
 a compressor located inline on the gas conduit and operative to compress wellhead gas passing through the gas conduit to a predetermined pressure;   a pressure vessel located inline on the gas conduit and downstream from the compressor, the pressure vessel operative to store wellhead gas pressurized by the compressor; and   a pressure regulator valve, located inline on the gas conduit and downstream from the pressure vessel, the pressure regulator valve operative to allow a regulated flow of pressurized wellhead gas at a predetermined pressure from the pressure vessel to the stirling engine.   
   
   
       9 . The system of  claim 1  comprising:
 a first stirling engine connectable to the gas conduit by a first pressure regulator valve; and   a second stirling engine connectable to the gas conduit,   wherein wellhead gas is supplied to both the first stirling engine and the second sterling engine and wherein wellhead gas is ignited in the first stirling engine and second stirling engine to drive the first stirling engine and second stirling engine, respectively.   
   
   
       10 . A method of using a stirling engine to recover energy from wellhead gas, the method comprising:
 routing wellhead gas to a stirling engine;   igniting the wellhead gas;   using the ignited wellhead gas as a heat source to drive the stirling engine.   
   
   
       11 . The method of  claim 10  wherein the wellhead gas is directed to at least one combustion chamber of the stirling engine and ignited in the at least one combustion chamber. 
   
   
       12 . The method of  claim 11  comprising replacing the at least one combustion chamber when the at least one combustion chamber has become corroded. 
   
   
       13 . The method of  claim 11  wherein the at least one combustion chamber comprises a corrosion resistant material. 
   
   
       14 . The method of  claim 10  comprising using power generated by the stirling engine to drive an output shaft. 
   
   
       15 . The method of  claim 10  comprising using power generated by the stirling engine to generate electricity. 
   
   
       16 . The method of  claim 15  wherein the electricity generated by the stirling engine is supplied to an electrical grid.