Method for introducing a borehole

Abstract

Methods for constructing a borehole, in some examples, in the Earth's crust, may involve holding a drill head in the borehole by a linkage. The drill head may include a thermal device that causes material on a base of the borehole to be released from the solid phase via phase change. The released material may be removed in a direction of the Earth's surface. Further, the thermal device may be operated so that it generates a thermal output power high enough to predominantly sublimate material when transitioning out of the solid phase.

1 - 11 . (canceled) 
     
     
         12 . A method for introducing a borehole into Earth's crust, the method comprising:
 holding a drill head in the borehole by a linkage;   operating a thermal device of the drill head so that the thermal device generates a thermal output power high enough to cause material on a base of the borehole to be released from a solid phase via phase change predominantly by way of sublimation; and   removing the released material in a direction of an opening of the borehole.   
     
     
         13 . The method of  claim 12  wherein at least 40% by weight of the material released from the solid phase via sublimation transitions into a gaseous phase. 
     
     
         14 . The method of  claim 12  wherein at least 90% by weight of the material released from the solid phase via sublimation transitions into a gaseous phase. 
     
     
         15 . The method of  claim 12  wherein at least 95% by weight of the material released from the solid phase via sublimation transitions into a gaseous phase. 
     
     
         16 . The method of  claim 12  further comprising monitoring a phase state of the released material at the base of the borehole with a sensor attached to the drill head. 
     
     
         17 . The method of  claim 12  further comprising regulating a quantity of liquefied material on the base of the borehole to a specified nominal value by controlling the thermal output power, wherein the thermal output power is increased for a reduction in the quantity of liquefied material. 
     
     
         18 . The method of  claim 12  comprising operating the thermal device at a heating power of at least 80 kW. 
     
     
         19 . The method of  claim 12  comprising operating the thermal device at a heating power of at least 1,000 kW. 
     
     
         20 . The method of  claim 12  comprising operating the thermal device so as to generate a temperature of at least 2,000 K. 
     
     
         21 . The method of  claim 12  comprising operating the thermal device so as to generate a temperature of at least 5,000 K. 
     
     
         22 . The method of  claim 12  further comprising cooling at least the released material that has been sublimed by a cooling gas stream separate from a plasma jet. 
     
     
         23 . The method of  claim 22  wherein the cooling gas stream forms a gas cushion between the released material that has been sublimed and the drill head. 
     
     
         24 . The method of  claim 23  further comprising blowing the cooling gas stream into a gap between the drill head and the borehole. 
     
     
         25 . A device for introducing a borehole into Earth's crust, the device comprising:
 a drill head;   a linkage for holding the drill head in the borehole;   a thermal device disposed on the drill head that causes material on a base of the borehole to be released from a solid phase via phase change; and   a sensor for monitoring a phase state of the released material at the base of the borehole.   
     
     
         26 . The device of  claim 25  wherein the sensor is attached to the drill head. 
     
     
         27 . The device of  claim 25  wherein the sensor is a photo-optical sensor. 
     
     
         28 . The device of  claim 25  wherein the sensor is a pyrometer. 
     
     
         29 . The device of  claim 25  wherein the thermal device causes the material on the base of the borehole to be released from the solid phase via phase change predominantly by way of sublimation.