Abstract: An apparatus includes a tube including an inner surface, an inner diameter, and a length. The apparatus also includes a coil spring. The coil spring includes an outer surface, an outer diameter, and a plurality of coil elements arranged along a length of the coil spring. The coil spring can be positioned within the tube and the outer diameter of the coil spring can be less than the inner diameter of the tube. The coil spring can form a waveguide. Related methods of manufacture and systems are also described herein.

Abstract: A method for monitoring and controlling a downhole pressure of a well during formation of a borehole of a well is provided. The method can include monitoring a downhole pressure of a well during formation of a borehole of the well using a millimeter wave drilling apparatus including a waveguide configured for insertion into the borehole. The monitoring can include determining the downhole pressure. The downhole pressure can include an amount of pressure present at a bottom of the well. The method can also include determining a lithostatic pressure of rock surrounding the well at the bottom of the well. The method can further include controlling the downhole pressure relative to the lithostatic pressure of the rock surrounding the well at the bottom of the well. Related systems performing the methods are also provided.

Abstract: An apparatus includes a tube including an inner surface, an inner diameter, and a length. The apparatus also includes a coil spring. The coil spring includes an outer surface, an outer diameter, and a plurality of coil elements arranged along a length of the coil spring. The coil spring can be positioned within the tube and the outer diameter of the coil spring can be less than the inner diameter of the tube. The coil spring can form a waveguide. Related methods of manufacture and systems are also described herein.

Abstract: A method for monitoring and controlling a downhole pressure of a well during formation of a borehole of a well is provided. The method can include monitoring a downhole pressure of a well during formation of a borehole of the well using a millimeter wave drilling apparatus including a waveguide configured for insertion into the borehole. The monitoring can include determining the downhole pressure. The downhole pressure can include an amount of pressure present at a bottom of the well. The method can also include determining a lithostatic pressure of rock surrounding the well at the bottom of the well. The method can further include controlling the downhole pressure relative to the lithostatic pressure of the rock surrounding the well at the bottom of the well. Related systems performing the methods are also provided.

Abstract: A system for monitoring borehole parameters and switching to millimeter wave drilling based on the borehole parameters is provided. The system can include a mechanical drilling apparatus for forming a first portion of a borehole of a well. The first portion of the borehole can be formed based on a permeability of the first portion of the borehole and a temperature within the first portion of the borehole. The system can also include a millimeter wave drilling apparatus configured to inject millimeter wave radiation energy into a second portion of the borehole of the well via a waveguide. The second portion of the borehole can be formed via the millimeter wave drilling apparatus in response to determining the permeability of the first portion of the borehole is below a permeability threshold value and the temperature within the first portion of the borehole exceeds a temperature threshold value.

Abstract: A system for monitoring and controlling downhole pressure of a well borehole relative to a lithostatic pressure of rock surrounding the borehole is provided. The system can include a millimeter wave drilling apparatus including a gyrotron configured to inject millimeter wave radiation energy into a borehole of a well via a waveguide configured for insertion into the borehole. The borehole can be formed via the millimeter wave drilling apparatus and having a downhole pressure monitored at a bottom of the well. The system can also include a compressor fluidically coupled to the borehole and configured to control the downhole pressure via a gas supplied into and/or received from the borehole. The compressor can be configured to control the downhole pressure relative to a lithostatic pressure determined for rock surrounding the well at the bottom of the well.

Abstract: An apparatus includes a tube including an inner surface, an inner diameter, and a length. The apparatus also includes a coil spring. The coil spring includes an outer surface, an outer diameter, and a plurality of coil elements arranged along a length of the coil spring. The coil spring can be positioned within the tube and the outer diameter of the coil spring can be less than the inner diameter of the tube. The coil spring can form a waveguide. Related methods of manufacture and systems are also described herein.

Abstract: An apparatus includes a tube including an inner surface, an inner diameter, and a length. The apparatus also includes a coil spring. The coil spring includes an outer surface, an outer diameter, and a plurality of coil elements arranged along a length of the coil spring. The coil spring can be positioned within the tube and the outer diameter of the coil spring can be less than the inner diameter of the tube. The coil spring can form a waveguide. Related methods of manufacture and systems are also described herein.

Abstract: A system for monitoring and controlling downhole pressure of a well borehole relative to a lithostatic pressure of rock surrounding the borehole is provided. The system can include a millimeter wave drilling apparatus including a gyrotron configured to inject millimeter wave radiation energy into a borehole of a well via a waveguide configured for insertion into the borehole. The borehole can be formed via the millimeter wave drilling apparatus and having a downhole pressure monitored at a bottom of the well. The system can also include a compressor fluidically coupled to the borehole and configured to control the downhole pressure via a gas supplied into and/or received from the borehole. The compressor can be configured to control the downhole pressure relative to a lithostatic pressure determined for rock surrounding the well at the bottom of the well.

Abstract: A method for monitoring and controlling a downhole pressure of a well during formation of a borehole of a well is provided. The method can include monitoring a downhole pressure of a well during formation of a borehole of the well using a millimeter wave drilling apparatus including a waveguide configured for insertion into the borehole. The monitoring can include determining the downhole pressure. The downhole pressure can include an amount of pressure present at a bottom of the well. The method can also include determining a lithostatic pressure of rock surrounding the well at the bottom of the well. The method can further include controlling the downhole pressure relative to the lithostatic pressure of the rock surrounding the well at the bottom of the well. Related systems performing the methods are also provided.

Abstract: A system for monitoring borehole parameters and switching to millimeter wave drilling based on the borehole parameters is provided. The system can include a mechanical drilling apparatus for forming a first portion of a borehole of a well. The first portion of the borehole can be formed based on a permeability of the first portion of the borehole and a temperature within the first portion of the borehole. The system can also include a millimeter wave drilling apparatus configured to inject millimeter wave radiation energy into a second portion of the borehole of the well via a waveguide. The second portion of the borehole can be formed via the millimeter wave drilling apparatus in response to determining the permeability of the first portion of the borehole is below a permeability threshold value and the temperature within the first portion of the borehole exceeds a temperature threshold value.

Abstract: A method for utilizing a millimeter wave drilling apparatus is provided. The method can include monitoring a permeability of a first portion of a borehole of a well while forming the borehole using a drilling apparatus including a drill bit for mechanical removal of material from within the borehole. The method can also include determining to utilize a millimeter wave drilling apparatus including a wave guide configured for insertion into the borehole based at least on the permeability of the borehole falling below a permeability threshold value. The method can further include forming a second portion of the borehole utilizing the millimeter wave drilling apparatus in response to the determining. A method for controlling the downhole pressure of a well is also provided. Related systems performing the methods are also provided.