Tubular drilling robot

Abstract

The present disclosure relates to apparatuses, a system and a method for high-speed rock drilling, in particular for drilling deep bores. A tubular drilling robot (1) is disclosed comprising a ring drill bit (10) having a hollow cylindrical shape, an electric motor (11) having a hollow cylindrical shape, being mechanically connected to the ring drill bit (10), and a traction unit (12) mechanically connected with the electric motor (11), jacked to the drill bore (200) and configured to hold and / or move the tubular drilling robot (1) for drilling and for direction change.

Description

[0001] TUBULAR DRILLING ROBOT

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a drilling robot for drilling bore holes into the Earth, in particular into hard / crystalline rock, a drilling system, and a method for drilling bore holes using such a drilling robot. The present disclosure is particularly suited to drilling long holes of diameters of up to 500 mm, horizontally or oblique or vertically, e.g. to great depths in the earth which are subject to high temperatures and high pressures.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Current drilling techniques for drilling holes (also referred to as bores) into the earth are inefficient, in particular in that they require a long time. This leads to high production costs, in particular for wellbores through hard rock and / or down to great depths with high temperatures and high lithostatic and hydrostatic pressures.

[0006] Drilling costs are the main reason why many drilling projects are not realized. By reducing drilling costs, new opportunities would open up. Besides the costs related to tooling and material, the long construction time of a drill project is the main reason for its high cost.

[0007] The reason that construction times are long is primarily due to two factors. First, the propulsion speed of the drilling process itself (i.e. the speed at which the drill bit advances through the earth) is slow. Secondly, the time it takes to replace worn drill bits is prohibitive and becomes increasingly prohibitive the longer (e.g., deeper) the bore hole becomes. Therefore, any attempt to significantly reduce the drilling costs must focus on improving the drilling speed, increasing the service life of the drill bits, and / or reducing the amount of time it takes to replace worn drill bits. Ideally, all three problems would be addressed simultaneously.

[0008] Currently, the advancing (forward) speeds of drilling techniques in hard and crystalline rock are in the range of two to five meters per hour. Commercially available is a full arsenal of different drill bits as tricone rotary drill bits, drill bits with PDC plates, drill bits with impregnated diamonds, drill bits for core drilling and so on. Also, alternate drill techniques are known, such as Electro Pulse Boring and Laser Shock Drilling.

[0009] Currently, drilling techniques use drill rigs and drill rods, which extend from the Earth’s surface down to the drill bit, which may be several kilometers down into the Earth. These rods are constructed in a very solid manner to provide the necessary structural rigidity of transferring the drilling torque, withstanding their own weight, withstanding the high forces and temperatures, and as such are firmly attached to each other. This drill rod provides the torque and force which is required for penetration of the drill bit into the rock. The drill rod also supplies the drilling liquid. Every time a damaged or used tool must be replaced, the whole rod must be removed and disassembled as it is removed. For deep wellbores, this can take days. As a result, the costs and efforts involved in drilling remain very high and act as a large or insurmountable engineering and / or financial barrier for many projects which would otherwise require or make use of deep drill bores.

[0010] EP1867831 A1 discloses an apparatus for drilling an underground borehole, that comprises a tubular conveyance system including an electric cable and a supply of drilling fluid, a drilling system including an electrically powered drilling motor providing rotary drive to a drill bit, and a pump. A fluid channel extends from the drill bit up through the motor section and crawler section so that the pump can draw fluid and drilled cuttings up through the drill bit and the inside the drilling assembly. RU84045U1 discloses an electric drill comprising a drill bit, a housing and an electric motor having a rotor with a hollow shaft. A hollow inner drill bit is connected to the hollow shaft. There is also a counter-rotating ring-shaped external drill bit. Washing liquid is pumped to the drill bit to pump a slurry with frangible rock through the drill bit, the hollow shaft and a suction port to a local circulation, from which the drilling mud is discharged through a discharge port to a reservoir. The reservoir is cleaned from the accumulated mud, when the electric drill is raised to the surface.

[0011] SUMMARY OF THE DISCLOSURE

[0012] It is an object of the present disclosure and embodiments disclosed herein to provide one or more apparatuses and one or more methods for rock drilling.

[0013] In particular, it is an object of the present disclosure and embodiments disclosed herein to provide a tubular drilling robot and / or one or more parts or components thereof, a drilling system, and one or more methods for rock drilling, which does not have at least some of the disadvantages of the prior art. This object is achieved by the subject matter of the independent claims. Embodiments and variations are given in dependent claims and claim combinations and in the description, also in conjunction with the drawings. Herein, features disclosed for the method are equally disclosed for the apparatus or system, and vice versa. Furthermore, features disclosed for one aspect of the invention may equally be present or be used in conjunction with another aspect of the invention. As well, each aspect of the invention is also disclosed independent from other aspects of the invention. The present disclosure relates to a tubular drilling robot for earth drilling (i.e., drilling into the Earth). The tubular drilling robot is particularly suited for rock drilling, specifically through hard rock such as granite or gneiss. The tubular drilling robot comprises a ring drill bit having a hollow cylindrical shape and being configured for drilling. Thereby, the ring drill bit produces a solid circular cylindrical drill core, i.e. a solid-material fully cylindrical drill core, and a tubular drill bore, i.e. a ring-cylindrical drill bore or drilling cavity, during drilling. The tubular drilling robot comprises an electric motor having a hollow cylindrical shape, i.e. a ring-cylindrical shape. The electric motor is mechanically connected to the ring drill bit and is configured to provide the rotational power and rotational speed to the ring drill bit for drilling. Thus, during drilling, the electric motor provides the rotational power for drilling.

[0014] In embodiments, the ring drill bit has a hollow cylindrical shape throughout its entire length and provides an inner fully cylindrical cavity for receiving the solid-material fully cylindrical drill core.

[0015] In embodiments, an outer radius of the ring drill bit defines an outer radius of the tubular drill bore, and / or an inner radius of the ring drill bit defines an inner radius of the tubular drill bore.

[0016] In embodiments, an inner radius of the ring drill bit defines an outer radius of the solidmaterial fully cylindrical drill core.

[0017] In embodiments, the tubular drilling robot, in particular the electric motor, has a hollow cylindrical shape throughout its entire length. In particular, the hollow cylindrical shape of the tubular drilling robot is matched in radial dimensions to the hollow cylindrical shape of the ring drill bit. This may include, that the electric motor has an inner radius equal or larger than an inner radius of the ring drill bit, and / or that the electric motor has an outer radius equal or smaller than an outer radius of the ring drill bit.

[0018] The tubular drilling robot as described herein increases the drilling speed by an order of magnitude over known prior art drilling systems, in particular because the electric motor, which fits into the tubular drill bore, is designed to operate at high revolution speeds resulting in high cutting speeds at small cutting depth for all cutting edges and because the tubular drilling robot can be rapidly removed from the drill bore by e.g. a cable and winch mechanism.

[0019] The key elements making the disclosed tubular ring drilling technique that much superior to the prior art are firstly, that all cutting parts, i.e. cutting faces of the ring drill bit. move at high cutting speed and at small incremental cutting step size (allowing much higher drilling speeds and longer tool life times), and secondly that the replacement of worn drill bits may be implemented by a fast cable and winch mechanism instead of the time consuming disassembling and assembling of a large number of heavy rod elements. This also allows to significantly reduce the time for tool replacement.

[0020] The tubular drilling robot may further comprise a power electronics module that can be arranged in a tubular housing or a section thereof, in particular in a tubular housing that is structurally integrated with the tubular drilling robot, and the power electronics module is electrically connected to the electric motor and configured to drive the electric motor. In particular, the power electronics model can be configured to generate three-phase AC power suitable to drive the electric motor. The power electronics module can be designed to be connected to a cable, which cable supplies high voltage DC (or low frequency AC) power. The power electronic module can be designed and protected to withstand challenging environmental conditions, such as temperature, pressure, water and abrasives. The benefits of having a ring drill bit are that high cutting velocities, preferably of over 5 m / s, are achieved at all parts of the ring drill bit in contact with the rock. Common centric drill bits have a cutting velocity approaching zero in the middle. The advantages of high cutting speeds on stock removing techniques are well known.

[0021] As discussed herein, the tubular drilling robot may be removed from the drill bore by cable, allowing for rapid repair and / or replacement if required, as a winch can wind the cable and remove the robot at a far greater speed than prior art core drill bits, which are powered from the surface by a drive shaft, which drive shaft must be lifted and dismantled when removing the core drill bit.

[0022] References to drilling herein are references to the tubular drilling robot in operation, in particular in operation during drilling of the drill bore.

[0023] The tubular nature of the drilling robot means that the drilling robot has a substantially round cylindrical outer shape as well as a substantially round cylindrical inner shape, thereby defining a hollow or ring-cylindrical round cylindrical central cavity. The tubular drilling robot removes material, in particular rock, only in an annular area, thereby forming an annular shaped drill bore (i.e. primary drill bore) with a substantially solid cylindrical inner drill core (i.e. solid-material fully cylindrical drill core), which grows into the drilling robot during its operation. The drill core may be removed, as is explained herein, in one or more segments, such as to achieve a solid or fully cylindrically shaped drill bore, i.e. secondary or final drill bore. The dimensions of the annular area of removed material, i.e. material removed by drilling, (i.e. the inner and outer diameter thereof) are substantially defined by the dimensions of the ring drill bit (i.e. the inner and outer diameter of the ring drill bit). In an embodiment, the tubular drilling robot comprises an optional traction unit mechanically connected to the electric motor. The traction unit is configured to engage with an inner surface of the tubular drill bore and / or an outer surface of the drill core. The traction unit is configured to hold and / or move the tubular drilling robot for drilling. The traction unit provides a lateral force. The sum of all lateral force is preferably greater than 10 kN, more preferably greater than 100 kN.

[0024] In an embodiment, the traction unit includes a bracing mechanism comprising one or more engagement members. The engagement members are configured to engage with the surface of the tubular drill bore and / or the surface of the drill core, thereby providing a holding force which holds the tubular drilling robot in place during drilling. The holding force in particular counteracts the torque and power applied by the electric motor to the ring drill bit during drilling.

[0025] The engagement members may be any mechanical means suitable for grabbing, gripping, holding, or gaining purchase on the drill bore and / or drill core. The engagement members may include hooks, grips, serrations, etc.

[0026] In an embodiment, the traction unit includes an advancing unit configured to exert an advancing force on the ring drill bit during drilling. The advancing force pushes the ring drill bit into the rock, providing a contact force or contact pressure necessary for drilling. The advancing unit relies on the engagement members engaging with the surface of the drill bore and / or drill core.

[0027] The advancing speed and force depend on, among other things, the total diameter of the drill bore, the ring (slot) width, the revolution speed of the drill bit, the number and the contact surfaces of the engaged cutting edges and the depth of cut. For example, the advancing unit is configured to exert an advancing force in the range of 1 kN to 50 kN. Additionally or alternatively, the advancing unit may be configured such that the tubular drilling robot advances at a preferably consistent speed in a range of between 10 cm / min and 200 cm / min.

[0028] For the specific example a drill bore has a diameter of 150 mm, and a slot width of 20 mm (i.e. the ring drill bit is configured such that it moves material in an annular shape having 20 mm width and 150 mm outer diameter).

[0029] In an embodiment, the advancing unit comprises one or more weights, preferably having at least partially a tubular shape (e.g., a tubular section), which engage on the ring drill bit. Thereby, the weights at least partially provide the advancing force on the ring drill bit during drilling.

[0030] In an embodiment, the advancing unit comprises a pressure relieving mechanism, which is configured to relieve and / or control the pressure of the one or more weights on the ring drill bit, in particular during starting and / or stopping of operation of the tubular drilling robot.

[0031] In an embodiment, the advancing unit further comprises at least one advancing engine. The advancing engine is configured to move the ring drill bit axially along the drill bore with respect to a bracing mechanism of the traction unit, in particular the engagement members of the traction unit, for providing a quasi-continuous advancing force on the ring dill bit during drilling. The advancing engine may be implemented by the traction unit.

[0032] What is meant by quasi-continuous advancing force is that the advancing force is substantially continuous during drilling, in that, while small interruptions or discontinuities in the application of the advancing force may occur, even at regular intervals, the advancing force is continually applied to the ring drill bit for the vast majority of the drilling time, i.e. the time when the ring drill bit is turning and drilling into the rock.

[0033] In an embodiment, the advancing unit comprises an advancing screw, e.g., a tubular screw. The advancing engine is configured to drive the advancing screw, which advancing screw mechanically connects the bracing mechanism of the traction unit, in particular the engagement members of the traction unit, with the ring drill bit for providing the quasi- continuous advancing force on the ring dill bit during drilling. The traction unit is thereby configured to pull and / or push the tubular drill robot, either forwards or backwards inside the drill bore.

[0034] In an embodiment, the traction unit comprises at least two engagement members, which are configured to be independently engageable with the surface of the drill bore and / or the surface of the drill core. The engagement members are configured to be axially moveable with respect to the ring drill bit. The first engagement member is configured to engage, during an engagement period, with the surface of the drill bore and / or the surface of the drill core, during which engagement period the second engagement member is not engaged with the surface of the drill bore or the surface of the drill core. The traction unit is thereby configured to pull and / or push the tubular drill robot, either forwards or backwards inside the drill bore, using alternating^ the first and second engagement members.

[0035] In an embodiment, the two engagement members are independently axially moveable with respect to the ring drill bit, preferably via two electrical advancing engines, respectively.

[0036] Preferably, the at least two engagement members are configured to be controllable such that a quasi-continuous advancing force on the ring drill bit is provided during drilling. Preferably, during a first time-period, the first engagement member engages with the drill core and / or drill bore, remaining in a fixed position with respect to the drill bore, and moving in axial direction from a fore position to an aft position in the tubular drilling robot, the fore position closer to the ring drill bit than the aft position. During this given duration, the second engagement member moves from an aft position to a fore position. The first engagement member then disengages while the second engagement member engages. During a second time-period, the opposite occurs, in that the second engagement member, now engaged with the drill core and / or drill bore, moves from a fore position to an aft position, while the first engagement member moves from an aft position to a fore position. The second engagement member then disengages and the first engagement member engages. Thereby, the initial configuration is reached again and the process can begin anew. The fore and aft positions of the first and second engagement members are in particular identical. For example, the fore and aft positions of the first engagement member may both be closer to the ring drill bit in axial direction than the fore and aft positions of the second engagement member. The fore and aft positions, however, may be identical for both engagement members. Alternatively, the fore position of the second engagement member may be arranged between the fore and aft position of the second engagement member. The distance between the fore and aft positions defines the range of motion of the engagement members, i.e. defines the range of motion of the advancing engine or traction unit or tubular drilling robot during one engagement cycle or crawling step.

[0037] The particular engagement member fixed with respect to the drill bore engages with the drill bore, the advancing engine thereby able to provide the advancing force while the other engagement member “resets” itself. Each engagement member may be movable axially from a fore position to an aft position via the advancing engine. Separate advancing engines may be provided for each engagement member.

[0038] Preferably, the first and second time-period overlap. For a short time both engagement members are engaged. The traction unit is configured such that the first engagement member gradually reduces its advancing force to zero while, simultaneously, the second engagement member increases its advancing force towards the pre-defined steady state conditions. The traction unit is configured such that when the first engagement member has reached zero it disengages and starts the “reset” cycle. This control method allows a continuous drilling speed resulting in highest drilling advance and continuously applied advancing force. Cutting edges are treated gently as stress changes and importantly reversals are minimized.

[0039] In an embodiment, the electric motor is an ironless ring electric motor. The ironless ring electric motor forms a hollow central cylinder through which the drill bore protrudes. The ironless ring electric motor has no material of high magnetic permeability inside or extending into a region of its stator coil. In other words, ironless means that the portion which comprises the coil and / or windings of the stator is free of iron and / or free of ferromagnetic materials, and / or free of a material having a relative permeability p / po of for example 4 or higher, preferably of 40 or higher, more preferably of 300 or higher.

[0040] An example of such an ironless ring electric motor which may be used for embodiments of the present invention is disclosed in the publication WO2022194390, which is hereby incorporated by reference in its entirety.

[0041] Specifically, the electric motor may comprise a casing having a substantially cylindrical inner surface and / or outer surface, depending on whether the apparatus has an internal rotor or an external rotor. The term substantially cylindrical includes cylindrical mantle shapes with or without deviations from cylindrical. A ring-cylindrical ironless stator is arranged adjacent to the substantially cylindrical inner surface, in case of an internal rotor, or to the substantially cylindrical outer surface, in case of an external rotor, of the casing, respectively, the stator including a continuous hairpin winding having at least two layers, in particular exactly two layers or a multiple of two layers. The casing functions as a support structure for the ring-cylindrical ironless stator.

[0042] The rotor is arranged preferably coaxially with the ironless stator, either inside the stator in the case of an internal rotor, or outside the stator, in the case of an external rotor. The cylindrical inner and / or outer surface of the casing is or are substantially cylindrical without significant protrusions. In particular, the inner and / or outer surface of the casing and does not have any slots configured to receive the continuous hairpin winding. As the casing does not extend into a region of the stator, in particular not into a region of the continuous hairpin winding, the stator is commonly referred to as an ironless stator, which has no material of high magnetic permeability inside or extending into a region of the winding.

[0043] The continuous hairpin winding comprises preferably wires, which are hairpin-shaped and provide straight wire segments, which run in parallel to a cylinder axis of the continuous hairpin winding, the cylinder axis being coaxial with a rotational axis of the rotor. Next to a first straight segment, on one or both ends of the straight segment, the wire is folded and bent such that a subsequent second straight segment runs anti-parallel at a distance to the first straight segment. The hairpin winding is continuous in that each hairpin wire section, defined by comprising one or two or few straight segments, is continuous with the next hairpin wire section. In particular, there is no necessity for electrical joins created by welding, soldering, or similar technique between the hairpin wire sections. However, the wires of the continuous hairpin winding may ultimately be joined by some welding or similar technique at their ends, e.g. for star-grounding or delta-connecting different phases of the continuous hairpin winding. The continuous hairpin winding has two layers of hairpin wire one upon the other when seen in a radial direction. A given wire changes position, for example, from a first layer to a second layer or vice versa when seen around the continuous stator winding such that the first straight segment is arranged in the first layer and then is folded and bent such that the second or subsequent or next straight segment is arranged in the second layer.

[0044] The internal rotor is itself a ring-cylindrical rotor, such that the electric motor encloses a cylindrically shaped empty region or cavity.

[0045] In an embodiment, the continuous hairpin winding consists of one or more substantially rectangular or flattened wires, which are insulated. Preferably, the wires have an aspect ratio of width to height in a range of 1 :1 - 5:1. More preferably, the aspect ratio is 2:1. The particular aspect ratio chosen depends on the application of the apparatus. The wires are either drawn or rolled. The wires have a conducting core preferably made of copper and an insulating layer on the outside. Further, the geometry of the corner radius of the wire will also depend on the application, in particular on the design of an insulating layer on the outside of the wire.

[0046] The electric motor may be configured with an internal rotor or an external rotor.

[0047] The rotor is preferably implemented with permanent magnets, e.g. rare earth magnets.

[0048] The electric motor is preferably designed as a synchronous electric motor.

[0049] The electric motor is preferably designed to operate at high rotation speeds, preferably higher than 1000 rpm, more preferably higher than 1500 rpm, and at a high torque, preferably higher than 100 Nm, more preferably higher than 200 Nm. The advancing engine may also comprise an ironless ring electric motor configured to drive a tubular screw. The features and considerations described herein with respect to the electric motor, which drives the ring drill bit may also apply to the advancing engine. The advancing engines operates at similar torques but much smaller rotation speeds than the electric motor coupled to the ring drill bit (the drilling engine).

[0050] In an embodiment, the radial outer extension of the ring drill bit is the largest radial outer extension of the tubular drilling robot. The radial inner extension of the ring drill bit is the smallest radial inner extension of the tubular drilling robot. Thereby, the tubular drilling robot is moveable in the drill bore, in particular when the traction unit is unengaged with the surface of the resulting drill bore and / or drill core.

[0051] In an embodiment, the ring drill bit is configured to rotate with a rotational velocity at its radial inner end of at least 5 m / s, preferably at least 10 m / s.

[0052] Preferably, the ring drill bit is configured to rotate at rotational speeds higher than 1000 rpm and more preferably higher than 1500 rpm.

[0053] In an embodiment, the tubular drilling robot is supplied with electrical power from a remote control station via cabling extending along the drill bore. The cables connect the remote control station with the tubular drilling robot. The remote control station is preferably arranged at the Earth’s surface.

[0054] In an embodiment, the cabling is further configured such that the tubular drilling robot may be moved inside the drill bore and / or removed from the drill bore by adjusting a length of the cable inside the drill bore (e.g., using a winching mechanism arranged at the remote control station). In an embodiment, the cabling comprises a plurality of cables configured to provide electrical power as well as control signals and / or sensor signals from and / or to the remote control station to the tubular drilling robot. In particular, the cabling is connected to the integrated or in situ power electronic modules controlling the electric motors for driving the drill bit and the engagement modules as well as the optional plurality of sensors. The electrical power provided is preferably of high voltage and low frequency AC for reducing losses on long distances inside drill bores. More preferably, the electrical power is DC power higher than 4’000 V. The cables for the connection of sensors are preferably shielded and protected to allow for correct signal transmission. Exceeding a certain depth, the cables have to be supported by track cables, connected to the cables at various points, to avoid ruptures of the cable through its own weight. The cables have to be protected to withstand the environmental conditions such as high temperature, high pressure and abrasive fluids.

[0055] In an embodiment, the tubular drilling robot includes one or more sensors. The sensor(s) may be configured to measure a temperature, pressure, operational states of the motors, wear state of the drill bit, the position of the drilling robot etc.

[0056] In an embodiment, the cabling further comprises at least one tube for providing fluid for cooling of electrical components (e.g., the electric motor, the advancing engine, power electronics, sensors) and / or the ring drill bit for cooling of cutting elements and for transporting abrasives away from the ring drill bit.

[0057] In an embodiment, the tubular drilling robot further comprises a control unit. The control unit is configured to control the tubular drilling robot, in particular the electric motor(s) and / or the traction unit. The control unit may be configured to perform one or more predefined functions and / or steps according to instructions stored in a memory of the control unit. Additionally and / or alternatively, the control unit may be controlled or otherwise instructed to perform particular pre-defined steps and / or direction changes and / or functions by control signals received in the control unit from the remote control station.

[0058] In another aspect, the present disclosure also relates to a drill core removal mechanism, which is configured to remove, in particular by breaking-off, after predefined intervals or continuously, at least segments of the drill core, i.e. solid-material drill core, during drilling. The drill core removal mechanism comprises an attachment mechanism configured to engage with the drill core or a segment thereof.

[0059] In an embodiment, the drill core removal mechanism is further configured to transport the removed, in particular broken-off, segments of the drill core at least partially out of the drill bore. For example, the drill core removable apparatus further includes a cable connected to the attachment mechanism, which is configured to pull the attachment mechanism with an attached drill core or segment thereof out of the drill bore.

[0060] In an embodiment, the tubular drilling robot as described herein further comprises a drill core removal mechanism as described herein.

[0061] In embodiments, the drill core removal mechanism can be operated simultaneously with the tubular drilling robot. Thereby, the tubular drilling robot can advance forward into the material, such as rock, while behind the tubular drilling robot the solid-material drill core can be broken-off in segments that can be pulled out of the drill bore.

[0062] In another aspect, the present disclosure also relates to an airstream transport system, which is configured to support the transport of fluid, for example drilling fluid comprising drill cuttings, from a location relatively close to the bottom of the drill bore (in relation to the total drill bore length) to the Earth’s surface during the drilling process. The airstream transport system comprises a pump (which may be implemented as an air compressor) arranged at the Earth’s surface, for example at the remote control station. The pump is designed to pump an airstream of high flow rate and high speed through a tubing down to the bottom of the drill bore. Preferably the airstream transport system comprises a nozzle system which includes at least one nozzle having at least one opening, at or near the tubular drilling robot.

[0063] The nozzle system is designed such that the supplied air fragments the fluid and drill cutting mixture into small droplets which are then dissolved into the large air volume and are lifted by aerodynamic uplift. Preferably, two component jet nozzles are used in which a fluid is fed through a central conduit and mixes with an enveloping gas, thereby dispersing the gas.

[0064] The airstream transport system addresses the problem of having a drill bore filled with fluid (either drilling fluid supplied to the tubular drilling robot for cooling and / or cutting purposes), which, with deep drill bores, would lead to a hydrostatic pressure exceeding the limits within a high-speed electric motor can operate. The drill cuttings or other abrasive particles which are included in the supplied drilling fluid contribute to the hydrostatic pressure. The hydrostatic pressure has to be kept below a limit of about 100 bar. Therefore, the airstream transport system is designed such that the hydrostatic pressure within the drill bore is limited such that the maximum hydrostatic pressure is kept below a defined limit, preferably below 100 bar.

[0065] During the drilling process, the drilling fluid supplied to the tubular drilling robot as disclosed herein, e.g., by the cabling or tubing described herein, removes the drill cuttings from the ring drill bit, in particular from the cutting faces. The drill cuttings are typically fine or very fine (e.g. most particles have a size between 1 Micrometer and 2 Millimeter). They are scattered in a large volume of fluid (e.g., for a drill bore of 150 mm outer diameter and 1 10 mm inner diameter and a drilling speed of 30 m / h, about 6 tons of drill fluid and 1 ton of drill cuttings accumulate per hour).

[0066] The airstream (i.e. air-powered or air driven) transport system is used to lift the fluid and drilling cuttings from around the tubular drilling robot and at least partially out of the drill bore.

[0067] At lesser depths, when the drill bore is not hot enough yet to vaporize the fluid, high volumes of air are supplied via the tubing to the tubular drilling robot, in particular to a location near the bottom of the drill bore. The air supply is designed to create sufficiently high flow rate to transport the fluid / abrasive volume to the Earth’s surface by aerodynamic lift.

[0068] At great drill bore depth, the high temperature of the drill bore wall vaporizes the drill fluid, supporting the air-lift effect. At very great drill bore depth, the vaporization is sufficient to lift substantially all of the fluid and cutting mixture, and little or no pressurized air from the surface is necessary. The lower density of water steam compared to air facilitates the gas transport.

[0069] In an embodiment, the tubular drilling robot further comprises a guidance mechanism configured to control a drill direction of the tubular drilling robot during drilling. With this guidance mechanism, directional drilling can be realized.

[0070] The guidance mechanism may be configured to control the drill direction by unilaterally expanding or contracting a section of the tubular drill robot, jacked up to the engagement members. The torque required for the direction change is provided by the holding force to the drill bore or drill core of the engaging members. In another aspect, the present disclosure also relates to a ring drill bit, which comprises a plurality of diamonds arranged to cut rock material while drilling.

[0071] Cutting includes all types of rock displacement caused by the diamonds interacting with the rock material, including grinding, crushing, scraping and / or gouging.

[0072] In an embodiment, the ring drill bit of the tubular drilling robot described herein comprises the plurality of diamonds.

[0073] The diamonds may be arranged on one or more cutting faces of the ring drill bit. The cutting faces of the ring drill bit include a forward face, an outer face, and an inner face. The outer face faces substantially outwards in radial direction, the forward face faces in axial direction, and the inner face faces substantially inwards in radial direction (i.e., towards the central axis of the tubular drilling robot). The ring drill bit may include bevels and / or chamfers between the faces, and / or further transitional faces.

[0074] In an embodiment, the diamonds are embedded into the ring drill bit, in particular into a structural component of the ring drill bit, which is preferably made of metal.

[0075] In an embodiment, the diamonds include directionally oriented single crystal octahedral diamonds. The single crystal octahedral diamonds may be held in place by a diamond setting, which is designed to hold the single crystal octahedral diamond and may partially wrap around the single crystal octahedral diamond. The diamond setting is preferably made of metal and fabricated by 3D printing or investment casting. The diamonds may be attached to the diamond setting using an active soldering material as described herein. Preferably, the active soldering material is applied in a thin layer, which has a thickness of approximately 10 microns to 500 microns. The diamonds are preferably oriented in a “ship” arrangement, with an edge oriented in cutting direction.

[0076] Preferably, the ring drill bit comprises 100 - 5000 diamonds.

[0077] In another aspect, the present disclosure also relates to a diamond support configured for attachment to a ring drill bit, each diamond support configured to hold one or more diamonds. In particular, the ring drill bit with attachment of the diamond support is part of the tubular drilling robot as disclosed herein.

[0078] In an embodiment, the ring drill bit includes at least one diamond support, each diamond support configured to hold one or more of the diamonds. The diamond support may comprise one or more diamond settings. The diamonds may alternatively be held in the diamond support directly by an active soldering material, which fixes the diamonds in place.

[0079] The active soldering material preferably comprises a combination of copper, silver and titanium. In an example, the active soldering material comprises in particular 30% - 40% percent copper by weight, 60% - 70% percent silver by weight and 1% - 5% percent titanium by weight.

[0080] In an embodiment, the diamonds, the diamond setting and / or the diamond support, which comprises the diamonds, are arranged on the ring drill bit in a pre-defined pattern. For example, the pre-defined pattern includes one or more rows of diamonds, the rows being oriented radially, axially and / or circumferentially. In other words, the rows may run parallel to a radial direction of the ring drill bit, parallel to an axial direction of the ring drill bit, and / or be circular circumferential rows. The rows do not necessarily need to be uninterrupted or continuous, but may include regular and / or irregular gaps. In an embodiment, two adjacent rows are staggered with respect to each other, such that the diamonds of a first row line up with a gap between diamonds in a second row (this is also referred to as two-dimensional hexagonal close packing). Thereby, a high surface density of diamonds is achieved.

[0081] The diamonds may be arranged in groups, each group including at least two rows of diamonds, each row having a defined length, each group having a defined position and / or orientation on the ring drill bit radially and / or axially, at least two groups having a different position and / or orientation (i.e. the two groups are not arranged in a rotationally symmetric manner).

[0082] The diamonds are preferably large diamonds, preferably having a size in a range of 0.5 mm to 1 . 5 mm.

[0083] In an embodiment, each diamond support comprises at least one magazine configured to house a sequence of diamonds such that, during drilling, once a particular diamond is at least partially worn, fractured, and / or lost, a subsequent diamond in the sequence is made available for drilling. The sequence of diamonds may be arranged in a straight and / or staggered fashion.

[0084] The magazine, and thereby the sequence of diamonds, is preferably oriented towards a cutting surface of the ring drill bit. For example, the magazine is oriented such that the sequence of diamonds is orthogonal, or substantially orthogonal, to a particular cutting surface.

[0085] The diamond support may include a number of adjacently arranged magazines, in particular arranged in the same direction. Preferably, the ring drill bit, in particular the diamond setting, diamond support and / or magazine, is configured such that the diamonds protrude at least 0.1 mm, preferably 0.3 mm. The diamonds protrude beyond the diamond setting, support, magazine, and / or active soldering material such that there is sufficient space for a drilling fluid to penetrate and flush out the abraded material.

[0086] The ring drill bit may include a plurality of diamond supports configured for different cutting faces.

[0087] The magazine may include a biasing member configured to feed the diamonds in sequence.

[0088] The magazine may itself be made at least partially of the active soldering material, which is worn simultaneously with a particular diamond during drilling, such that the subsequent diamond in the sequence is presented once the particular diamond is at least partially worn, chipped, broken, fragmented, and / or lost.

[0089] The magazine may be in the form of an open container, which houses the diamonds, the diamonds being fixed to the open container by an active soldering material. The container may in particular be made at least partly of metal.

[0090] In another aspect or embodiment, the ring drill bit comprises a radial adaptation mechanism, which is configured to adapt the radial position of at least one cutting portion of the ring drill bit, in particular of the diamond support, from a first clearance configuration to a second cutting configuration, wherein the clearance configuration enables a movement of the ring drill bit along the drill bore, in particular a downwards movement of a fresh ring drill bit with unworn diamonds along the drill bore. The radial adaptation mechanism addresses an issue in the prior art where, as the outer diamonds are worn, the diameter of the drill bore reduces. The drill bore therefore is not a perfect cylinder with constant diameter, but typically has a conical shape. Once the ring drill bit is replaced, the new drill bit does not immediately fit all the way down the drill bore, and therefore time must be spent for the new ring drill bit to “smooth” the drill bore until it can continue adding depth / length to the drill bore. The radial adaptation mechanism allows for the diameter of the ring drill bit to be reduced such that it can fit through a narrowed section of the drill bore.

[0091] The first clearance configuration may be at a lesser distance from the central axis than the second cutting configuration for a specific cutting portion of the ring drill bit, in particular for the specific cutting portion configured to cut and / or grind the surface of the drill bore.

[0092] The first clearance configuration may be at a greater distance from the central axis than the second cutting configuration for another specific cutting portion of the ring drill bit, in particular for a specific cutting portion configured to cut the surface of the drill core.

[0093] In an embodiment, the radial adaptation mechanism includes a passive mechanism, which is configured to move the ring drill bit into the second cutting configuration when an axial force in the advancing direction is applied.

[0094] In an embodiment, the radial adaptation mechanism includes a carriage which includes the cutting portion, the carriage being slidably arranged in a guiding slide of the ring drill bit, wherein the guiding slide is arranged at an inclination with respect to the axial direction of the drill bit, thereby enabling to adapt the radial position of the cutting portion from the clearance configuration to the cutting configuration. The radial adaptation mechanism is preferably configured to be passive, such that the guiding slide moves depending only on the pressure or lack thereof exerted on the ring drill bit.

[0095] In another aspect, the present disclosure also relates to a drilling system for drilling bore holes into the Earth. The drilling system comprises a tubular drilling robot, in particular the tubular drilling robot as described herein, and a remote control station. The remote control station is arranged on the Earth’s surface and is connected to the tubular drilling robot via cabling providing electrical power to the tubular drilling robot. The cabling may further provide control signals to the tubular drilling robot and / or sensor signals, for example to communicate the environmental conditions at the tubular drilling robot or a state of the tubular drilling robot.

[0096] In addition to the cabling, tubing might be provided for transporting fluid to and from the tubular drilling robot.

[0097] In addition to the cabling, tubing might be provided for transporting compressed air to and / or into the drill bore above the top of the drill core, preferably to a nozzle system of an airstream transport system as described herein. in another aspect, the present disclosure also relates to a method for drilling a drill bore into the Earth. The method comprises a number of steps. The method includes providing a tubular drilling robot, in particular a tubular drilling robot as described herein. The method includes drilling, using the tubular drilling robot, the drill bore into the Earth. During the drilling step, a hollow cylindrical drill bore can be produced. In particular, the hollow cylindrical drill bore can surround a solid-material fully cylindrical drill core. Such solid-material drill core can be removed by using other techniques than drilling. In an embodiment, the method further comprises drilling, using a tubular drilling robot as described herein, a further drill bore into the Earth (which may be referred to as an ascending bore), such that the further drill bore is fluidically connected to the drill bore, thereby providing a closed-loop flow path designed for circulating a working fluid. The closed-loop flow path may be integrated into a geothermal energy extraction system, preferably an Advanced Geothermal System (AGS).

[0098] Preferably, the closed-loop flow path comprises the drill bore (which may be referred to as a heat absorption bore) which extends from the Earth’s surface into a geological formation. The closed-loop flow path comprises at least one further drill bore (which may be referred to as an ascending bore) which also extends from the Earth’s surface into the geological region. The descending bore and the ascending bore are directly fluidically connected such that the working fluid flows along a continuous flow path, through the Earth, as defined by the heat absorption bore and the ascending bore.

[0099] In an embodiment, the closed-loop flow path includes more than one heat absorption bore and / or more than one ascending bore, the plurality of bores fluidically connected to each other underneath the Earth’s surface by way of a manifold.

[0100] In an embodiment, the geothermal energy extraction system comprises a plurality of closed-loop flow paths.

[0101] In an embodiment, the method further comprises the step of removing the fluid used for cooling and drilling and the drill cuttings. Preferably the fluid and the cuttings are removed using an airstream transport system as described herein.

[0102] In an embodiment, the fluid and the drill cuttings are removed using a plurality of sump pumps in a cascaded arrangement, each cascade step comprising a compensating reservoir. In an embodiment, the method further comprises the step of removing, from the drill bore, at least segments of the drill core. Preferably, the drill bore segments, i.e. solid-material drill bore segment, are removed using a removal mechanism. In particular, the step of removing comprises breaking-off segments of the drill core; and / or the step of removing comprises a step of transporting the removed, in particular broken-off, segments of the drill core at least partially out of the drill bore.

[0103] In an embodiment, the method further comprises the step of sealing, at least partially, the surface of the resulting drill bore.

[0104] In an embodiment, the step of sealing comprises continuously sealing the surface by providing on the surface of the resulting drill bore fine-ground debris. The fine-ground debris preferably comprises debris resulting from drilling of the drill bore, in particular including ground rock particles with particle sizes in the range from 1 Micrometer to 2 Millimeters, preferably in the range from 1 Micrometer to 0.1 Millimeter.

[0105] BRIEF DESCRIPTION OF THE DRAWINGS

[0106] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings in which:

[0107] Fig. 1 shows a front view of a tubular drilling robot;

[0108] Fig. 2 shows a side view of a tubular drilling robot;

[0109] Fig. 3 shows a side section view of a tubular drilling robot; Fig. 4 shows a side section view of a front part of a tubular drilling robot, in particular the ring drill bit and part of the electric motor;

[0110] Fig. 5 shows a side section view of a tubular drilling robot;

[0111] Fig. 6 shows a side section view of a middle part of a tubular drilling robot, in particular part of the electric motor and part of the traction unit;

[0112] Fig. 7 shows a side section view of a rear part of a tubular drilling robot, in particular part of the traction unit;

[0113] Fig. 8 shows a side section of a rear part of a tubular drilling robot, in particular the traction unit in a fore position; Fig. 9 shows a side section of a rear part of a tubular drilling robot, in particular the traction unit in a deployed position;

[0114] Fig. 10 shows a perspective view of a tubular drilling robot with a partial cutout section;

[0115] Fig. 11 shows a section view of the traction unit in a disengaged fore position;

[0116] Fig. 12 shows a section view of the traction unit in a deployed fore position;

[0117] Fig. 13 shows a section view of the traction unit in a deployed aft position;

[0118] Fig. 14 shows a section view of an engagement member in a first position; Fig. 15 shows a section view of an engagement member in a second position;

[0119] Fig. 16 shows a section view of an engagement member in a third position;

[0120] Fig. 17 shows a section view of a ring drill bit of a tubular drilling robot, in a drill bore, in the cutting configuration, in which the ring drill bit has worn out;

[0121] Fig. 18 shows a section view of a ring drill bit of a tubular drilling robot, in a drill bore, in a clearance configuration and moving into a cutting configuration, in which the ring drill bit has new diamonds;

[0122] Fig. 19 shows a section view of a ring drill bit of a tubular drilling robot of Fig. 18, now having reached the cutting configuration;

[0123] Fig. 20 shows a section view of a ring drill bit of a tubular drilling robot of Fig. 18, having begun cutting;

[0124] Fig. 21 shows a section view of a ring drill bit of a tubular drilling robot of Fig. 18, further along in the cutting;

[0125] Fig. 22 shows a schematic top view of part of a ring drill bit, in particular a diamond support comprising a plurality of new single crystal octahedral diamonds in a row;

[0126] Fig. 23 shows a schematic top view of part of a ring drill bit as in Fig. 22, comprising a plurality of worn diamonds in a row; Fig. 24 shows a schematic top view of part of a ring drill bit, in particular a diamond support comprising two rows of diamonds, or two diamond supports each comprising a single row of diamonds, the second row staggered parallel to the first row by half the gap of two diamonds;

[0127] Fig. 25 shows a schematic side on section view of a ring drill bit, in particular showing the arrangement of two rows of diamonds on a diamond support staggered in height by a quarter of the size of the diamonds;

[0128] Fig. 26 shows a schematic side on section view of a magazine of a diamond support showing multiple wells, each including a column of diamonds;

[0129] Fig. 27 shows a schematic top view of a magazine of a diamond support as in Fig. 26;

[0130] Fig. 28 shows a schematic side on section view of a magazine of a diamond support showing a single well, including several columns of diamonds staggered in height;

[0131] Fig. 29 shows a perspective view of a ring drill bit including a plurality of diamond supports arranged circumferentially around the ring drill bit;

[0132] Fig. 30 shows a perspective section view of the ring drill bit of Fig. 29, showing a section view through a particular diamond support;

[0133] Fig. 31 shows a perspective view of a first type of diamond support, showing the guiding slide of a radial adaptation mechanism for an outer element; Fig. 32 shows a perspective view of a second type of diamond support, showing the guiding slide of a radial adaptation mechanism for an inner element;

[0134] Fig. 33 shows a highly schematic diagram illustrating a drilling system including a tubular drilling robot in deployment which is tethered by cable to a remote control station;

[0135] Fig. 34 shows a highly schematic diagram illustrating a section view of a tubular drilling robot including a slide seal ring, guiding the drill fluid towards the ring drill bit;

[0136] Fig. 35 shows a highly schematic diagram illustrating a section view of a tub- ular drilling robot including a closed prolongation tube guiding the drill fluid through the ring drill bit and acting as transport shell for the drill core;

[0137] Fig. 36 shows a highly schematic diagram illustrating an airstream transport system including a nozzle which is connected, by a tube, to an air compressor; and

[0138] Fig. 37 shows a flow diagram illustrating a number of exemplary steps for drilling a drill bore using a tubular drilling robot. DESCRIPTION OF THE DRAWINGS

[0139] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0140] Figures 1 to 3 show a front view and two side views, respectively, of a tubular drilling robot 1 . The tubular drilling robot 1 has an overall substantially circular cylindrical shape. The centerline C of the tubular drilling robot 1 extends, from a distal end to a proximal end in the positive z-direction, while the lateral dimensions x, y extend in a radial direction.

[0141] The tubular drilling robot 1 is a self-contained and self-motorized apparatus which is powered by a cable and is distinguished from prior art ring drilling rigs for example in that it includes a tubular electric motor 1 1 as described herein.

[0142] The tubular drilling robot 1 has a proximal end comprising the ring drill bit 10. The ring drill bit 10 is ring-shaped, i.e. has a tubular, hollow-cylindrical shape. The dimensions of the ring drill bit 10 are defined by an inner radius and an outer radius. The difference between the outer and inner radius may be referred to as the width or thickness of the ring drill bit. The outer radius substantially defines the radius of the drill bore 200 produced by the tubular drilling robot 1 when drilling. The inner radius substantially defines the radius of the drill core 201 produced by the tubular drilling robot 1 when drilling. The ring drill bit 10 as described herein may be provided separately to the tubular drilling robot 1 , i.e. as an object distinct from the tubular drilling robot 1. In particular, the ring drill bit 10 may be disconnected from the tubular drilling robot 1 for repair and / or replacement. As such, ring drill bits 10 may be provisioned as spare parts for the tubular drilling robot 1 .

[0143] The ring drill bit 10, when drilling, removes material only in a ring-shaped area (which extends into a tubular shaped volume as drilling progresses). Preferably, the outer radius and the inner radius of the ring drill bit 10 are large compared to the width. The width is mainly determined by practical design and fabrication limitations related to the electric motor described herein. Preferably, the width is as small as possible. With an ironless electric motor, the width can be as small as 20 mm. The benefits of a relatively small width of the ring drill bit are that only a small portion of rock has to be removed (requiring less power and torque of the electric motor) and, even more importantly, that the innermost cutting parts (i.e. the inner gauge cutting face) operate still at comparably high cutting speeds as the outermost cutting parts, thereby providing for overall high drilling speeds at small cutting depths promoting long tool lifespans.

[0144] The inner and outer radius of the ring drill bit 10 substantially constrains the maximal inner and outer dimensions of the tubular drilling robot 1 . In other words, the ring drill bit 10 defines an overall enveloping circular cylindrical shape of the tubular drilling robot 1. This is because the dimensions of the ring drill bit 10 define the dimensions of the drill bore 200 and the dimensions of the drill core 201 , and the tubular drilling robot 1 as a whole must be able to move within the drill bore 200, in particular it must be able to follow the excavated space produced by the ring drill bit 10, and must be able to be withdrawn from the drill bore 200. There is at least one exception to this, however, in the traction unit 12 described below in more detail, at least part of which extends beyond the radial dimensions of the ring drill bit 10, in particular when engaged with the drill core 201 and / or the drill bore 200 such as to hold and / or move the tubular drilling robot 1 .

[0145] The ring drill bit 10 is connected to an electric motor 11 of the tubular drilling robot 1 . The electric motor is a tubular cylindrical electric motor 11 , which is preferably arranged adjacent to the ring drill bit 10 in a distal direction (i.e. in the negative z-direction).

[0146] The electric motor is preferably configured to rotate at 1000 - 5000 rpm, preferably 2000 rpm. The electric motor 11 is preferably designed to provide a torque in the range of 50 - 1000 Nm, for example a torque of 200 Nm. An electric motor 11 having this performance capability has been realized with a radial width (thickness) of 15 mm, thereby fitting inside a tubular drilling robot 1 having an overall maximal radial width of 20 mm.

[0147] The ring drill bit 10 may be directly interconnected with the electric motor 11 , for example by way of a drill bit coupling 104. The drill bit coupling 104 may include features and / or components which are part of the ring drill bit 10 and / or features and / or components which are part of the electric motor 11 . In particular, the drill bit coupling 104 may include mating components, e.g., female and male components, where the female components may be arranged on the ring drill bit 10 and male components may be arranged on the electric motor 11 , or vice-versa.

[0148] Preferably, the ring drill bit 10 is fastened to the electric motor 11 in a releasable manner, such that the ring drill bit 10 may be replaced for repair and / or replacement. For example, the drill bit coupling 104 may be a releasable coupling.

[0149] The drill bit coupling 104 is preferably a hollow circular coupling 104, and / or includes coupling members 104 distributed in a circular manner. The hollow circular coupling 104 has an inner radial extension greater than the inner radial extension of the ring drill bit 10. For example, the drill bit coupling 104 may comprise a plurality of mechanical fasteners, in particular distributed in a circular manner, preferably at a radial distance from the centerline C of the ring drill bit 10 substantially equal to a radial distance of the bulk of the ring drill bit 10. The mechanical fasteners may include threaded fasteners, bolts, such as captive screws and / or bolts. The ring drill bit 10 may comprise a plurality of circularly distributed holes or recesses for accepting the mechanical fasteners.

[0150] Alternatively or additionally, the drill bit coupling 104 may comprise a screw thread connection. For example, the ring drill bit 10 may include a male thread on an inner or outer surface configured to engage with a female thread of the electric motor 1 1 .

[0151] Alternatively or additionally, the drill bit coupling 104 may comprise a clamping mechanism, such as a shank and chuck mechanism (which may have one or more chuck jaws).

[0152] The drill bit coupling 104 may comprise one or more splines which define one or more ridges or tooth’s which engage with counterpart recesses or grooves to align the ring drill bit 10 with the electric motor 11 and / or for purposes of torque transfer. For example, the drill bit coupling 104 may comprise the ring drill bit 10 having male splines and the electric motor 11 having female splines.

[0153] The tubular drilling robot 1 comprises a traction unit 12. The traction unit is arranged downstream from the ring drill bit 10 and the electric motor 1 1 . Preferably, the traction unit 12 is interconnected with the electric motor 11. The traction unit 12 is configured to hold the tubular drilling robot 1 in place during drilling and / or to move the tubular drilling robot 1 in drilling direction during drilling. In particular, the traction unit 12 mechanically engages with the drill bore 200 and / or the drill core 201 to provide a holding force sufficient such that the tubular drilling robot 1 does not rotate in the drill bore 200 during drilling (i.e. such that the drilling torque is countered). The traction unit 12 is further configured to provide an advancing force which is transferred to the ring drill bit 10 for drilling.

[0154] In an embodiment, the advancing force is provided such that the tubular drilling robot 1 advances steadily. The overall average drilling speed may be over 10 meters per hour (m / h), in fact up to about 60 m / h through granite. The total advancing force provided both by the weight of the tubular drilling robot 1 (which may include weighted elements to further increase the weight) and the traction unit 12 is on the order of several 10 kN (e.g., in the range of 30 kN). The sum of the lateral holding forces to prevent slipping is typically an order of magnitude higher than the advancing force (e.g., in the order of 10 times higher).

[0155] The tubular drilling robot 1 may comprise a power electronics module (not shown) which is configured to provide three phase AC power to the electric motor 1 1 . The tubular drilling robot 1 may further comprise a connector for connecting the power electronics module and / or the electric motor 11 to a remote control station (not shown) by cable. The cable may further be configured to lift and / or pull the tubular drilling robot 1 from the drill hole using a winch which is part of the remote control station.

[0156] The tubular drilling robot 1 is supplied with drilling fluid from the remote control station 14 by a tube. The drilling fluid may, in an embodiment, be substantially water.

[0157] The drilling fluid is used in part to cool the tubular drilling robot 1 , in particular the electric motors 11 , 126, the power electronics module(s) and / or the sensors.

[0158] The fluid is also used to remove or flush drill cuttings from around the ring drill bit 10, specifically from the cutting faces 101 . In an embodiment, part of the fluid, in particular a part used for flushing the drill cuttings is fed or supplied to an inner part of the tubular drilling robot 1 by openings on an inner surface of the tubular drilling robot 1 . A sealing member prevents a flow of the fluid upwards on the inside. Specifically this sealing member may be implemented as a slide seal ring 205 attached to an inner upper part of the tubular drilling robot 1 and arranged to seal a gap between the tubular drilling robot 1 and the drill core 201. Alternatively or additionally, a closed prolongation tube 206 is arranged over the top of the drill core 201 tightly fixed to the tubular drilling robot 1. The drilling fluid is fed into the closed prolongation tube 206 and is then forced to pass between the ring drill bit 10 and the bottom of the drill bore 200 (the drill bore ground) to the outside of the tubular drilling robot 1 , thereby washing out the drill cuttings and then moving, outside the tubular drilling robot 1 , upwards along the drill bore 200.

[0159] Alternatively, the drilling fluid can be supplied or fed to the outside of the tubular drilling robot 1 . Specifically, the sealing members are arranged accordingly such that the drilling fluid passes along the outside of the tubular drilling robot 1 towards the ring drill bit 10, passes around the front of the ring drill bit 10, then passing back along the inside of the tubular drilling robot 1 , thereby flushing away the drill cuttings and also cooling the tubular drilling robot 1 .

[0160] The tubular drilling robot 1 has a tubular structure. The tubular structure is connected to the other components and is designed to provide the overall shape and ensure the structural integrity of the tubular drilling robot 1 . The tubular structure is load bearing and is designed in particular to withstand the mechanical forces the tubular drilling robot 1 is subject to during drilling. The tubular structure may comprise structural elements such as walls, sections, struts, or members. The tubular structure may be made of metal, in particular machined metal. The tubular structure is connected to the parts and / or components of the tubular drilling robot 1 described herein. The tubular structure may be directly interconnected with these parts and / or components, or these parts may be rotatably connected to the tubular structure. At least part of the tubular structure may be designed to rotate with respect to another part of the tubular structure. For example, the ring drill bit 10 may provide part of the tubular structure yet be designed to rotate with respect to a stator of the electric motor 1 1.

[0161] At least some parts of the tubular structure may be provided by particular components of the tubular drilling robot 1 explicitly described herein, for example the stator 11 1 of the electric motor 11 may be considered part of the tubular structure of the tubular drilling robot 1 . The rotor 110 of the electric motor 1 1 may also be considered as part of the tubular structure of the tubular drilling robot 1 .

[0162] The tubular structure supports and / or provides an inner round cylindrical shell. The tubular structure supports and / or provides an outer round cylindrical shell.

[0163] Figure 4 shows a side section view of a front part of the tubular drilling robot 1 , in particular including the ring drill bit 10 and the electric motor 11. The ring drill bit 10 as shown is a schematic representation of such a ring drill bit 10 and does not necessarily show all features of the ring drill bit 10. In particular, the cutting faces 101 , 101 A, 101 B, 101 C may be implemented differently than depicted, in particular with a different geometry (for example as described below with reference to Figs. 29 and 30).

[0164] The ring drill bit 10 includes a front cutting face 101 A which substantially faces the drilling direction (i.e. the positive z-direction). The front cutting face 101 A may have a flat profile and / or a curved profile (in particular a convex profile). The ring drill bit 10 includes an outer gauge cutting face 101 B arranged on an outside edge of the ring drill bit 10 and which defines the radius of the drill bore 200. The ring drill bit 10 includes an inner gauge cutting face 101 C arranged on an inside edge of the ring drill bit and which defines the radius of the drill core 201 , i.e. the inner radius of the drill bore 200.

[0165] The cutting faces 101 , 101 A, 101 B, 101 C of the ring drill bit 10 may include one or more transitional faces between the inner gauge cutting face 101 B, the front cutting face 101 A, and / or between the front cutting face 101 A and the outer gauge cutting face 101 C. The transitional cutting faces may be in the form of bezels, which may include flat and / or curved sections.

[0166] The cutting faces 101 , 101 A, 101 B, 101 C may not necessarily be rotationally symmetric, i.e. they may include one or more undulations, channels, slits, or gaps in axial (z-) and / or radial (x-y) direction. The undulations may provide one or more channels, such that drilling fluid may flow along or past the cutting faces 101 such as to cool the drill bit and to carry away drilling debris.

[0167] The ring drill bit 10 may be structurally divided into two sections including a base section 103 and a coupling section, which may form part of the drill bit coupling 104 described herein.

[0168] The base section 103 includes the cutting faces 101 and is arranged at the front of the ring drill bit 10, while the coupling section 104 is arranged at the back of the ring drill bit 10, i.e. in negative z-direction relative to the base section 103.

[0169] The base section 103 has an overall hollow cylindrical shape, however the inner and / or outer radius of the base section 103 may vary. In particular, the inner radius of the base section 103 and / or the outer radius tapers in the negative z-direction.

[0170] The coupling section 104 also has an overall hollow cylindrical shape. The ring drill bit 10, in particular the base section 103, is preferably made of metal. For example, the base section 103 may be made substantially of stainless steel. Manufacturing techniques may include 3D printing, machining, and / or investment casting. The base section 103 may include one or more areas, made of tungsten carbide, in particular mantle areas, i.e. those which form, at least partly, the cutting faces 101. These areas may define a cutting face support section 102.

[0171] In an embodiment, the ring drill bit 10 includes cutting faces 101 made of tungsten carbide or sintered polycrystalline diamonds as PCD plates, which may be used for softer rocks where single crystal diamond cutting bits are not necessary.

[0172] The coupling section 104, which may include part of the drill bit coupling 104, is also preferably made of metal, for example stainless steel.

[0173] The ring drill bit 10 preferably includes a plurality of diamonds 1010 arranged on the cutting faces 101. The diamonds 1010 may be embedded into the base section 103 of the ring drill bit.

[0174] The diamonds 1010 may be octahedral single crystal diamonds. The diamonds 1010 may be attached to the base section 103 by way of diamond settings which receive and / or grasp at least part of the diamonds 1010. The diamond settings may have a semi- octahedral shape. The diamonds 1010 may be secured to the diamond settings mechanically, i.e. by having parts of the diamond settings grasp the diamonds 1010, and / or by solder, in particular an active soldering material. Further details of the ring drill bit 10 are explained herein.

[0175] For example, between 200 - 3000 octahedral single crystal diamonds 1010, preferably 300 - 1000, each having a size of 1 .0 to 1 .5 mm, are attached to a ring drill bit 10 having an outer diameter of 150 mm and an inner diameter of 1 10 mm. The diamonds 1010 are attached to the base section 103 using an active soldering material of 35% copper, 63% silver and 2% titanium. The diamonds were arranged in a “ship” arrangement in which one edge of each diamond is oriented in cutting direction (i.e., in the circumferential direction of rotation). The clearance between the cutting point of the diamonds 1010 and the surface of the base section 103 of the ring drill bit 10 is more than 0.3 mm. Using such a drill bit, drilling speeds in granite of 60 m / h were achieved.

[0176] The electric motor 11 comprises a rotor 1 10 and a stator 11 1. The electric motor 1 1 as shown in the Figures has an interior rotor 1 10, however an exterior rotor 1 10 is also possible.

[0177] The rotor 1 10 has a hollow circular cylindrical, i.e. tubular, shape. The rotor 1 10 comprises a plurality of permanent magnets.

[0178] The rotor 110 is mechanically connected to the stator 1 1 1 via bearings. The bearings are preferably arranged either side of the rotor 110. The bearings include, for example, front rotor bearings 1 12 and rear rotor bearings 1 13 (not shown). The front and / or rear rotor bearings 1 12, 113 may be implemented each as a pair of angular contact bearings in an O configuration, such that the axial advancing force (i.e., drilling force) is met.

[0179] The tubular drilling robot 1 further includes, at each bearing, a bearing seal designed to prevent water and / or drill cuttings ingress or other environmental contamination.

[0180] The stator 1 11 has a hollow cylindrical shape complementary to the shape of the rotor 1 10, such that the stator 1 11 , in particular the stator windings, are in close proximity (with a small air gap) to the rotor 1 10, such as to efficiently generate torque.

[0181] The stator windings are preferably hairpin windings. This has the benefit of allowing for a high overall packing density of stator windings and allowing for high current in the stator windings. The hairpin windings are preferably implemented as continuous hairpin windings, which have the advantage of requiring fewer welding joins. A stator winding suitable for the present electric motor 11 is described in detail in the patent publication WO2022194390, which is hereby incorporated by reference in its entirety.

[0182] Figure 5 shows a section view of the tubular drilling robot 1 , in particular showing the detailed views M and P of Figures 6 and 7, respectively.

[0183] Figure 6 shows a section view of the tubular drilling robot 1 of section M as indicated in Figure 5. Shown is the aft part of the electric motor 1 1 , in particular the rotor 1 10, stator 1 1 1 , and rear rotor bearings 113 which are sealed with respect to the interior hollow defined by the tubular drilling robot 1 .

[0184] Adjacent to the electric motor 1 1 in the rearward direction is the traction unit 12. The traction unit 12 comprises a bracing mechanism. The bracing mechanism is designed to brace the tubular drilling robot 1 against the drill bore 200 and / or the drill core 201 . The bracing mechanism may include one or more engagement members 120. The engagement members 120 are designed such that they can protrude from the tubular drilling robot 1 , i.e. extend beyond an exterior and / or interior overall enveloping shape, in particular extend to reach a maximal radial extension greater than the ring drill bit 10 and / or a extend inwards to a minimal radial extension from the centerline C less than the ring drill bit 10. By protruding, the engagement member 120 mechanically engage with the drill bore 200 and / or the drill core 201 during drilling, i.e. they can grip onto and / or partially dig into the rock such as to hold the tubular drilling robot 1 . In particular, this prevents the tubular drilling robot 1 counter-rotating when torque is applied to the ring drill bit 10 by the electric motor 1 1 and it props the traction force induced by the traction unit 12 onto the drill bore 200. The engagement members 120 are configured such that they can be extended and withdrawn, thereby engaging with the drill bore 200 and / or drill core 201 during drilling and disengaging with the drill bore 200 and / or drill core 201 when moving the tubular drilling robot 1 into and / or out of the drill bore 200.

[0185] The traction unit 12 is preferably designed to produce a radially balanced traction force, i.e. that the opposing forces are balanced on a centerline C of the tubular drilling robot 1 . This may be achieved by an even distribution of a plurality of engagement members

[0186] 120 around the tubular drilling robot 1 .

[0187] The engagement members 120 may be implemented using pawls, hooks, grips, etc. One embodiment is shown in which the engagement members 120 each comprise a pawl

[0188] 121 mounted on a pawl arm 122. The pawls 121 , which may include a biasing member, are designed to engage with the drill bore 200 and / or drill core 201 when the pawl arm

[0189] 122 is moved towards the aft of the tubular drilling robot 1 , i.e. in the negative z-direction. This occurs, in effect, by the pawls 121 being jammed and / or anchored against the rock.

[0190] The pawl arm 122 is designed to be moved from a fore position, where it slots into a recess 123 of the tubular drilling robot 1 and the pawl is pushed into a stowed position due to the recess (as shown in Figure 8), to an aft position in negative z-direction from the fore position (as shown in Figure 9). Once the pawl arm 122 leaves the recess 123, the pawl 121 moves from its stowed position due to the biasing action of the biasing member (e.g., a spring), into its deployed position where it engages with the rock. The pawl arm 122 is moved, for example by having grooves 124 which engages with a tubular screw 125. The tubular screw 125, by rotating, moves the pawl arm 122. By moving the pawl arm 122 and thereby engaging or disengaging the pawl 121 , the traction unit 12 can apply or remove the holding force, respectively. A plurality of pawl arms 122 may be driven by the tubular screw 125. The pawl arms 122 may be distributed about the tubular drilling robot, in particular about the traction unit 12, preferably evenly distributed. The pawl arms 122 may have different lengths.

[0191] In an embodiment, each pawl arm 122 may comprise a plurality of pawls 121 . The pawls 121 of a particular pawl arm 122, or the pawls 121 in general, may have differing lengths. Thereby, slight variations in the diameter of the drill bore 200 and / or the drill core 201 (for example, due to wear of the ring drill bit 10), can be compensated for, as the differing pawl lengths are designed to engage best with drill bores 200 and / or drill cores 201 of differing diameters.

[0192] The lateral holding force, in particular the sum of the lateral holding forces, may be in the range of several hundred kilo Newtons, .e.g., approximately 300 kN.

[0193] Additionally, as is described below, the traction unit 12 can also be configured to provide an advancing force, i.e. the force required for drilling. Alternatively or additionally, a separate advancing unit may provide or contribute to the advancing force.

[0194] In an embodiment, the advancing force is provided, at least in part, by the traction unit 12. In particular, the advancing force is provided by the tubular screw 125 which, once the pawls 121 are engaged with the drill bore 200 and / or the drill core 201 , continues to turn, thereby pushing the tubular drill robot 1 further into the drill bore 200, ensuring contact between the ring drill bit 10 and the rock of sufficient force or pressure to enable effective drilling.

[0195] The tubular screw 125, which is part of the tubular drilling robot 1 , may be arranged on either lateral side of the pawl arm 122, i.e. in front of or behind the pawl arm 122 in the z-direction. The tubular screw 125 is preferably designed with screw threads facing an interior of the tubular drilling robot 1 , i.e. the space between an exterior cylindrical shell of the tubular drilling robot 1 and an interior cylindrical shell of the tubular drilling robot 1 . A side of the tubular screw 125 opposite to the screw thread may form part of the cylindrical shell. For example, as shown in Fig. 6, the tubular screw 125 forms part of the inner cylindrical shell, the screw thread facing the interior of the tubular drilling robot 1 .

[0196] The tubular drilling robot 1 comprises, adjacent to the tubular screw 125, in particular in a cylindrical shell element of the cylindrical shell, interior or exterior cabling running in the axial direction for providing power to the electric motor 1 1 and transferring sensor signals.

[0197] Figure 7 shows a section view of a rear part a tubular drilling robot 1 , in particular section P shown in Figure 5. Shown is the rear part of the tubular screw 125 and an electric traction motor 126. These parts may be considered to implement the traction unit as described herein, in particular the advancing unit. More specifically, the advancing engine as described herein may be implemented by the electric traction motor 126.

[0198] The tubular screw 125 is driven by an electric traction motor 126. The electric traction motor 126 has an overall tubular shape, comprising a tubular traction motor rotor 127 and a tubular traction motor stator 128, which are preferably of the same design as the electric motor 11 described herein as connected to the ring drill bit 10. In particular, the tubular traction motor stator 128 includes hairpin windings, preferably continuous hairpin windings.

[0199] The electric traction motor 126 is designed as an interior rotor motor, in which the rotor 127 is rotatably arranged on bearings 129, 130 with respect to the stator 128. The rotor 127 may form part of the interior cylindrical shell of the tubular drilling robot 1 , in particular the electric traction motor 126. The stator 128 may form part of the exterior cylindrical shell of the tubular drilling robot 1 , in particular the electric traction motor 126.

[0200] The tubular screw 125 is interconnected with the electric traction motor 126, in particular the tubular traction motor rotor 127.

[0201] The fore bearings 129 may be implemented as a pair of angular contact bearings arranged in an X formation (face to face). The aft bearings 130 may be implemented as standard contact bearings.

[0202] Figure 8 shows a section view of part of the tubular drilling robot 1 , in which the pawls 121 of the traction unit 12 are in a recessed (fore) position. With the pawls 121 in this position, the traction unit 12 does not hold the tubular drilling robot 1 against the drill bore 200 and the tubular drilling robot 1 may be moved, for example pulled using a cable, through the drill bore 200.

[0203] Figure 9 shows a section view of part of the tubular drilling robot 1 , in which the pawls 121 of the traction unit 12 are in an engaged (aft) position. With the pawls 121 in this position, the pawls 121 are engaged against the drill bore 200 and the traction unit 12 thereby holds the tubular drilling robot 1 against the drill bore 200. Thereby, the drilling torque is matched and the tubular drilling robot 1 does not counter rotate during drilling. Additionally, by action of the tubular screw 125, the pawl arm 122 may be moved, thereby moving the tubular drilling robot 1 forwards or backwards inside the drill bore 200. Specifically, through action (rotation) of the tubular screw 125, an advancing force in the positive z-direction may be applied to the ring drill bit 10 of the tubular drilling robot 1 , facilitating drilling.

[0204] Figure 10 shows a perspective view of a tubular drilling robot 1 , including a cut-out section, details of which are shown in the section views of Figures 11 , 12, 13. The latter Figures show how the engagement members 120 of the traction unit 12, specifically the pawls 121 and the pawl arms 122, are moved from a fore position (as shown in Fig. 1 1 ) via an intermediary position (as shown in Fig. 12) to an aft position (as shown in Fig. 13).

[0205] After the pawl arms 122 have been moved from the fore position to the aft position (or to an intermediary position), they may be reset by moving them back to the fore position. Because the pawls 121 do not engage with the drill core 201 when moving back to the fore position, but rather slide along the drill core 201 , almost no force is applied onto the drill core 201 and therefore the tubular drilling robot 1 does not move. By repeatedly moving through the above described positions, the tubular drilling robot 1 may sequentially creep forward, however there is always a certain time during when the tubular drilling robot 1 does not move, because the pawls 121 are being reset.

[0206] Figures 14, 15, 16 illustrate how the pawls 121 , which may include a biasing member (illustrated as a spring), engage with the drill bore 200, through catching on the drill bore 200 and then jamming against it (and optionally also partially embedding into it), when moved towards the aft position (in the negative z-direction). The arrows indicate the forces present on the pawls 121 and consequently also the pawl arms 122. In particular, the engagement of the pawls 121 with the drill bore 200 provides a holding force H which ensures that the tubular drilling robot 1 is centered in the drill bore 20. Once the pawls 121 are fully engaged against the drill bore (as shown in Figure 16), the holding force H is maximized. Also shown is the reaction force R generated by the traction motor 126 which provides an equal and opposite advancing force.

[0207] The tubular drilling robot 1 , in an embodiment, includes two traction units 12 arranged in sequence along the z-direction (not shown). The traction units 12 are configured such that the first traction unit 12 resets itself into the fore position while the second traction unit 12 is moving the engagement elements 120 from the fore position to the aft position. As the reset movement can be done faster than the drilling movement, the two sequences can overlap for a short time, transferring smoothly the traction force from one unit to the other. Thereby, a near constant advancing force is present and the tubular drilling robot 1 drills almost uninterruptedly.

[0208] Figures 17 - 21 show section views of a tubular drilling robot 1 inside a drill bore 200 in various states. In particular, the tubular drilling robot 1 includes a ring drill bit 10 which features movable diamond supports 106, in particular slidable diamond supports 106, such that the effective inner and / or outer radius of the ring drill bit 10, in other words, the inner and outer gauge radius, or the size of the drill bore 200 and / or the size of the drill core 201 , is variable.

[0209] This is advantageous because the drill bore 200 does not have a precisely consistent radius. Neither does the drill core 201 . The inconsistent radii are due to wear of the ring drill bit 10, which, as drilling proceeds, wears. Therefore, the ring drill bit 10, in particular the outer gauge (corresponding to the drill bore 200 diameter) decreases, while the inner gauge (corresponding to the drill core diameter) increases. This is shown in an exaggerated manner in the above-mentioned figures. In fact, the drill bore radius only decreases by about a millimeter or less and the drill core radius also only increases by about the same amount. This small change can, however, lead to jamming of the ring drill bit 10 in prior art drill bits, after the ring drill bit 10 and / or the tubular drilling robot 1 is repaired or replaced. In other words, once the ring drill bit 10 of the tubular drilling robot 1 has worn to the point where it must be repaired or replaced, the tubular drilling robot 1 is pulled out of the drill bore 200. The tubular drilling robot 1 with a repair or replaced ring drill bit 10, or a new tubular drilling robot 1 cannot reach the end of the drill bore 200 again as the narrowing drill bore 200 diameter is smaller than the ring drill bit diameter. As a result, prior art drill bits often have to re-drill their way to the bottom of the drill bore 200, thereby wearing the diamonds 1010 and increasing drilling times. The disclosed ring drill bit 10 with a variable inner and / or outer radius overcomes this disadvantage and allows a tubular drilling robot 1 with a fresh ring drill bit 10 to be moved to the end of the drill bore 200 without jamming.

[0210] The disclosed ring drill bit 10 with a variable inner and / or outer radius is configured such that, at the beginning of the new drilling sequence, the ring drill bit 10 expands laterally into a cutting configuration. The lateral expansion can include an outer expansion, which increases the radius of the drill bore 200 and / or an inner expansion, which decreases the radius of the drill core 201. As a consequence, the size of the drilled drill bore 200 and / or drill core 201 provides more room for the ring drill bit 10 when the ring drill bit 10 is not drilling. Thereby, a new or repaired ring drill bit 10 can proceed through the drill bore 200 without jamming and without having to re-drill the drill bore 200 (in particular to increase its gauge slightly). When not drilling, the ring drill bit 10 may move, passively or actively, into a clearance configuration.

[0211] The ring drill bit 10 may move from the clearance configuration to the cutting configuration by use of a radial adaptation mechanism 107, which may be part of the ring drill bit 10. The radial adaptation mechanism may include a biasing member, such as a spring, and / or an actively driven member.

[0212] The ring drill bit 10 may be configured such that the inner and / or outer radius of the ring drill bit 10 increases, for example by way of the radial adaptation mechanism 107, when an advancing force is applied, in particular an advancing force applied by the tubular drilling robot 1 on the ring drill bit 1.

[0213] In an embodiment, the ring drill bit 10 comprises a plurality of diamond supports 106. Each diamond support 106 preferably holds, or otherwise has attached thereto, a number of diamonds 1010. The diamond supports 106 and / or the ring drill bit 10 includes a radial adaptation mechanism 107 designed such that diamond supports 106 are movably attached to the ring drill bit 10. In other words, the diamond supports 106 can move relative to the ring drill bit 10. Specifically, the radial adaptation mechanism 107 is configured such that the outer gauge and / or inner gauge of the ring drill bit 10 can be increased and / or decreased. The plurality of diamond supports 106 may be arranged circumferentially around the ring drill bit 10, such that the diamonds 1010 are exposed on at least one of the cutting faces 101 , preferably the front cutting face 101 A, the outer gauge cutting face 101 B, and the inner gauge cutting face 101 C.

[0214] In an embodiment, the ring drill bit 10 comprises two types of diamond supports 106A, 106B. A first type diamond support 106A comprises diamonds 1010 on the outer gauge cutting face 101 B of the ring drill bit 10, and is configured to move radially outwards during drilling, thereby increasing the outer gauge, i.e. increasing the size of the drill bore 200. A second type diamond support 106B comprises diamonds 1010 on the inner gauge cutting face 101 C and is configured to move radially inwards during drilling, thereby decreasing the inner gauge, i.e. reducing the size of the drill core 201 .

[0215] The first and / or second type of diamond support 106A, 106B may comprise diamonds 1010 on the front cutting face 101 A.

[0216] Preferably, the first and second type of diamond supports 106A, 106B are arranged al- ternatingly around the ring drill bit 10.

[0217] The radial adaptation mechanism 107 may include a carriage 108 arranged on the diamond support 106, the carriage 108 being slidably arranged in a guiding slide 109 of the ring drill bit 10. The guiding slide 109 is arranged inclined with respect to the axial direction of the ring drill bit 10, i.e. angled with respect to the drilling direction, in particular forming an acute angle of 25-45 degrees to the axial (+z) direction. Thereby, the radial adaptation mechanism 107 enables the adaptation of the radial position of the cutting portion from the clearance configuration 180 to the cutting configuration 181 when the advancing force is applied during drilling.

[0218] Figure 17 shows the ring drill bit 10 of the tubular drilling robot 1 in a cutting configuration 181 at the bottom of the drill bore 200. The drill core 201 is not shown for sake of clarity. The outer contour of the drill bore 200 is shown having a varying radius, which radius narrows as the ring drill bit 10 wears. Once the ring drill bit 10 is worn (i.e., the diamonds are worn), as shown in Figure 17, the ring drill bit 10 must be replaced or repaired.

[0219] A fresh ring drill bit 10 is then inserted into the drill bore 200 as depicted in Figure 18. The ring drill bit 10 is in the clearance configuration 180 and can therefore be freely moved or lowered into position at the bottom of the drill bore 200.

[0220] In Figure 19, the ring drill bit 10 has reached the bottom of the drill bore 200 and is once again in the cutting configuration. Figures 20 and 21 show further stages of drilling, the ring drill bit 10 being in cutting configuration 181 in both.

[0221] Figures 22 to 28 show schematically diamond supports 106 in various configurations. These figures are intended to show exemplary arrangements of the diamonds 1010 on the diamond supports 106, in particular how rows of diamonds 1010 may be arranged relative to each other on one or more diamond supports 106. For the sake of clearly illustrating these arrangements, only one or two diamond supports 106 are shown in each figure, these diamond supports 106 arranged such as to form part of the front cutting face 101 A, however, these or other diamond supports 106 may additionally or alternatively include diamonds 1010 on other cutting faces 101 B, 101 C. The diamonds 1010 may be fixed onto and / or into the diamond support 106 by a diamond setting. Alternatively or additionally, the diamonds 1010 may be fixed onto and / or into the diamond support 106 by way of a solder, in particular an active soldering material 1011.

[0222] The active soldering material is preferably a silver-copper alloy with titanium. The diamonds are soldered to the diamond support 106 or the ring drill bit 10 in a high vacuum at more than 900 °C.

[0223] If single crystal diamonds with the well-defined octahedral shape are used, the diamond support 106 (as shown in Figures 22-25) has preferably cavities of an at least partly negative octahedral shape with angles corresponding those of the diamonds. This gives a best fit for the diamonds 1010 which can be fixed by a uniform and thin solder layer. The diamond supports 106 with the octahedral shape cavities are preferably fabricated by 3D printing (e.g. stainless steel) or by investment casting.

[0224] Figures 22 and 23 show a diamond support 106 including a single row of six octahedral single crystal diamonds 1010 arranged on the front cutting face 101 A, extending across the width of the front of the ring drill bit 10. Figure 22 shows new diamonds, whereas Figure 23 shows worn diamonds. The octahedral single crystal diamonds 1010 are all oriented such that an edge of the octahedral single crystal diamonds 1010 points in radial direction (i.e. in the positive x-direction). Thereby, another edge of the diamonds 1010 points in circumferential direction (i.e. in the y-direction), being also the direction of rotation. This provides for optimal cutting of rock while drilling. A plurality of such diamond supports 106 may be arranged around the ring drill bit 10.

[0225] Some embodiments of the ring drill bit 10 described herein use octahedral single crystal diamonds 1010, preferably of a large size of between 0.5 mm - 1 .5 mm. Octahedral single crystal diamonds 1010 have the advantage that they are larger than typical diamonds embedded in known drill bits. This means they last longer and that they provide for more space between diamonds and between a tip of a diamond and other parts of the ring drill bit 10, such as the diamond support 106, the magazine 1061 or the base section 103 of the ring drill bit 10. This allows for the drilling fluid to more easily penetrate between the diamonds and flush out silt produced during drilling.

[0226] Figure 24 shows a similar arrangement as Figure 22, with the addition of a second diamond support 106 adjacent to the first. The diamonds 1010 on the second diamond support 106 are arranged in a row parallel to the row of diamonds 1010 on the first diamond support 106, however laterally displaced by half the width of a diamond 1010, such that each diamond 1010 on the second diamond support 106 falls in a gap between two adjacent diamonds on the first diamond support 106. Thereby, the cutting is improved. Preferably, a plurality of first and second diamond supports 106 are alternating^ arranged around the ring drill bit 10.

[0227] Figure 25 shows a side on section view of two diamond supports, one behind the other staggered in height by about a quarter of the diamond size. Thereby, the diamonds 1010 on the second diamond support 106 only engage with the rock once the diamonds 1010 on the first diamond support 106 have worn or are broken. This results in fresh and sharp diamonds 1010 being used for drilling once the diamonds 1010 on the first diamond support 106 have worn and provides for a more longer lifespan of the ring drill bit 10.

[0228] In an embodiment, three or more diamond supports 106 of differing vertical displacements are arranged next to each other.

[0229] Preferably, repeated sequences of diamond supports 106 of differing vertical displacements are arranged around the ring drill bit 10. Figure 26 shows a side section view of at least part of a diamond support 106. The diamond support 106 includes a magazine 1061 , which at least partially houses a plurality of columns of diamonds 1010. The column of diamonds 1010 extend in the z-direc- tion. The magazine 1061 may be open at the top (in the positive z-direction) and preferably, at least one diamond 1010 protrudes beyond the magazine 1061 and / or the diamond support 106. In the figure, three columns are shown, however more or less are also possible. The columns typically include in the range of 2 - 10 diamonds 1010.

[0230] Depending on the embodiment, the total number of diamonds extending across the radial width of the ring drill bit 10 is in a range of 5 to 30, preferably from 10 to 20. The number of diamonds in row in a particular magazine 1061 is typically in the range of 2 - 10, depending on the particular row.

[0231] The diamond support 106 is arranged on the ring drill bit 10 such that it extends or protrudes above the base section 103 of the ring drill bit 10. The diamond support 106 may extend partially or fully above the ring drill bit 10, i.e. such that the column of diamonds 1010 are all arranged in a z-position beyond the base section 103 of the ring drill bit 10.

[0232] The magazine 1061 includes a structural frame of one or more walls. The walls define one or more recesses which are designed such that at least one column of diamonds 1010 fits inside. The diamonds 1010 are preferably stacked end-on-end in the column. The space between the diamonds 1010 is filled with active soldering material 101 1 , which also holds the diamonds 1010 in place.

[0233] During drilling, the top diamond 1010A gradually becomes worn, damaged, chipped or lost. The rotating action of the ring drill bit 10 against the rock causes the active soldering material 1011 to wear away, resulting in a subsequent diamond 1010B being exposed to the rock to continue the cutting action. Using magazines 1061 as in Figures 26-28 in other embodiments single crystal diamonds of similar sizes of more irregular than octahedral shape may be used. These diamonds are significantly cheaper und do not have shock sensitive pikes. Also the filling factor (volume of diamonds 1010 in a magazine 1061 ) may be higher.

[0234] Figure 27 shows a top view of the magazine 1061 as shown in Figure 26.

[0235] Figure 28 shows a section view of a magazine in which three columns of diamonds 1010 are arranged without any separating walls. The middle column is vertically shifted with respect to the outer columns such that the diamonds 1010 of the middle column lie between the diamonds 1010 of the outer columns. Thereby, the more consistent cutting performance is achieved as the diamonds wear.

[0236] As in Figures 26 and 27 it may be preferable to use single crystal diamonds of similar sizes having a more irregular shape than octahedral diamonds because of the price, the shock resistivity and the filling factor of the latter diamonds.

[0237] Figures 29 to 32 show perspective views of a ring drill bit 10 and parts thereof, in particular including a plurality of diamond supports 106, 106A, 106B arranged around the ring drill bit 10 featuring magazines 1061 configured to hold diamonds 1010 (not shown).

[0238] The diamond supports 106, 106A, 106B may be arranged at an angle to a radial direction, in particular an angle of up to 45 degrees.

[0239] Figure 29 shows a ring drill bit 10 designed to be used with a tubular drill robot 1 as described herein. The ring drill bit 10 has an overall annular shape. The ring drill bit 10 has a front cutting face 101 A. The cross section of the ring drill bit 10 tapers back from the front cutting face 101 A, which is the widest part of the ring drill bit 10, towards the back of the ring drill bit 10 (i.e. in the negative z-direction). The taper may include a taper of the inside and / or the outside of the ring drill bit 10.

[0240] The ring drill bit 10 also has an outer gauge cutting face 101 B and an inner gauge cutting face 101 C.

[0241] The ring drill bit 10 comprises a base section 103, preferably made of metal. Attached to the base section 103 are a plurality of diamond supports 106, which are shown in more detail in the following figures.

[0242] The base section 103 may include a plurality of bolt holes 1012 which extend, from the front face 101 A, in negative z-direction through the base section 103. The bolt holes 1012 are designed to receive bolts for attaching the ring drill bit 10 to another component of the tubular drilling robot 1 , in particular the electric motor 11 (not shown). The bolt holes 1012 are thereby considered part of the drill bit coupling mechanism 104.

[0243] A plurality of diamond supports 106 are movably attached to the base section 103. Specifically, the diamond supports 106 include a carriage 108 as shown in Figs. 31 and 32 in more detail, which carriage 108 is designed to slide on a guiding slide 109 of the base section 103.

[0244] The guiding slide 109 is implemented in or as a recess in the base section 103 having a substantially cylindrical shape (e.g., circular cylindrical), and may include guide elements such that the carriage 108 may slide freely through a particular range of motion inside the guiding slide 109.

[0245] The carriage 108 and guiding slide 109 define a sliding axis which forms an angle with the z-direction (i.e. the axial direction of the ring drill bit 10) of between 25 and 45 degrees. Thereby, when the carriage 108 moves along the guiding slide 109, the diamond support 106 connected to the carriage 108 not only moves in the z-direction, but also radially outwards or inwards (i.e. in the x-y plane). The guiding slide 109 may include a biasing member, for example a spring configured to provide an extension force on the carriage 108 such that the carriage 108 is pushed in the positive z-direction. The biasing member is configured such that the advancing force during drilling readily overcomes the extension force, thereby pushing the carriage 108 back into the guiding slide 109 .

[0246] A first type of diamond support 106A has a carriage 108 which is angled towards the axis of the ring drill bit 10 in forward direction (positive z-direction), mounted in a guiding slide 109 of the base section 103 which is oriented similarly (as shown also in Figs. 17 to 21 ). Thereby, a movement in negative z-direction (in particular against a biasing member), which movement may be caused during drilling due to the advancing force, also causes the diamond support 106A to move radially outwards, thereby increasing the outer gauge radius of the ring drill bit 10. In such a manner, the first diamond support 106A drills the drill bore 200 with radius such that, once the advancing force is removed, the first diamond support 106A moves radially inwards and consequently the ring drill bit 10 as a whole has a smaller outer radius than the drill bore 200 such that the ring drill bit 10 may be removed from the drill bore 200 without issue. Likewise, a new or repaired ring drill bit 10 may enter the drill bore 200 without jamming on the narrowing drill bore 200 because the first diamond support 106A is radially withdrawn. Only once the advancing force is reapplied does the first diamond support 106A get effectively pushed outwards.

[0247] A second type of diamond support 106B has a carriage 108 which is angled away from the axis of the ring drill bit 10 in forward direction, mounted in a guiding slide 109 of the base section 103 which is oriented in the same direction. Thereby, a movement in negative z-direction (in particular against a biasing member), which movement may be caused during drilling due to the advancing force, also causes the diamond support 106B to move radially inwards, thereby decreasing the inner gauge radius of the ring drill bit 10. In such a manner, the second diamond support 106B drills the drill core 201 with a radius such that, once the advancing force is removed, the second diamond support 106B moves radially outwards and consequently the ring drill bit 10 as a whole has a larger inner radius than the drill core 201 such that the ring drill bit 10 may be removed from around the drill core 201 without issue. Likewise, a new or repaired ring drill bit 10 may enter around a pre-existing drill core 201 without jamming on the widening drill core 201 because the second diamond support 106B is radially extended. Only once the advancing force is reapplied does the second diamond support 106B get effectively pushed inwards.

[0248] Figure 30 shows a cross-sectional perspective view of the ring drill bit 10 in the cutting configuration, in particular a first diamond support 106A. The first diamond support 106A includes, in an upper part, a magazine 1061 comprising a number of adjacent vertically oriented wells (i.e., oriented in the z-direction) separated by walls. The magazine 1061 is designed such that each well may receive a plurality of stacked diamonds 1010 held in place by an active soldering material 1011 , as described above with reference to Figures 26 to 28 in more detail.

[0249] The magazine 1061 is designed such that, during drilling, it may be worn away, thereby exposing successive diamonds 1010 of each well which may be used successively for cutting. Thereby, the magazine 1061 enables a long drilling lifespan of the ring drill bit 10.

[0250] The first diamond support 106A, as shown in Figure 31 , is designed to at least partly provide the front cutting face 101 A and the outer gauge cutting face 101 B of the ring drill bit 10. The second diamond support 106B, as shown in Figure 32, is also designed to at least partly provide the first cutting face 101 A and the inner gauge cutting face 101 C. The ring drill bit 10 is preferably designed such that the diamond supports 106, 106A, 106B may be replaced once the diamonds 1010 are used up or worn out, i.e. the diamond supports 106, 106A, 106B may be removed from the ring drill bit 10 and replaced with new diamond supports 106, 106A, 106B.

[0251] The magazine 1061 of the first diamond support 106A includes a first row of wells extending in radial direction which is designed such that, when the first diamond support 106A is attached to the ring drill bit 10, at least one of the wells extends beyond the outer edge of the ring drill bit 10, specifically the outer edge of the base section 103. Further rows of wells may be arranged adjacent to the first row, preferably with an offset. The further rows of wells do not necessarily have the same length as the first, but may be arranged near the outer edge of the ring drill bit 10. For example, the magazine 1061 includes two adjacent rows of wells, in particular one row either side of the first row. The adjacent rows of wells include 2 - 6 wells each and abut with the outer edge (in radial direction) of the first row of wells.

[0252] The depth of the wells may vary, in particular, the depth of those wells extending beyond the outer edge of the base section 103 of the ring drill bit 10 may be deeper than the depth of those wells situated between the inner and outer edge of the base section 103. Thereby, the wells extending beyond the outer edge of the base section 103 may receive more diamonds 1010 than the other wells.

[0253] Those wells extending beyond the outer edge of the base section 103 may include diamonds 1010 which form or provide, at least partly, the outer gauge cutting face 101 B. In particular, as the well walls may be worn during drilling, the diamonds 1010 arranged in the outer wells define, at least partly, the outer gauge cutting face 101 B. The first row of wells does not necessarily extend completely between the inner and outer edge of the base section 103.

[0254] The magazine 1061 shows wells which are co-parallel to each other in the z-direction. However, the magazine 1061 may additionally or alternatively also include wells which are not aligned with the z-direction, but form an angle with the z-direction of up to 90 degrees. In particular, the first diamond support 106A may include wells which are angled outwards from the z-direction in radial direction at 45 degrees, such as to improve the cutting of the outer gauge of the drill core 201 .

[0255] The magazine 1061 of the diamond support 106A is designed such that it is arranged on top of the ring drill bit 10 (in z-direction) when the diamond support 106A is installed.

[0256] The considerations and details described above with reference to the magazine 1061 of the first diamond support 106A apply analogously to the magazine 1061 of the second diamond support 106B, taking into account that the second diamond support 106B is designed to move inwards, i.e. towards the axis of the ring drill bit 10, when drilling.

[0257] As can be seen, particularly in Fig. 32, a plurality of rows of wells terminate at the inner edge of the magazine 1061 of the second diamond support 106B. In an embodiment, the magazine 1061 comprises at least one well angled towards the axis, thereby providing improved cutting of the inner gauge (i.e. cutting of the drill core 201 ).

[0258] Figure 33 shows a highly schematic diagram illustrating a tubular drilling robot 1 inside a drill bore 200. The tubular drilling robot 1 is at the bottom end of the drill bore 20 inside a geological formation G in the earth E, the geological formation G comprising one or more types of rock. The tubular drilling robot 1 comprises a ring drill bit 10 which removes the rock in a ring-shaped area, thereby drilling the drill bore 200 and leaving behind a drill core 201 , which drill core 201 is circular cylindrical and extends at least partly through the tubular drilling robot 1 . The drill bore 200 has a surface 202, which may be considered to include an outer surface as well as an inner surface next to the drill core 201 .

[0259] A separate and external remote control station 14 is situated remote from the tubular drilling robot 1 , preferably on the Earth’s surface in the vicinity of the drill bore 200. The tubular drilling robot 1 is connected to the remote control station 14 by cabling 141.

[0260] The cabling 141 comprises electrical cabling configured to provide electrical power to the tubular drilling robot 1 . The electrical power is preferably provided in the form of high voltage low frequency AC, preferably DC power.

[0261] The cabling 141 may further comprise signal cabling configured to provide control signals and / or receive sensor signals from the tubular drilling robot 1 . The tubular drilling robot 1 may comprise a control unit configured to receive the control signals and perform accordingly.

[0262] The cabling 141 may further comprise tubing to transport drilling fluid to the tubular drilling robot 1 and / or to remove drilling fluid from the drill bore 200.

[0263] The cabling 141 is preferably designed such that the tubular drilling robot 1 may be pulled out of the drill bore 200, for example for repair and / or replacement. In particular, the ring drill bit 10, in particular the diamonds 1010 the diamond support 106 and / or the magazine 1061 may wear and be replaced.

[0264] The drill core 201 is shown extending above the tubular drilling robot 1 .

[0265] The tubular drilling robot 1 is preferably configured to break, snap, saw, twist or otherwise separate the drill core 201 either into one or more segments and / or detach it from the rock R below the tubular drilling robot 1. A drill core removal mechanism 142, which is, in an embodiment, considered part of the tubular drilling robot 1 , comprises an attachment mechanism which attaches to at least a segment of the drill core 201 . The segment of the drill core 201 may then be removed from the drill bore 200, for example by a drill core removal cabling 143 attached to a winching mechanism arranged in the remote control station 14.

[0266] Preferably, the winching mechanism is attached to the bottom of the drill core 201 , thereby lifting the core “by the foot” instead of “by the head”. This can avoid ruptures caused by defects in the structure of the rock. This embodiment is not shown for sake of clarity.

[0267] Figure 34 shows a section view of a tubular drilling robot 1 with fresh drilling fluid 203 directed to the inside of the tubular drilling robot 1 . The slide seal ring 205 avoids leaks of the fresh drilling fluid 203 directly upwards past the tubular drilling robot 1 . The fresh drilling fluid 203 is then forced to pass through or past the ring drill bit 10, where it removes the drill cuttings away from the cutting members and becomes used drilling fluid 204, i.e. a mixture of fresh drilling fluid and drill cuttings. The used drilling fluid 204 containing the drill cuttings moves then between the outer surface of the tubular drilling robot 1 and the drill bore 200 upwards as indicated by the arrows.

[0268] Figure 35 shows a section view of a tubular drilling robot 1 with a closed prolongation tube 206 tightly connected to the tubular drilling robot 1 . The prolongation tube 206 has a tubular shape with a diameter corresponding to the diameter of the tubular drilling robot 1 . The prolongation tube 206 is closed at a top end. The tube 206 must be longer than the maximum length of the drill core 201. The fresh drilling fluid 203 is fed by a cabling system 141 into the closed prolongation tube 206. As in Figure 34, the fresh drilling fluid 203 is forced to flow in drilling direction past the inside surface of the tubular drilling robot 1 and pass by the ring drill bit 10. The prolongation tube 206 acts also as transportation shell when the drill core 201 is lifted up to the Earth’s surface.

[0269] Figure 36 shows a highly schematic diagram illustrating a tubular drilling robot 1 inside a drill bore 200, similar to Figure 33. Some features shown in Figure 33 are omitted to improve clarity. An airstream transport system 15 is shown which includes a nozzle system 151 , airstream tubing 152, and an airstream pump 153, which may be implemented as an air compressor.

[0270] The airstream pump 153 is configured to pump compressed air down the tubing 152 and into the drill bore 200 through the nozzle system 151. The nozzle system 151 may include a plurality of two component jet nozzles. The used drilling fluid 204 flows through a central conduit of the two component jet nozzles, atomizing and mixing with an enveloping high speed flow of the airstream. The high flow rate and high speed airstream, having the fine water droplets and abrasives particles dispersed, lifts the used drilling fluid 204, together with the mixed drill cuttings, out of the drill bore 200, thereby reducing the hydrostatic pressure on the tubular drilling robot 1 .

[0271] The used drilling fluid 204 (a water and abrasives mixture) fills the drill bore 200 to a height of between 1 m and 100 m above the top of the drill core 201 . The nozzle system 151 is arranged within this column of water, preferably at a depth near the top of the column, creating a powerful vortex of dispersed drilling fluid in the compressed air, forcing the dispersed used drilling fluid 203 out of the drill bore 200 and up to the Earth’s surface.

[0272] Figure 37 shows a flow diagram illustrating a method including a number of exemplary steps S1 -S4 for drilling a drill bore, in particular through rock, using a tubular drilling robot 1 . The method may be performed for drilling, at least partly, a drill bore into the Earth E, in particular for drilling through rock R. The method may be augmented with preliminary or subsequent steps, which may include using known conventional techniques for drilling through soil or other softer substrates which do not necessarily require a ring drill bit as described herein.

[0273] In step S1 , a tubular drilling robot as described herein is provided. The tubular drilling robot 1 may be lowered into a pre-existing drill bore 200, or the tubular drilling robot 1 may arranged on the Earth’s surface.

[0274] In step S2, the drill bore 200 is drilled using the tubular drilling robot 1. In particular, the tubular drilling robot 1 may be powered via the cabling 141 such that it drills and such that the traction unit operates as described herein to hold the tubular drilling robot 1 in place during drilling and / or to provide an advancing force for improved drilling. The cabling 141 may further provide control signals to a control unit of the tubular drilling robot 1 designed to control the drilling and / or other functions of the tubular drilling robot 1 .

[0275] Once the ring drill bit 10 of the tubular drilling robot 1 requires repair or replacement, the tubular drilling robot 1 may be removed from the drill bore 200, repaired and / or replaced, and lowered into the drill bore 200.

[0276] In an optional step S3, the drill core 201 is at least partially removed. The drill core 201 may be segmented by the drill core removal mechanism 142 and / or by a drill core segmenting mechanism integrated into the tubular drilling robot 1 . Segments of the drill core 201 are removed from the drill bore 200, for example by being grasped and lifted out using drill core removal cabling 143.

[0277] In an optional step S4, the surface 202 of the drill bore 200 is sealed, such that it is watertight or near water-tight. Preferably, the drill bore 200 is sealed using drill cuttings produced from drilling the rock. However, it may not be necessary to seal the drill bore 200 in a separate step. The high speed diamond cutting provided by the described tubular drilling robot 1 and drilling method yields small particles, most of these being less than 0.3 mm in size. Many particles are as small as a few microns. These very small particles contribute to sealing the wellbore during the drilling process without additional measures by simply plugging the fissures in the surrounding rock, pressed into the cavities by the high pressure in the drilling fluid (204).

[0278] LIST OF REFERENCE SYMBOLS

[0279] I tubular drilling robot 113 rear rotor bearings

[0280] 10 ring drill bit 12 traction unit

[0281] 101 cutting face(s) 120 engagement members

[0282] 101 A front cutting face 30 121 pawls

[0283] 101 B outer gauge cutting face 122 pawl arms

[0284] 101C inner gauge cutting face 123 recess

[0285] 102 cutting face support 124 grooves

[0286] 103 base section 125 tubular screw

[0287] 104 drill bit coupling 35 126 electric traction motor

[0288] 106 diamond support 127 traction motor rotor

[0289] 106A first diamond support 128 traction motor stator

[0290] 106B second diamond support 129 traction motor fore bearings

[0291] 1061 magazine 1210 traction motor aft bearings

[0292] 107 radial adaptation mechanism 40 13 advancing unit

[0293] 108 carriage 14 remote control station

[0294] 109 guiding slide 141 cabling

[0295] 1010 diamond 142 drill core removal mechanism

[0296] 1010A top diamond 143 drill core removal cabling

[0297] 1010B subsequent diamond 45 15 airstream transport system

[0298] 1011 active soldering material 151 nozzle system

[0299] 1012 bolt holes 152 airstream tubing

[0300] I I electric motor 153 airstream pump

[0301] 110 rotor 180 clearance configuration

[0302] I I I stator 50 181 cutting configuration

[0303] 112 front rotor bearings 200 drill bore 201 drill core 206 closed prolongation tube

[0304] 202 surface of drill bore 210 drill direction

[0305] 203 fresh drilling fluid E Earth

[0306] 204 used drilling fluid G geological formation 205 slide seal ring

Claims

CLAIMS1 . A tubular drilling robot (1 ) for earth drilling, in particular for rock drilling, the drilling robot (100) comprising: a ring drill bit (10) having a hollow cylindrical shape and being configured for drilling, thereby producing a solid cylindrical drill core (201 ) and a tubular drill bore (200) during drilling; an electric motor (1 1 ) having a hollow cylindrical shape, being mechanically connected to the ring drill bit (10) and being configured to provide the rotational power for drilling; and a traction unit (12) mechanically connected with the electric motor (1 1 ) and configured to engage with at least one of: an inner surface of the tubular drill bore (200) or an outer surface of the drill core (201 ), and configured to hold and / or move the tubular drilling robot (1 ).

2. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the ring drill bit (10) has a hollow cylindrical shape throughout its entire length and provides an inner fully cylindrical cavity for receiving the solid-material fully cylindrical drill core (201 ).

3. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein an outer radius of the ring drill bit (10) defines an outer radius of the tubular drill bore (200), and / or an inner radius of the ring drill bit (10) defines an inner radius of the tubular drill bore (200).

4. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein an inner radius of the ring drill bit (10) defines an outer radius of the solid-material fully cylindrical drill core (201 ).

5. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the tubular drilling robot (1 ), in particular the electric motor (1 1 ), has a hollow cylindrical shape throughout its entire length, in particular wherein the hollow cylindrical shape of the tubular drilling robot (1 ) is matched in radial dimensions to the hollow cylindrical shape of the ring drill bit (10).

6. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the traction unit (12) includes a bracing mechanism comprising one or more engagement members configured to engage with the at least one of: the surface of the tubular drill bore (200) or the surface of the drill core (201 ), thereby providing a holding force which holds the tubular drilling robot (1 ) in place during drilling.

7. The tubular drilling robot (1 ) according to any of the preceding claims, wherein the traction unit (12) includes an advancing unit (13) configured to exert an advancing force on the ring drill bit (10) during drilling.

8. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the advancing unit (13) further comprises at least one advancing engine, which is configured to move the ring drill bit (10) axially along the drill bore (200) with respect to the bracing mechanism of the traction unit (12), in particular the engagement members (120) of the traction unit (12), for providing a quasi-continuous advancing force on the ring drill bit (10) during drilling of the drill bore (200).

9. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the traction unit (12) comprises at least two engagement members (120), which are configured to be independently engageable with one or more of: the surface (202) of the drill bore (200) or the surface of the drill core (201 ), and which engagement members are configured to be axially moveable with respect to the ring drill bit (10), wherein the first engagement member (120) is configured to engage, during an engagement period, with the surface (202) of the drill bore (200) and / or the surface of the drill core (201 ), during which engagement period the second engagement member (120) is not engaged with the surface (202) of the drill bore (200) or the surface of the drill core (201 ).

10. The tubular drilling robot (1 ) according to any one of the preceding claims, further comprising a plurality of weights, preferably having at least partially a tubular ring shape, which engage on the ring drill bit (10) thereby providing at least partially the advancing force.1 1 . The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the electric motor (1 1 ) is an ironless ring electric motor.

12. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the advancing engine comprises an ironless electric motor configured to drive a tubular screw (125).

13. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the radial outer extension of the ring drill bit (10) is the largest radial outer extension of the tubular drilling robot (1 ), and wherein the radial inner extension of the ring drill bit (10) is the smallest radial inner extension of the tubular drilling robot (1 ), such that the tubular drilling robot (1 ) is moveable in the drill bore (200), in particularwhen the traction unit (12) is unengaged with the surface (202) of the resulting drill bore (200).

14. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the ring drill bit (10) is configured to rotate with a rotational velocity at its radial inner end of at least 5 m / s, preferably at least 10 m / s.

15. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the ring drill bit (10) is configured to rotate at rotational speeds higher than 1000 rpm.

16. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the tubular drilling robot (1 ) is supplied with electrical power from a remote control station (14) arranged on the Earth’s surface via cabling (141 ) extending along the drill bore (200).

17. The tubular drilling robot (1 ) according to any one of the preceding claims, further comprising a control unit configured to control the tubular drilling robot (1 ), in particular at least one or more of: the electric motors (1 1 , 126) or the traction unit (12).

18. The tubular drilling robot (1 ) according to any one of the preceding claims, further comprising a drill core removal mechanism (142), which is configured to remove, in particular by breaking-off, after predefined intervals or continuously, at least segments of the drill core (201 ) during drilling.

19. The tubular drilling robot (1 ) according to claim 18, wherein the drill core removal mechanism (142) is further configured to transport the removed, in particular broken-off, segments of the drill core (201 ) at least partially out of the drill bore (200).

20. The tubular drilling robot (1 ) according to any one of the preceding claims, further comprising a guidance mechanism configured to control a drill direction (210) of the tubular drilling robot (1 ) during drilling.21 . The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the ring drill bit (10) comprises a plurality of diamonds (1010) arranged to cut rock material while drilling.

22. The tubular drilling robot (1 ) according to claim 21 , wherein the diamonds (1010) include directionally oriented single crystal octahedral diamonds (103).

23. The tubular drilling robot (1 ) according to any one of the claims 21 or 22, wherein the ring drill bit (10) includes at least one diamond support (106), each diamond support (106) configured to hold one or more of the diamonds (1010).

24. The tubular drilling robot (1 ) according to any one of the claims 21 or 23, wherein the diamonds (1010) are held preferably by an active soldering material (101 1 ) which fixes the diamonds (1010) in place.

25. The tubular drilling robot (1 ) according to claim 24, wherein the active soldering material (1011 ) comprises a combination of copper, silver and titanium, in particular 30% - 40% percent copper by weight, 60% - 70% percent silver by weight and 1 % - 5% percent titanium by weight.

26. The tubular drilling robot (1 ) according to one of claims 23 to 25, wherein each diamond support (106) comprises at least one magazine (1061 ) configured to house a sequence of diamonds (1010) such that, during drilling, once a particulardiamond (1010A) is at least partially worn, fractured, or lost, a subsequent diamond (101 OB) in the sequence is made available for drilling.

27. The tubular drilling robot (1 ) according to any one of the preceding claims, wherein the ring drill bit (10) comprises a radial adaptation mechanism (107), which is configured to adapt the radial position of at least one cutting portion of the ring drill bit (10), in particular of the diamond support (106), from a first clearance configuration (180) to a second cutting configuration (181 ), wherein the clearance configuration (180) enables a movement of the ring drill bit (10) along the drill bore (200).

28. The tubular drilling robot (1 ) according to claim 27, wherein the radial adaptation mechanism (107) includes a passive mechanism which is configured to move the ring drill bit (10) into the second cutting configuration (181 ) when an axial force in the advancing direction is applied.

29. The tubular drilling robot (1 ) according to one of claims 27 or 28, wherein the radial adaptation mechanism (107) may include a carriage (108) which includes the cutting portion, the carriage (108) being slidably arranged in a guiding slide (109) of the ring drill bit (10), wherein the guiding slide (109) is arranged inclined with respect to the axial direction of the ring drill bit (101 ), thereby enabling to adapt the radial position of the cutting portion from the clearance configuration (180) to the cutting configuration (181 ).

30. A drilling system for drilling bore holes into the Earth (E), comprising a tubular drilling robot (1 ) according to one of claims 1 to 29, and a remote control station (14), the remote control station (14) being arranged on the Earth’s surface and connected to the tubular drilling robot (1 ) via cabling (141 ) providing electrical power and optionally control signals to the tubular drilling robot (1 ).31 . A method for drilling a drill bore (200) into the Earth (E), comprising the steps of: providing (S1 ) a tubular drilling robot (1 ) according to any one of the claims 1 to 29; and drilling (S2), using the tubular drilling robot (1 ), the drill bore (200) into the Earth (E).

32. The method according to claim 31 , wherein the step of drilling (S2) includes: producing a hollow cylindrical drill bore (200) that surrounds a solid-material fully cylindrical drill core (201 ).

33. The method according to any one of the claims 31 to 32, further comprising drilling, using the tubular drilling robot (1 ) according to any one of the claims 1 to 29, a further drill bore, in particular an ascending bore, such that the further drill bore is fluidically connected to the drill bore (200), thereby providing a closed-loop flow path designed for circulating a working fluid.

34. The method according to any one of the claims 31 to 33, further comprising the step of displacing drilling fluid by pumping, using an airstream transport system (15), compressed air into the drill bore (200), thereby lifting the drilling fluid out of the drill bore (200).

35. The method according to any one of the claims 31 to 34, further comprising the step of displacing drilling fluid by pumping, using a cascade of sump pumps, thereby lifting the drilling fluid out of the drill bore (200).

36. The method according to any one of the claims 31 to 35, further comprising the step of removing (S3), from the drill bore (200), at least segments of the drill core (201).

37. The method according to any one of the claims 31 to 36, wherein the step of re- moving (S3) comprises breaking-off segments of the drill core (201); and / or the step of removing (S3) comprises a step of transporting the removed, in particular broken-off, segments of the drill core (201) at least partially out of the drill bore (200).

38. The method according to any one of the claims 31 to 37, further comprising the step of: sealing (S4), at least partially, the surface (202) of the resulting drill bore(200).

39. The method according to claim 38, wherein the step of sealing (S4) comprises continuously sealing (S4) the surface (202) by providing on the surface (202) of the resulting drill bore (200) fine-ground debris.

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