Controlling fracture growth during stimulation of subsurface reservoirs using offset wells

Abstract

Systems and techniques may be used to increase recovery of a geothermal energy resource. An example technique includes selecting a first borehole that extends from a surface of the earth into a first location in a geothermal reservoir, conditioning the first borehole by pumping a fluid into or out of the first borehole at a predetermined operating condition to change a property of the geothermal reservoir, and selecting a second borehole that extends from the surface of the earth into a second location in the geothermal reservoir. The example technique may include enhancing permeability of the geothermal reservoir by using a reservoir stimulation technique on the second borehole, wherein a property of a stimulated reservoir volume is controlled by the property of the geothermal reservoir that was changed by conditioning the first borehole.

What is claimed is: 
     
         1 . A method comprising:
 selecting a first well of a geothermal reservoir;   preconditioning the first well by pumping a fluid into or out of the first well to change a property of the geothermal reservoir, the property of the geothermal reservoir being at least one of a reservoir fluid pressure, a reservoir fluid temperature, a reservoir stress, a reservoir poroelastic stress, or a reservoir thermoelastic stress;   selecting a second well of the geothermal reservoir; and   enhancing permeability of the geothermal reservoir by using a first reservoir stimulation technique at the first well and using a second reservoir stimulation technique corresponding with the first reservoir stimulation technique at the second well, the first reservoir stimulation technique and the second reservoir stimulation technique causing fractures to propagate through the geothermal reservoir between the first well and the second well.   
     
     
         2 . The method of  claim 1 , further comprising:
 selecting a third well of the geothermal reservoir;   preconditioning the third well to change the property of the geothermal reservoir based on changes to the geothermal reservoir resulting from the first reservoir stimulation technique and the second reservoir stimulation technique; and   enhancing permeability of the geothermal reservoir using a third reservoir stimulation technique to cause fractures to propagate through the geothermal reservoir away from or towards to the third well.   
     
     
         3 . The method of  claim 2 , wherein the changes to the geothermal reservoir resulting from the first reservoir stimulation technique and the second reservoir stimulation technique comprise at least one of a change to a stress state in the geothermal reservoir, a change to a fracture geometry in the geothermal reservoir, or a change to a pressure field in the geothermal reservoir. 
     
     
         4 . The method of  claim 2 , wherein enhancing permeability of the geothermal reservoir using the third reservoir stimulation technique comprises:
 injecting fluid into the second well to prevent the fractures from propagating towards the second well; and   producing the fluid from the third well to cause the fractures to propagate between the first well and the third well.   
     
     
         5 . The method of  claim 1 , wherein the first reservoir stimulation technique comprises at least one of hydraulic fracturing or hydroshearing, and the second reservoir stimulation technique comprises producing fluid from the second well or injecting fluid into the second well. 
     
     
         6 . The method of  claim 1 , wherein enhancing permeability of the geothermal reservoir comprises:
 creating a hydraulic connection between the first well and the second well using the first reservoir stimulation technique and the second reservoir stimulation technique.   
     
     
         7 . The method of  claim 1 , wherein enhancing permeability of the geothermal reservoir comprises:
 detecting an intersection between the fractures and the second well; and   producing fluid from the second well in response to the intersection to decrease pressure in the fractures.   
     
     
         8 . The method of  claim 1 , wherein enhancing permeability of the geothermal reservoir comprises:
 causing proppant in a fracture in the geothermal reservoir to become immobilized by producing fluid from the second well to drop the reservoir fluid pressure acting on the fracture; and   causing even distribution of the proppant within the fracture in the geothermal reservoir.   
     
     
         9 . The method of  claim 1 , wherein enhancing permeability of the geothermal reservoir comprises:
 manipulating a stress field in the geothermal reservoir through injection or production of fluid to cause the fractures to propagate through the geothermal reservoir between the first well and the second well.   
     
     
         10 . The method of  claim 1 , wherein the property of the geothermal reservoir includes the reservoir fluid pressure, the reservoir fluid temperature, the reservoir stress, the reservoir poroelastic stress, and the reservoir thermoelastic stress. 
     
     
         11 . The method of  claim 1 , wherein the first reservoir stimulation technique comprises injection of fluid at the first well, and the second reservoir stimulation technique comprises production of the fluid from the second well. 
     
     
         12 . A system comprising:
 a first well of a geothermal reservoir, the first well preconditioned by pumping a fluid into or out of the first well to change a property of the geothermal reservoir, the property of the geothermal reservoir being at least one of a reservoir fluid pressure, a reservoir fluid temperature, a reservoir stress, a reservoir poroelastic stress, or a reservoir thermoelastic stress; and   a second well of the geothermal reservoir, wherein permeability of the geothermal reservoir is enhanced by using a first reservoir stimulation technique at the first well and using a second reservoir stimulation technique corresponding with the first reservoir stimulation technique at the second well, the first reservoir stimulation technique and the second reservoir stimulation technique causing fractures to propagate through the geothermal reservoir between the first well and the second well.   
     
     
         13 . The system of  claim 12 , further comprising:
 a third well of the geothermal reservoir, the third well preconditioned to change the property of the geothermal reservoir based on changes to the geothermal reservoir resulting from the first reservoir stimulation technique and the second reservoir stimulation technique.   
     
     
         14 . The system of  claim 13 , wherein the permeability of the geothermal reservoir is enhanced by using a third reservoir stimulation technique to cause fractures to propagate through the geothermal reservoir away from or towards to the third well. 
     
     
         15 . The system of  claim 13 , wherein the changes to the geothermal reservoir resulting from the first reservoir stimulation technique and the second reservoir stimulation technique comprise at least one of a change to a stress state in the geothermal reservoir, a change to a fracture geometry in the geothermal reservoir, or a change to a pressure field in the geothermal reservoir. 
     
     
         16 . The system of  claim 14 , wherein the third reservoir stimulation technique comprises:
 injecting fluid into the second well to prevent the fractures from propagating towards the second well; and   producing fluid from the third well to cause the fractures to propagate between the first well and the third well.   
     
     
         17 . The system of  claim 12 , wherein the first reservoir stimulation technique comprises at least one of hydraulic fracturing or hydroshearing, and the second reservoir stimulation technique comprises producing fluid from the second well or injecting fluid into the second well. 
     
     
         18 . The system of  claim 12 , further comprising:
 a hydraulic connection between the first well and the second well, the hydraulic connection created using the first reservoir stimulation technique and the second reservoir stimulation technique.   
     
     
         19 . A method comprising:
 selecting a well of a geothermal reservoir, wherein a property of the geothermal reservoir is changed in response to a first reservoir stimulation technique, and the property of the geothermal reservoir is at least one of a reservoir fluid pressure, a reservoir fluid temperature, a reservoir stress, a reservoir poroelastic stress, or a reservoir thermoelastic stress;   preconditioning the well by pumping a fluid into or out of the well to change the property of the geothermal reservoir; and   enhancing permeability of the geothermal reservoir using a second reservoir stimulation technique to cause fractures to propagate through the geothermal reservoir away from or towards to the well.   
     
     
         20 . The method of  claim 19 , wherein enhancing permeability of the geothermal reservoir using the second reservoir stimulation technique comprises:
 injecting fluid into an offset well to prevent the fractures from propagating towards the offset well; and   producing fluid from the well to cause the fractures to propagate between the well and an injection well.