Method and apparatus for repurposing well sites for geothermal energy production

Abstract

A method and system for capturing geothermal energy. Injection and production well pairs in a geothermal zone are connected with a power generation apparatus between the production well of one well pair and the injection well of an adjacent well pair in a subterranean closed loop daisy chain configuration. Fluid circulated through the loop and the power generation apparatus recover subterranean heat energy. Specification is also disclosed in respect of application of the technology to repurpose an unused or suspended oilfield.

I claim: 
     
         1 . A geothermal method, comprising:
 drilling a first generally U shaped bore hole into an earth formation and a second generally U shaped bore hole in spaced relation therefrom each in a geothermal zone within said formation;   providing a power generation apparatus;   connecting said apparatus to an output of said first U shaped bore hole and an inlet of said second U shaped bore hole;   circulating a fluid through each said bore hole; and   recovering heat from said fluid.   
     
     
         2 . The method as set forth in  claim 1 , wherein said earth formation is an oilfield. 
     
     
         3 . The method a set forth in  claim 1 , further including the step of recovering heat from said output of said first U shaped bore hole with said apparatus prior to introduction into said inlet of said second U shaped bore hole. 
     
     
         4 . The method as set forth in  claim 1 , further including the step of optionally bypassing said power generation apparatus. 
     
     
         5 . The method as set forth in  claim 1 , further including the step of connecting a series of first and second U shaped bore holes and power generation apparatus in a looped configuration. 
     
     
         6 . The method as set forth in  claim 5 , further including connecting discrete loops. 
     
     
         7 . The method as set forth in  claim 2 , wherein preexisting adjacent oil wells in said oilfield having an injection well and a production well are retrofitted for connection with said apparatus within a geothermal zone for heat recovery. 
     
     
         8 . The method as set forth in  claim 7 , further including the step of drilling additional U shaped wells for connection with said preexisting wells. 
     
     
         9 . An energy production method comprising:
 providing a suspended oilfield having injection and production well pairs;   connecting a power generation apparatus between the production well of one well pair and the injection well of an adjacent well pair in a subterranean loop; and   circulating a fluid through said loop to recover subterranean heat energy.   
     
     
         10 . The method as set forth in  claim 9 , further including connecting additional well pairs in a subterranean loop. 
     
     
         11 . The method as set forth in  claim 10 , further including connecting loops in a subterranean connection. 
     
     
         12 . The method as set forth in  claim 9 , further including bypassing said power generation apparatus. 
     
     
         13 . A system for energy production, comprising:
 injection and production well pairs in a geothermal zone within a formation;   a power generation apparatus connected between the production well of one well pair and the injection well of an adjacent well pair forming a closed loop; and   fluid for circulation through said loop and said power generation apparatus to recover subterranean heat energy.   
     
     
         14 . The system as set forth in  claim 13 , wherein said injection and production well pairs include a plurality of horizontal conduits. 
     
     
         15 . The system as set forth in  claim 14 , wherein said horizontal conduits are arranged in an annular form. 
     
     
         16 . The system as set forth in  claim 15 , wherein said conduits are in spaced relation. 
     
     
         17 . The system as set forth in  claim 13 , wherein said power generation apparatus comprises an organic Rankine cycle. 
     
     
         18 . The system as set forth in  claim 13 , wherein said power generation apparatus comprises a carbon carrier cycle. 
     
     
         19 . The system as set forth in  claim 13 , wherein said power generation apparatus comprises a Kalina cycle. 
     
     
         20 . The system as set forth in  claim 13 , wherein said formation is an oilfield.