| abstract |
Methods and apparatus for spalling a material, for example to thermally drill a wellhole, are provided. Such methods may include directing a fluid having a temperature greater than about 500° C. above the ambient temperature of the material and less than about the temperature of the brittle-ductile transition temperature of the material to a target location on the surface of the material, wherein the fluid produces a heat flux of about 0.1 to about 50 MW/m 2 at an interface between the fluid and the target location, and thereby creating spalls of the material. |