A multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons includes a hollow main drill pipe, a drill bit, four cutting edges, four impeller shafts, four passive impellers and a rotation bracket. Through being uniformly distributed at a peripheral of the drilling rig, four passive impellers contact with a hole wall of a borehole during the drilling process for passively generating relative rotation opposite to the rotation direction of the drill bit, so as to accelerate sufficient mixing of silt and water for forming mud during the drilling process.

A multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons includes a hollow main drill pipe, a drill bit, four cutting edges, four impeller shafts, four passive impellers and a rotation bracket. Through being uniformly distributed at a peripheral of the drilling rig, four passive impellers contact with a hole wall of a borehole during the drilling process for passively generating relative rotation opposite to the rotation direction of the drill bit, so as to accelerate sufficient mixing of silt and water for forming mud during the drilling process, thus enhancing the stirring effect of the drill bit on the mud. The present invention is able to improve the mud discharge efficiency without adding additional power, thus avoiding the blockage of the mud suction pipe and blockage or even breakage of the drill bit due to poor mud discharge during the drilling process.

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.

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.

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.

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.

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.

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.

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.

An excavating machine includes an actuation unit for moving the excavator, a main winch and secondary winch for lifting and lowering the actuation unit. A closed hydraulic circuit or an electric circuit drives the main winch. An open hydraulic circuit drives the secondary winch. A first pressure or current sensor measures fluid pressure or, electric current intensity in the hydraulic or electric driving circuit. A second pressure sensor measures fluid pressure in the open hydraulic circuit. A pressure regulator regulates fluid pressure in the open hydraulic circuit. A control unit executes a combined operating condition with the winches applying a force simultaneously and based on values sensed, controls the pressure regulator so the fluid pressure in the open hydraulic circuit, during the combined operating condition, has a target value that is a function of: the fluid pressure in the closed hydraulic circuit or the current in the electric circuit.