Systems and methods for drilling a geothermal well can include drilling a vertical borehole to a target location, drilling a plurality of lateral boreholes, each of which is connected to the vertical borehole, and can include generating a plurality of chambers in at least one of the plurality of lateral boreholes. The techniques can include drilling a plurality of passageways that each provide fluid communication between one of the plurality of chambers in a first lateral borehole and a second lateral borehole of the plurality of lateral boreholes. The techniques can form a fluid circuit for injecting a heating fluid such as water or brine and recovering hot water and steam using a single vertical borehole. The hot water and/or steam can be used to generate electrical power with a geothermal power facility.

Systems and methods for drilling a geothermal well can include drilling a vertical borehole to a target location, drilling a plurality of lateral boreholes, each of which is connected to the vertical borehole, and can include generating a plurality of chambers in at least one of the plurality of lateral boreholes. The techniques can include drilling a plurality of passageways that each provide fluid communication between one of the plurality of chambers in a first lateral borehole and a second lateral borehole of the plurality of lateral boreholes. The techniques can form a fluid circuit for injecting a heating fluid such as water or brine and recovering hot water and steam using a single vertical borehole. The hot water and/or steam can be used to generate electrical power with a geothermal power facility.

The invention relates to variation of concentrations of abrasive particles in a stream of drilling fluid mixed with abrasive particles, passed as an abrasive jet through abrasive nozzle(s) of a drill bit along rotations thereof, to vary the erosive power of the stream along angular sections of the borehole for directional drilling. During subsequent time periods majorities of abrasive particles are alternately deflected into two parallel channels with a different flow resistance. A resulting velocity difference between said majorities makes that the subsequently deflected majorities recombine downstream of the channels, so that high concentration stream portions of the combined majorities are formed which alternate low concentration stream portions. Synchronising the frequency of the stream portions with the rotational velocity of the drill bit results in a consistently higher erosive power of the abrasive jet within a selected angular section of the borehole than outside thereof.

The invention relates to variation of concentrations of abrasive particles in a stream of drilling fluid mixed with abrasive particles, passed as an abrasive jet through abrasive nozzle(s) of a drill bit along rotations thereof, to vary the erosive power of the stream along angular sections of the borehole for directional drilling. During subsequent time periods majorities of abrasive particles are alternately deflected into two parallel channels with a different flow resistance. A resulting velocity difference between said majorities makes that the subsequently deflected majorities recombine downstream of the channels, so that high concentration stream portions of the combined majorities are formed which alternate low concentration stream portions. Synchronising the frequency of the stream portions with the rotational velocity of the drill bit results in a consistently higher erosive power of the abrasive jet within a selected angular section of the borehole than outside thereof.

Systems for drilling or tunneling include an assembly for accelerating a projectile into a region of geologic material. An interaction between the projectile and the geologic material extends a borehole and forms debris. The debris may be reduced in size by moving the debris to a crushing device. The reduced-size debris is then moved toward the surface using fluid movement. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

Systems for drilling or tunneling include an assembly for accelerating a projectile into a region of geologic material. An interaction between the projectile and the geologic material extends a borehole and forms debris. The debris may be reduced in size by moving the debris to a crushing device. The reduced-size debris is then moved toward the surface using fluid movement. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

A drilling assembly includes a hydraulic amplifier assembly, a driver, a bearing housing, and a shaft. The hydraulic amplifier assembly is configured to increase a pressure of a drilling fluid so as to produce a pressurized drilling fluid. The driver is driven by the pressure of the drilling fluid and is configured to rotate a drill bit. The bearing housing is coupled to the driver. The shaft extends through the bearing housing and is configured to be coupled to the drill bit. The shaft is driven to rotate by the driver. The hydraulic amplifier is configured to deliver the pressurized drilling fluid to the drill bit.

A well system for installing highly permeable inclusions at multiple azimuths in anelastic weakly cemented formations. The well system includes a wellbore device interconnected to a tubular string for initiating and propagating of planar inclusions at multiple azimuths into a formation surrounding the wellbore. The well device radially expands to seal against the formation, with the device having multiple openings in its sidewall at differing azimuths for the initiation and propagating of inclusions into the formation by controlled injection of a viscous non-penetrating fluid. The viscous propagating fluid carries proppant to the extremities of the inclusions, creating highly permeable planes at multiple azimuths from the wellbore. The well device is particularly well suited for use in conjunction with anelastic weakly cemented formations.

A well system for installing highly permeable inclusions at multiple azimuths in anelastic weakly cemented formations. The well system includes a wellbore device interconnected to a tubular string for initiating and propagating of planar inclusions at multiple azimuths into a formation surrounding the wellbore. The well device radially expands to seal against the formation, with the device having multiple openings in its sidewall at differing azimuths for the initiation and propagating of inclusions into the formation by controlled injection of a viscous non-penetrating fluid. The viscous propagating fluid carries proppant to the extremities of the inclusions, creating highly permeable planes at multiple azimuths from the wellbore. The well device is particularly well suited for use in conjunction with anelastic weakly cemented formations.

A method of increasing hydrocarbon recovery from a wellbore in a tight formation with greater breakdown pressures, the method including using hydro-jetting to effect a plurality of oriented cavities or discoidal grooves in the horizontal portion of the wellbore to overcome near-wellbore stresses, injecting a thermally controlled fluid into the wellbore to alter the temperature of the formation and lower stresses, and then fracturing the formation to generate a series of fractures that can be formed in a planar formation.