Geothermal loop energy production systems

Abstract

Tiered or stacked geothermal loop energy systems may include closed-loop pipe systems disposed within a heat producing geologic formation. The pipe systems are emplaced in wellbores drilled so as to efficiently and effectively take advantage of localized formation properties.

What is claimed: 
     
         1 . A method of efficiently harvesting geothermal energy, comprising:
 drilling a first wellbore into a subsurface geologic formation;   collecting data from the subsurface geologic formation while drilling the first wellbore;   analyzing the collected data to identify a target zone;   drilling a second wellbore to the identified target zone; and   emplacing a closed-loop pipe system within the second wellbore to harvest energy from the target zone.   
     
     
         2 . The method of  claim 1 , wherein the collecting data comprises one or more of:
 recording a temperature of the subsurface geologic formation;   recording a pressure of the subsurface geologic formation;   recording microseismic data during the drilling;   recording a position of a drill bit in the wellbore during the drilling;   measuring a property of the subsurface formation using a measurement tool.   
     
     
         3 . The method of  claim 1 , wherein the analyzing the collected data comprises one or more of:
 determining a location of a boundary between a convection zone and a caprock zone;   determining a location of a fault in a caprock zone;   determining a location of a fault in a convection zone (advection zone);   determining a zone comprising rock with permeability suitable for movement of geothermal brine.   
     
     
         4 . The method of  claim 3 , wherein determining a zone comprising rock with permeability suitable for movement of geothermal brine comprises identifying a zone having a permeability of at least 50 Darcy. 
     
     
         5 . The method of  claim 3 , wherein determining a zone comprising rock with permeability suitable for movement of geothermal brine comprises identifying a zone having a permeability of at least 75 Darcy. 
     
     
         6 . The method of  claim 1 , further comprising:
 passing supercritical carbon dioxide through the closed-loop pipe system to produce an energized carbon dioxide stream;   converting the energized carbon dioxide stream to another form of energy.   
     
     
         7 . The method of  claim 1 , further comprising:
 collecting data from the subsurface geologic formation while drilling the second wellbore;   analyzing the data collected while drilling the second wellbore to identify a second target zone;   drilling a third wellbore to the identified second target zone; and   emplacing a second closed-loop pipe system within the third wellbore to harvest energy from the second target zone.   
     
     
         8 . The method of  claim 7 , further comprising:
 passing supercritical carbon dioxide through the closed-loop pipe system to produce an energized carbon dioxide stream;   passing supercritical carbon dioxide through the second closed-loop pipe system to produce a second energized carbon dioxide stream;   converting the energized carbon dioxide stream and the second energized carbon dioxide stream to another form of energy.   
     
     
         9 . The method of  claim 1 , wherein emplacing the closed-loop pipe system comprises disposing a horizontal, vertical, or angled pipe run that at least partially passes through the identified target convective zone. 
     
     
         10 . The method of  claim 1 , wherein the second wellbore has a diameter in the range from 2 inches to 24 inches, and wherein the closed-loop pipe system comprises pipe having an external diameter smaller than the diameter of the second wellbore. 
     
     
         11 . The method of  claim 10 , wherein the second wellbore has a diameter in the range from 4 inches to 14 inches, and wherein the closed-loop pipe system comprises pipe having an external diameter at least 2 inches less than the diameter of the second wellbore. 
     
     
         12 . The method of  claim 1 , further comprising:
 analyzing data for a geologic formation to identify a location of a boundary between a convection zone and a caprock zone; and   wherein the first wellbore is drilled such that the first wellbore is disposed proximate the identified boundary location between the convection zone and the caprock zone.   
     
     
         13 . The method of  claim 12 , further comprising emplacing a second closed-loop pipe system within the first wellbore. 
     
     
         14 . A system for producing geothermal energy, comprising:
 a first closed-loop pipe system emplaced within a convection zone of a heat-producing geologic formation; and   a second closed-loop pipe system emplaced within a fault within the convection zone or within a fault within a caprock zone proximate the convection zone of the heat producing geologic formation.   
     
     
         15 . The system of  claim 14 , wherein the second closed-loop pipe system is emplaced within a wellbore drilled, at least in part, based on data collected during drilling of a wellbore for the first closed-loop pipe system. 
     
     
         16 . The system of  claim 14 , wherein the first closed-loop pipe system is disposed proximate a boundary between a caprock layer and a convection zone. 
     
     
         17 . The system of  claim 14 , further comprising a third closed-loop pipe system emplaced within a fault deep within the convection zone. 
     
     
         18 . A method of producing geothermal energy, comprising:
 drilling a wellbore into a subsurface geologic formation with a drill bit;   measuring properties of the subsurface geologic formation while drilling the wellbore;   analyzing the measured properties of the subsurface geologic formation to identify a target zone;   adjusting a trajectory of the drill bit to pass the wellbore into or through the identified target zone; and   emplacing a closed-loop pipe system within the wellbore to harvest energy from the target zone.   
     
     
         19 . The method of  claim 18 , further comprising:
 analyzing the measured properties of the subsurface geologic formation to identify a second target zone;   drilling a second wellbore to the identified second target zone; and   emplacing a second closed-loop pipe system within the second wellbore to harvest energy from the second target zone.   
     
     
         20 . A method of producing geothermal energy, comprising:
 analyzing measurement while drilling (MWD) data or logging while drilling (LWD) data of a geologic formation to identify a convective geothermal target zone;   drilling a wellbore to the identified convective geothermal target zone; and   emplacing a closed-loop pipe system within the wellbore to harvest energy from the convective geothermal target zone.   
     
     
         21 . A method of producing geothermal energy, comprising:
 disposing two or more closed-loop pipe systems within a geologic formation at targeted locations having different convective heat flow characteristics;   harvesting energy from the geologic formation via the two or more closed-loop pipe systems;   converting the harvested energy via a conversion system configured to utilize the two or more closed-loop pipe systems in tiered manner.   
     
     
         22 . The method of  claim 21 , wherein the two or more closed-loop pipe systems include a higher temperature loop and a lower temperature loop, and wherein the conversion system comprises a CO2 turbine associated with the higher temperature loop and a Rankine cycle system associated with the lower temperature loop. 
     
     
         23 . A method of producing geothermal energy, comprising:
 analyzing formation data to determine two or more target locations having different convective heat flow characteristics;   drilling a first wellbore to a first target location;   disposing a first closed-loop pipe system within the first wellbore to harvest energy from the formation;   drilling a second wellbore to a second target location;   disposing a second closed-loop pipe system within the second wellbore to harvest energy from the formation.   
     
     
         24 . The method of  claim 23 , further comprising:
 converting energy harvested from the first and second closed-loop pipe systems to another form of energy.