Method and system for enhanced oil recovery

Abstract

A system and method for gas injection enhanced oil recovery is disclosed herein. The method includes the step of burning solid fuel and an oxygen-bearing gas in a combustion chamber. The method also includes the step directing an output stream of the burning step through a fluid pathway extending from the combustion chamber and underground to push oil toward a well. The method includes the step maintaining the pressure in the combustion chamber above ambient during the burning step.

1 . A gas injection method for enhanced oil recovery comprising the steps of:
 burning solid fuel and an oxygen-bearing gas in a combustion chamber;   directing an output stream of said burning step through a fluid pathway extending from the combustion chamber and underground to push oil toward a well; and   maintaining the pressure in the combustion chamber above ambient during said burning step.   
     
     
         2 . The gas injection method of  claim 1  wherein said burning step is further defined as:
 burning solid fuel and substantially pure oxygen in the combustion chamber. 
 
     
     
         3 . The gas injection method of  claim 1  wherein said directing step is further defined as:
 directing all of the output stream of said burning step underground. 
 
     
     
         4 . The gas injection method of  claim 3  wherein said directing step is further defined as:
 directing all of the output stream of said burning step underground without compressing the output stream subsequent to said burning step. 
 
     
     
         5 . The gas injection method of  claim 1  wherein said directing step is further defined as:
 directing the output stream of said burning step underground with the pressure of the output stream being between substantially eighty percent and substantially ninety-nine percent of the pressure of the combustion chamber when the output stream moves below ground level. 
 
     
     
         6 . The gas injection method of  claim 1  wherein said directing step is further defined as:
 directing the output stream of said burning step underground while a temperature of the output stream is between substantially three percent and substantially ninety percent of a temperature of the combustion chamber when the output stream moves below ground level. 
 
     
     
         7 . The gas injection method of  claim 1  wherein said directing step is further defined as:
 directing the output stream of said burning step underground to push oil toward a well without compressing the output stream downstream of the combustion chamber. 
 
     
     
         8 . The gas injection method of  claim 1  wherein said maintaining step is further defined as:
 maintaining the pressure in the combustion chamber between 200-3000 pounds per square inch (p.s.i.) during said burning step. 
 
     
     
         9 . The gas injection method of  claim 1  further comprising the step of:
 extracting energy from the output stream of said burning step prior to the output stream moving underground during said directing step. 
 
     
     
         10 . The gas injection method of  claim 9  wherein said extracting step is further defined as:
 extracting thermal energy from the output stream of said burning step without causing a significant pressure drop in the output stream whereby additional compression of the output stream is required prior to the output stream moving underground. 
 
     
     
         11 . The gas injection method of  claim 9  further comprising the steps of:
 creating steam with the thermal energy extracted during said extracting step; and 
 passing the steam across a steam turbine to produce power. 
 
     
     
         12 . The gas injection method of  claim 11  wherein said maintaining step further comprises the steps of:
 compressing the oxygen-bearing gas to a first level of pressure with a compressor prior to said burning step; 
 at least substantially keeping the pressure of oxygen-bearing gas at the first level of pressure during said burning step; and 
 coupling the compressor and the steam turbine such that the steam turbine powers the compressor. 
 
     
     
         13 . The gas injection method of  claim 11  further comprising the steps of:
 separating oxygen from air with an oxygen separator on site with the combustion chamber; and 
 delivering the separated oxygen to the combustion chamber. 
 
     
     
         14 . The gas injection method of  claim 11  further comprising the steps of:
 pulverizing the solid fuel with a pulverizer; 
 delivering the pulverized solid fuel to the combustion chamber with a conveyor; and 
 powering the pulverizer and the conveyor with at least a portion of the power produced during said passing step. 
 
     
     
         15 . The gas injection method of  claim 11  further comprising the steps of:
 removing ash from the output stream with ash removal equipment; and 
 powering the ash removal equipment with at least a portion of the power produced during said passing step. 
 
     
     
         16 . The gas injection method of  claim 11  further comprising the steps of:
 compressing the oxygen-bearing gas to a first level of pressure prior to said burning step with a compressor; 
 providing oxygen to the combustion chamber with an oxygen separator on site with the combustion chamber; 
 delivering the pulverized solid fuel to the combustion chamber with a solid fuel handler; and 
 powering the compressor, the oxygen separator, and the solid fuel handler with at least portions of the power produced during said passing step, wherein the energy extracted during said extracting step to produce power delivered during said powering step is limited such that the output stream does not require compression downstream of the combustion chamber. 
 
     
     
         17 . The gas injection method of  claim 9  wherein said extracting step is further defined as:
 extracting energy from the output stream of said burning step prior to the output stream moving underground during said directing step such that an amount of energy extracted is in excess of that needed to carry out said maintaining and directing steps. 
 
     
     
         18 . The gas injection method of  claim 9  wherein said extracting step is further defined as:
 extracting energy from the output stream of said burning step prior to the output stream moving underground during said directing step such that an amount of energy extracted is in excess of that needed to carry out said maintaining and directing steps and wherein the amount of energy extracted is limited such that the output stream does not require compression downstream of the combustion chamber before moving underground. 
 
     
     
         19 . A system for gas injection method of enhanced oil recovery comprising:
 a combustion chamber operable to contain solid fuel and an oxygen-bearing gas while burning at a pressure maintained above ambient; and   a fluid pathway extending downstream of the combustion chamber and underground for directing an output stream of the combustion chamber underground to a push oil toward a well.   
     
     
         20 . The system of  claim 19  further comprising:
 a heat exchanger disposed along the fluid pathway and operable to extract heat from the output stream; 
 a steam turbine; 
 a fluid circuit including said heat exchanger and said steam turbine wherein a heat transfer fluid passing through said fluid circuit absorbs heat in said heat exchanger to become steam and then passes across said steam turbine; 
 a compressor operable to pressurize the oxygen-bearing gas prior to the oxygen-bearing gas passing into said combustion chamber, wherein said compressor is powered by said steam turbine; and 
 an oxygen separator powered by said steam turbine and operable to generate substantially pure oxygen to said compressor.