Abstract: Methods and apparatus for excavation of a borehole in a geological formation are provided. Such methods may include providing a thermal system capable of providing substantially hot fluid, and comprising at least one jet nozzle, providing a mechanical drilling system comprising a drill bit, directing the substantially hot fluid through the jet nozzle towards the geological formation causing an altered portion of geological formation to form, and removing the altered portion using the drill bit, thereby creating cuttings and producing a borehole in the geological formation.

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/m2 at an interface between the fluid and the target location, and thereby creating spalls of the material.

Abstract: Methods and apparatus for excavation of a borehole in a geological formation are provided. Such methods may include providing a thermal system capable of providing substantially hot fluid, and comprising at least one jet nozzle, providing a mechanical drilling system comprising a drill bit, directing the substantially hot fluid through the jet nozzle towards the geological formation causing an altered portion of geological formation to form, and removing the altered portion using the drill bit, thereby creating cuttings and producing a borehole in the geological formation.

Abstract: Methods for enhancing existing wells, such as increasing the diameter of an existing well by hydrothermal spallation are provided. Such methods may include providing a housing comprising a reaction chamber and a catalyst element held within the reaction chamber, providing at least one jet nozzle, contacting one or more unreacted fluids or solids with the catalyst element, wherein the unreacted fluid or solid is adapted to react with the catalyst element, thus generating a reacted fluid, and emitting the reacted fluid through the at least one nozzle, wherein the at least one nozzle may be directed to a production zone of an internal wall of the existing well.

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/m2 at an interface between the fluid and the target location, and thereby creating spalls of the material.

Abstract: Methods and apparatus for spalling a geological formation, for example to thermally drill a wellhole, are provided. Such methods may include providing a housing comprising a reaction chamber and a catalyst element held within the reaction chamber, providing at least one jet nozzle, contacting one or more unreacted fluids or solids with the catalyst element, wherein the unreacted fluid or solid is adapted to react over the catalyst element, thus generating a reacted fluid, and emitting the reacted fluid through the at least one nozzle, wherein the at least one nozzle is directed to an excavation site within or on the geological rock formation, thereby creating spalls and/or a reacted rock region.

Abstract: Various rock spallation devices and methods reduce the cost of deep hole excavation. A spallation head has rotating, circumferentially spaced jets. The jets may be combustion flame jets or very hot water. In a combustion embodiment, air and water are delivered to the spallation apparatus downhole in a mixture, and are separated. In a low density embodiment, the borehole is essentially empty. In a high density embodiment, more water is included in the mixture of air and water, and the borehole is filled with fluid. Instead of combustion, the kinetic energy of flowing water at the spallation device can be used to power a turbogenerator that generates electric energy to heat the water and spall the rock. The jets may also be aimed and configured to fuse the excavation material, if spallation is not feasible. New lengths of feed and return pipe can be added while spallation continues uninterrupted, either due to well head alternating equipment, or a downhole relative motion device.

Abstract: The disclosure relates to downhole injection of radioactive .sup.82 Br and monitoring its progress through fractured structure to determine the nature thereof. An ampule containing granular .sup.82 Br is remotely crushed and water is repeatedly flushed through it to cleanse the instrument as well as inject the .sup.82 Br into surrounding fractured strata. A sensor in a remote borehole reads progress of the radioactive material through fractured structure.