EP2920401B1

EP2920401B1 - Process of formation of casing by additive manner in boreholes and device for its performing

Info

Publication number: EP2920401B1
Application number: EP13812204.9A
Authority: EP
Inventors: Ivan Kocis; Tomás KRISTOFIC; Jaroslav LONGAUER
Original assignee: GA Drilling AS
Current assignee: GA Drilling AS
Priority date: 2012-10-24
Filing date: 2013-10-22
Publication date: 2018-09-26
Anticipated expiration: 2033-10-22
Also published as: US20150233206A1; SK500482012A3; WO2014065764A2; WO2014065764A3; EP2920401A2

Description

Technical field

The invention relates to a process of formation of a casing by additive manner, especially in contactless thermal drilling of boreholes in geological formations and a system for its performing.

Background Art

For strength and resistance of borehole walls, the high-quality casing is essential condition for technological use of the borehole during its excavation as well as its durability.
The issue of parallel formation of the casing and drilling process has proceeded through several stages of development. Experiments have been made to solve the issue of narrowing the borehole profile as well as the casing (tapering) by solutions such as expansion of the embedded casing profiles and also by methods of passive insertion of casing during the drilling. Among the first conceptions of casing drilling was the patent US 3661218 . The patent protects a method of casing drilling, but maintains the deficiencies of the rotating drill string of conventional mechanical drilling columns, namely decrescent cross-section. Solutions which can be considered useful and were designed and put into practical use are the principles of drilling with the casing. Analysis of this technology is described in detail in R. Tessari Atall: "Drilling with casing promises major benefits" in Oil & GasJournalVol 97, No. 20 1999 and the article of authors Okeke et al. "Current Trends and Future Development in Casing Drilling". In patent literature the casing drilling, as an example among others, is the object of a patent of company Tesco US6705413 . The company Halliburton has a patent for drilling with a casing for directional drilling in the patent US6877570 . Both mentioned patents have the main common deficiency that the rotating casing may be threatened by collapse of unstable rock from outside and thus by the complete discontinuation of the drilling process. The second common deficiency is that the rotating casing is uncementable during the whole drilling process or it is cementable in parts and the narrowing casing must also be used for the next section.
Utilization of thermal, especially plasma, technologies in formation of a casing is the closest issue to the present invention. These solutions can be divided into two categories. The first includes solutions based on the so-called penetrators i.e. devices, a tip of which heated to the temperature above the melting point of the rock is depressed into the rock, in which it forms a melting vitrified layer and removes the excess material. The second category includes solutions based on plasma thermal flux /torch/, which melts the rock at the bottom and on the walls of the borehole at its exit from the bottom of the borehole.
The example of the first group of solutions is the patent US3693731 "Method and apparatus for tunnelling by melting" by D. Armstrong E. et al., which describes a conical penetrator, which depresses the melt into the pores of the surrounding rock and thus it forms a partially vitrified casing. A large amount of energy is required to achieve acceptable efficiency of the process and speed of penetration.
The line of direct action of heat flux of plasma flow to rock completes the solution of the patent US 8235140 by Wideman T.W. et al. using the mode of so-called spallation, which is energetically preferable. It forms a disturbed layer which may be impregnated and thus it can form a temporary casing. However, the casing formed in this way shows insufficient strength. The patent US 6591920 by Foppe W. uses a molten metal supplied from the surface and heated to a temperature high above the melting point as drilling thermal medium. It depresses the melt into cracks in the rock and thereby forms a casing. But the whole process is considerably technologically difficult. The patent US6851488 by Samith Batarseh describes the formation of a casing by heat radiation flux of laser radiation, which forms a rock melt. It uses compressed air to hold the melt on the wall, and the entire borehole is filled with air as well.
The present invention eliminates the deficiencies of the above mentioned patents in forming of a casing and in the field of efficiency, material and temporal parameters and in particular functionality of casing being formed such as forming of pipe in the casing, sandwich and composite structure of the casing and thereby it surpasses them.
The above-mentioned US patent 6,851,488 of Samith Batarseh : "Laser liner creation apparatus and method", discloses the process (method) and apparatus of creation of the borehole liner by melting the surrounding rock and the cooling and perforating the rock by fluid flow through nozzles. This is the basic difference to the present invention which is based on additive layering of the processed material of the rock and additives to create homogenous layer with the composite composition, and with controllable properties and high strength given by additives.
The patent 6,851,488 belongs to the "penetrator" category which has substantial drawbacks:

a) the resulting structure is influenced by non-homogenous rock, by existing fracks etc., gives no guarantee of quality of the created liner with low strength parameters,
b) the melted rock under the gravitation influence is flowing down and deformed until the cooling fluid flow is applied,
c) it does not solve the vital problem of the transporting simultaneously with the liner creation, and
d) the penetrator concept is generally failed on wrong assumption that the excessive melted rock is pushed into the surrounding rocks fracks. This is the lethal drawback in the referenced patent US 6,851,488 .

The present invention solves these problems in principal way and has the liner composition under full control by additive process as it is solving the transport of melted/evaporated material to the surface.
The patents US 3,907,044 and US 5,735,355 are of penetrator melting category and are not relevant to the additive layering concept of this invention.

Disclosure of Invention

The mentioned deficiencies are to the great extent eliminated by the process of formation of the casing by additive manner especially in thermal drilling of boreholes in geological formations and devices for its performing according to the present invention. The nature of the present invention consists in that the casing is formed by layering material from vaporized rocks by condensation and solidification on borehole walls. In formation of the casing, the material of the vaporized rock and thermal energy inserted into it are used so that by a heat treatment a mixture of vaporized rock vapours passes through phase transformations, namely to a liquid phase and a partially solid phase, and mechanical treatments and transport of the rock material from a source of generation of hot gas mixtures, namely mixtures of vaporized rock vapours and vaporized coolant vapours to an area of formation of the casing by directing and application of the treated rock material in the area of the casing formation to the borehole wall or to the underlying layers of the casing being formed. The layered casing is formed by cooling the rock material, wherein the casing layers formation is continuous.
In thermal drilling, the main advantage over conventional drilling technologies is the possibility to form the casing directly from disintegrated material. The object of the present invention is formation of the casing by additive process from melted and vaporized rock material applied in the layers to the borehole walls, by which the casing of required characteristics such as tensile strength, compressive strength, compliance, permeability, porosity, thermal insulation properties and others.
Rocks material meltdown and vaporization occur especially in thermal drilling of boreholes, where from them and from coolant transported to the place of drilling are generated the hot gas mixtures consisting of vaporized rock vapours and coolant, where cooling gases are formed by its vaporization, wherein by taking over the carrying function, also carrier gases are subsequently used for formation of the casing by additive manner in the process of formation of the casing according to the present invention.
The heat treatment is a cooling, in which the generated hot gas mixtures are cooled by coolant. A phase transition of a rock vapours occurs by their cooling and by condensation liquid particles of rock and by solidification solid particles of rock are formed in the flowing mixture of rock material and cooling gases.
The generated hot gas mixtures of vaporized rock vapours and cooling gases are divided by mechanical treatment into at least two main streams. At least one stream is a stream of cold materials and at least one stream is a stream of hot materials.
Since not the entire material from melted and vaporized rocks is necessary for formation of the casing, it is necessary to separate the excess part of this material together with the cooling gases from the part, which will be used for formation of the casing. Therefore at least from one of these main streams other sidestreams are further continually diverging, by which excess mixtures of rock materials and cooling gases are led away to the waste. The part of the rock material from which the casing will be formed remains in the streams of cold and hot materials.
At least one stream of hot materials and at least one stream of cold materials are formed by heat treatments which is a multistage cooling of rock materials by controlled heat transformation, wherein at least two main streams are cooled to different temperature so that the stream of cold rock materials is cooled to the temperature at which gas rock material is transformed into the solid phase and solidifying rock particles are formed, which solidify before their application as the casing layer, and the stream of hot rock materials is cooled above the temperature of the rock melting, which allows them to be mixed with cold materials and thus to form the continuous casing layer, in which layers during the heat exchange between particles occur temperature decrease of entire layer, phase transformation and thus formation of continuous casing layer. Temperature of particles in the stream of cold materials and in the stream of hot materials is different before application of the casing layer.
Waste gases, which are excess parts of cooling gases, are led away to the waste from main streams of materials by further mechanical treatments, namely by separation, and thus the streams of solidifying rock particles formed by cooling the mixtures of hot rock vapours and cooling gases, which are at the same time the carrier gases, are concentrated.
Discharge of waste cooling gases is necessary also because the coolant is continuously added as cooling and as protective and separating layer between all contact areas of the device and the mixture of hot flowing gases. Since during the process of drilling and also for the process of the casing formation it is constantly necessary to supply coolant, it is also constantly necessary to separate excess parts of cooling gases from main streams of materials and to discharge them into the waste. The concentration of mixtures of main streams, which already contain solidifying parts formed by cooling the hot rock vapours mixtures in the stream of cooling gases, is accomplished by discharge of the excess parts of cooling gases.
Cooling gases are formed by vaporization of supplied coolant and cooling gases also take over the carrying function, since they simultaneously carry rock particles, which solidify in the system, and therefore they are also carrier gases. Removed heat and temperature decrease of the resulting mixture is performed by phase transformation of the coolant, mixing the parts of the mixture and expansion of the mixtures of vaporized rock and cooling gases.
After dividing and separating the mixtures of excess rocks material and cooling gases, the streams of the mixtures of rock material and cooling gases are divided into smaller streams by mechanical treatment, namely by division into n number of channels, for the purpose of their additional treatment.
The step of separation of the excess parts of cooling gases is followed by further mechanical treatment, namely increasing the speed of cold and hot rock particles before mixing them, which is performed to accelerate and direct them.
The coolant also provides thermal protection to the device so, that the coolant is continuously added as a cooling and also protective and separating layer between all contact areas of the device and the mixture of hot flowing gases.
Mixing of cold particles and hot particles occurs by connecting the stream of cold materials with the stream of hot materials, and the mixture of rocks material is formed, which is at first applied to the borehole wall and subsequently additional layers are applied on the underlying layers of the moulded casing.
The formed casing layer solidifies especially during further heat treatment, which is self-cooling, wherein internal heat transfer occurs in the applied layer, namely by heat exchange between applied hot and cold particles of the rock material in the casing layer.
In the area of casing formation, a moulding device is embedded, by sliding of which an aperture is formed in the solidifying casing, which forms pipe channels in the layered casing along the borehole. A medium supply such as a coolant pipeline, an electricity conductor, a signal conductor and others, is conveyed to the slid moulding device.
Mixing of cold and hot rock particles is performed by action of opposing centrifugal forces, which empty into a common area in a channel of formation of casing layers leading into the area of application of casing layers.
Cooling of the formed casing must be controlled, wherein the formed casing layers are tempered and cooled. Hot waste gases, alternatively cooled by addition of cooling gases, are preferably used for controlled cooling of the casing.
Cooling and condensation of discharged waste rock material provide cooling of cooling gases and excess rock material to the temperature in the range of 100-250 °C.
By sliding of one or several moulding devices in the solidifying casing, an aperture is formed, which shapes the pipe channel in the layered casing along the borehole, where a medium supply, in particular a coolant pipeline, an electricity conductor, a signal conductor and others, is conveyed to the slid moulding device. Connected medium supplies, which are led by the formed aperture from the surface of the borehole, are also slid by sliding of the moulding device.
In order to improve the properties of the casing, it is advantageous to add specialized additives to the flowing mixture, which comprise:

a. an increased supply of coolant for control the cooling of the mixture of rock vapours and cooling gases in order to form expansion joints in the casing using controlled cooling of applied material; and/or
b. reinforcement elements in order to improve the mechanical properties of the casing; and/or
c. a foaming additive in order to adjust thermal-insulating and mechanical properties of the walls of the casing.

Addition of particular additives is preferably performed before mechanical treatment of increasing the speed of cold and hot parts, and especially before mixing them in the process of acceleration of particles, namely by addition of additives to various sub-groups of n number of channels and thus materials are formed, which after application form one or more coaxial structures with the same or different characteristics, and thereby a sandwich and composite structure is formed in the casing.
The resulting casing consists of several layers, wherein some of the layers may contain also additives and properties are adjusted not only reciprocally among individual casing layers, but also along the axis of the formed casing, with regard to the added additive, thereby they form sandwich and composite aggregations and thus adjust properties of the entire casing.
A device for performing the process of formation of the casing by additive manner, especially in thermal drilling of the boreholes in geological formations according to present invention comprises the following technological parts:

a hot rock vapours mixture formation block;
mechanical treatments modules;
heat treatments modules;
transport modules;
directing and application modules.

A hot rock vapours mixture formation and cooling gases block is a high-temperature energy flow, which produces the vaporized rock forming hot rock vapours mixed with cooling gases entering into the casing formation.
The mechanical treatments block includes:

a mechanical division and separation block;
a separation and concentration block;
particles division and acceleration blocks;
a system for mixing the particles;
an output streams separator.

The heat treatments block includes:

a cooling system;
a controlled cooling block.

The hot gases mixture cooling system is a group of channels, in which the hot mixture is cooled by the coolant in order to change the phase by cooling. By cooling, both liquid and solid particles of rock are formed in the flowing mixture. The group of channels of the cooling system is also designed for protection of walls of active and exposed parts of the device.
The directing and application block includes a casing layers formation channel. This channel is a mixing slot, where solid and liquid particles of the flowing mixture are applied on the wall by kinetic energy and then they are deposited as the casing layers. After application, the hot particles in the layer are cooled autonomously, without the need for external cooling, with heat interchange between the hot and cold deposited fractions. And the casing layers formation channel is designed for discharge of cooling gases and excess particles of rock into the waste as well.
The mechanical division and separation block consists of a system of branching channels and separators separating volumes of the mixture of rock materials and cooling gases into the other blocks, as necessary.
Additional functions mechanisms may be controlled dispensers for adding the additive and these dispensers may be:

a. a dispenser of coolant for cooling the hot and cold material for separation/disruption of the formed casing by the expansion joint, and/or
b. dispensers of reinforcing concrete elements for improving the mechanical properties, and/or
c. dispensers of foaming additives for improving and treatment of thermal-insulation and mechanical properties of the casing walls.

Device comprises also a system of channels for additives dosage control into sub-groups of n number of channels in particles division and acceleration module, where it generates several treated streams of materials. These streams of materials form coaxial sandwich and composite structures of the casing not only along the layers which are layered in the casing, but also in radial direction relative to the axis of the borehole.
The separation and concentration of the mixtures of rock particles and gases block is a group of separators, by which division, separation and discharge of the cooling gases is performed in the guide channels, where the cooling gases are separated and the mixtures of rock particles and gases are concentrated to the desired concentrations.
The particles acceleration blocks are accelerating centrifugal devices increasing the kinetic energy of particles.
The system for mixing the particles of hot and cold streams from directing and accelerating part is a flow mixer of flowing cold and hot materials into the casing formation channel, wherein the particles are in the step of directing and acceleration directed and applied in the casing layer in the casing formation channel.
Device also preferably comprises a block of sliding forms of pipelines in the casing, which is a system of forming members, which are designed for formation of the pipe channel in the layered part of the casing along the borehole.
The output streams separator is a separator at the outlet of the casing formation channel, which separates excess materials discharged out of the casing formation channel and parts of the hot gases for tempering the casing by controlled cooling.
The controlled casing cooling block is a tempering and cooling system at an interface of the casing and the device.
The device also comprises a waste outlet, by which the collecting and cooling device discharges all excess rocks and cooling gases materials, which are cooled to the temperature below the temperature of the device resistance.
The system for mixing the particles consists of two systems of centrifugal channels, which are orientated against each other, wherein they may together form an obtuse angle, and they lead into the common area in the casing layers formation channel.
The hot mixture formation block may preferably have an annular shape of cross-section similar to the casing being formed; thereby it allows performing standard mechanical drilling or core drilling in the central area of the annular casing formation.
The present invention has the following advantages when compared to the prior art:
The used technology uses the disintegrated rock material itself and the energy inputted in them in eroding to form the casing. Due to the casing formed according to this invention, the borehole is stabilized and protected against invasive action of materials from geological action of surroundings. By formation of the composite and laminated casing, the mechanical properties of the borehole are structurally improved. The casing of the walls is corrosion resistant and from this point of view it has longer lifetime. The logistical procedures of conventional technology are eliminated, thus reducing time demands and financial burdens of the deep boreholes formation.

Description of drawings

Fig. no. 1 shows a technological scheme of casing formation.
Fig. no. 2 shows a scheme of the mechanisms of casing formation by additive method.
Fig. no. 3 shows a cross section of the borehole as the base for forming annular casing and pipes for distribution of media and supply of energy.
Fig. no. 4 shows a flow of cold and hot materials and their mixing in the casing layers formation channel.
Fig. no. 5 shows conical pipe formation.
Fig. no. 6 shows a layered formation of the casing by different functional parts in the radial direction.

Example of the Embodiment

The formation of the casing from the disintegrated rock according to this invention is given by the sequence of treatment processes and coating of the rock vapour materials in the casing layers, by their autonomous cooling, when the casing is formed on the walls of the borehole. This occurs in the for casing formation, which provides the formation of the casing especially in the thermal drilling of the boreholes in geological formations according to the invention, in which one preferred embodiment is described in the following steps.
The hot mixture of the vaporized rocks vapours and vaporized coolants vapours, which in certain phase of the technological process become carrier gases, with the temperature higher than the boiling point of each of the rocks fractions, enters the input part of the device for casing formation by an additive manner, i.e. the hot mixture formation block 1. In the block 2 of the mechanical distribution, this mixture of vaporized rocks vapours and vaporized coolant vapours is divided into two main streams. These two main streams are cooled to different temperatures in the selective and controlled cooling block 3. One stream is cooled so that the main and essential part of the flow is condensed and subsequently solidified particles. This stream, containing 60-90 weight %relative to the weight of the vaporized material flow of the entering mixture of vaporized rock vapours and vaporized coolant vapours, is a stream of cold material. From the stream of cold material, the excess mixtures of vaporized rocks vapours and vaporized coolant vapours are discharged into the waste channel of the waste part of the device 12 in an amount of 50-70 weight % relative to the weight of flow of vaporized material, which does not participate in the formation of the casing 13, prior to its further treatment. In the second flow of the mixture of vaporized rocks vapours and vaporized coolant vapours containing 10-40 weight % relative to the weight of flow of vaporized material of the entering, these mixtures are cooled so that the main and essential part of the flow are gaseous and liquid fractions, thereby the nature of the flow of hot material is given.
All parts of the device, which come into contact with streams of flowing gases and high temperature vapours, are necessarily protected from their thermal effects. Protection is carried out by the surface cooling of functional bodies of the device, namely by continuous addition of the coolant. Except for the mentioned protective function, the coolant also performs a technological function, wherein the controlled cooling of the mixture of gases and vapours is controlled by its amount, namely by blending it in the mixture of gases and vapours; thereby the final mixture reaches the required temperature at which it has the desired functional properties. Heat transfer between coolant being mixed and rock vapours uses the latent heat by phase transition of the coolant and the heat consumed by the expansion of the mixture of the vaporized rock and cooling gases for cooling the final mixture. Addition of the coolant is controlled and realized by the selective and controlled cooling block
By adding further coolant to the mixture of vaporized rocks vapours and vaporized coolant vapours, the total volume of flowing mixtures is increasing and thereby their temperature is decreasing and required fractions for further processing are being formed. The flowing mixture consists of technological fractions, i.e. of the rock material in a gas and/or liquid and/or solid phase, and of refrigerants. Excess cooling gases, which fulfil also the function of the carrier gases, are separated in the separation block 5 and discharged into the waste channel 12. The concentrated stream of gases and solidifying particles of rock continues to the area, where additives of reinforcing elements and/or foaming reagent in the line of cold materials are added or the hot concentrated mixture is cooled in order to form expansion joints by controlled cooling in the lines of cold materials and hot materials. Injection of additives is provided by mechanisms 4 of additional functions.
In both streams, namely in the stream of cold materials and in the stream of hot materials in particles distribution and acceleration block 6 streams of mixtures are divided into three groups of channels, and in the first group are 6 pairs of channels, in the second group are 6 pairs of channels, and in the third group are 12 pairs of channels. These groups of channels are arranged so that they cover the whole surface of the casing width. The pairs of channels refer to two channels directed against each other. One channel is for cold material and the other channel is for hot material. Into the groups of channels, various additives are added, and thereby different mixtures of materials are formed and these flow in the appropriate groups of channels. In the first group, the material is treated so that the additives of reinforcement elements are added. The material modified in this way is further divided into 6 pairs of channels. In the second group, the material is not modified by adding additives. The material modified in this way is further divided into 6 pairs of channels. In the third group, the material is modified so that the foaming additives are added. The material modified in this way is further divided into 12 pairs of channels. Streams of mixtures of vaporized rocks vapours and vaporized coolant vapours are then accelerated to increase their kinetic energy. Increasing the speed of the particles is performed for the purpose of acceleration and direction, especially in the direction of the normal to the layers of the casing by inputting the kinetic energy into the cold particles and hot particles in the accelerating sections before entering the moulding channel 9 of the casing formation. Outlets of the channels of cold materials and hot materials of the streams are situated alternately in the mixing particles system 7, wherein the mixing of hot and cold material occurs by the outflow from each of these channels, wherein solid and liquid fractions are applied perpendicularly to the wall of the casing (Fig. 3). Different properties of materials flowing from different groups of channels allow to apply mixtures with different concentrations of cold particles, hot particles and additives, and thereby the applied layer (Fig. 6) forms the sandwich and composite arrangement with advantageous properties of the casing not only by modification of the properties of the applied layers over time, but also by applying different materials from the groups of channels in the direction of the axis of the applied casing.
Particles flowing against each other are mixed by the effect of the centrifugal forces and applied to the wall or subsequently to the underlying casing layer 13, wherein they solidify by self-cooling during heat transfer in the applied layer between deposited hot, liquid and cold particles of the intermingled streams of cold materials and hot materials in the casing layer 14. Cooling gases and residues of non-applied rock particles are lead away along the casing being formed into the wasted part 12 of the device. The casing is temperated by controlled cooling of the waste mixtures using the hot vapours, which allows inside tensions in the formed casing to relax and to temper the casing by the separated vapours and gases of the discharged and excess material in the separator 10 of output streams, which are not involved in the formation of the casing and is lead away into the waste part of the device.
In the waste part of the device 12, all fractions of residual/surplus material are cooled, wherein they are mixed to the final temperature of the carrier hot and cooling gases and residual rock material, most preferably in the range of 100-250°C, less preferably in the range of 200-450°C.
In the formed peripheral casing layer (Fig. 4), the pipelines are formed by the moulding tool. By sliding the moulding tool in one such a pipeline, the aperture (Fig. 5) is being formed in the solidified casing in the direction of the casing formation, which forms the pipe channel along the borehole. To the body of the shifted moulding tool 16 of the piping formation block 8, the supply 15 of a medium, such as water, conductor of electricity, signal cables and others, is connected.
The sequence of preparation and formation of the casing is shown schematically in the Figure 1.

List of Reference Signs:

1. A hot mixture formation block
2. A mechanical division block
3. A selective and controlled cooling block
4. Additional functions mechanisms
5. A separation block
6. Distribution and acceleration of particles blocks
7. A system for mixing particles
8. A pipeline forming block
9. A casing formation channel
10. An output streams separator
11. A casing controlled cooling block
12. A waste part of a device
13. A layered casing
14. An applied layer of a casing
15. Media supplies
16. A moulding tool
17. A borehole drilled by conventional or other technology
18. A rock

Claims

A process of formation of a casing in boreholes in additive manner, specifically in thermal drilling in geological formations, wherein
- a vaporized rock and thermal energy inserted into the vaporized rock are used so that by a heat treatment a mixture of rock vapours passes through phase transformations, specifically to a liquid phase and a partially solid phase,

- the heat treatment is a cooling in which the generated hot gas mixtures are cooled by coolant, by their cooling a phase transition occurs and by condensation liquid particles of rock are formed and by solidification solid particles of rock are formed in flowing mixture of rock material and cooling gases,

- the generated hot gas mixtures are divided by fluid-mechanical treatment into at least two main streams, at least one stream is a stream of cold materials and at least one stream is a stream of hot materials, and at least from one of these streams other sidestreams are further diverging by which excess mixtures of rock materials and cooling gases are led away to the waste, wherein a part of the rock material from which the casing will be formed remains in the stream of cold and hot materials,

- at least one stream of hot materials and at least one stream of cold materials are formed by heat treatment which is a multistage cooling of rock materials by controlled heat transformation, wherein at least two main streams are cooled to different temperature so that the stream of cold rock materials is cooled to the temperature at which gas rock material is transformed into the solid phase and solidifying rock particles are formed, which solidify before their application as the casing layer, and a stream of hot rock materials is cooled to the temperature which is above the temperature of melting and which allows them to be mixed with cold materials, thereby the formed mixture is cooled to the temperature below the solidification point and thus it forms a firm continuous casing layer,

- transport of the rock material from a source of generation of hot gas mixtures, specifically mixtures of rock vapours and coolantvapours, to an area of formation of the casing by directing and application of the treated rock material to the borehole wall or to the underlying layers of the casing being formed, in the area of the casing formation, and by cooling the rock material, the layered casing (13) is formed, wherein the casing layers formation is continuous,

- by further fluid-mechanical treatment, specifically by mixing of cold rock particles and hot rock particles, a mixture of rock material is formed, which is applied to the borehole wall, wherein it forms the first casing layer, and then it is applied to the underlying layers of the moulded casing and forms additional layers.
The process of formation of the casing according to claim 1 characterized in that, waste gases, which are excess parts of cooling gases, are led away to the waste from main streams of materials by further fluid-mechanical treatment, specifically by separation, and thus the streams of solidifying rock particles formed by cooling the mixtures of hot rock vapours and cooling gases, which are at the same time the carrier gases, are concentrated.
The process of formation of the casing according to any of claims 1 and 2 characterized in that one of the heat treatment methods is a cooling by expansion of mixtures of vaporized rock and cooling gases.
The process of formation of the casing according to any of claims 1 to 3 characterized in that the step of separation of the excess parts of cooling gases is followed by further fluid-mechanical treatment, specifically by increasing of speed of cold and hot rock particles before mixing them, which is performed to accelerate and direct them.
The process of formation of the casing according to any of claims 1 to 4 characterized in that the coolant also provides thermal protection to the device so that the coolant is continuously added as a cooling, protective and separating layer between all contact areas of the device and the mixture of hot flowing gases.
The process of formation of the casing according to any of claims 1 to 5 characterized in that the formed casing layer solidifies during further heat treatment, which is self-cooling, wherein internal heat transfer occurs in the applied layer, specifically by heat exchange between applied hot and cold particles of the rock material in the casing layer.
The process of formation of the casing according to any of claims 1 to 6 characterized in that in the area of casing formation a moulding device (16) is embedded, by sliding of which an aperture is formed in the solidifying casing, the aperture forms pipe channels in the layered casing (13) along the borehole, where a medium supply, such as a coolant pipeline, an electricity conductor, a signal conductor and others, is conveyed to the slid moulding device (16).
The process of formation of the casing according to any of claims 1 to 7 characterized in that mixing of cold and hot rock particles is performed by action of opposing centrifugal streams of mixtures, which empty into a common area in a channel of formation of casing layers leading into the area of application of casing layers.
The process of formation of the casing according to any of claims 1 to 8 characterized in that cooling of the casing is controlled by further heat treatment, in which hot waste gases are used, which are controlled by mixing with the coolant so that they temper and/or cool the formed casing.
The process of formation of the casing according to any of claims 1 to 9 characterized in that cooling and condensation of discharged waste rock material provide cooling of cooling gases and excess rock material to the temperature in the range of 100-250 °C.
The process of formation of the casing according to any of claims 7 to 10 characterized in that by sliding the moulding device, also connected media supplies are slid to the formed apertures, in particular of media such as coolant pipelines, conductors of electricity, signal conductors, and others, which are led by a generated aperture at the surface of the borehole.
The process of formation of the casing according to any of claims 1 to 11 characterized in that specialized additives are added to the flowing mixture of rock material and cooling gases, which comprise:
a. an increased supply of coolant for control the cooling of the mixture of rock vapours and cooling gases in order to form expansion joints in the casing using controlled cooling of applied material; and/or

b. reinforcement elements in order to improve the mechanical properties of the casing; and/or

c. a foaming additive in order to adjust thermal-insulating and mechanical properties of the walls of the casing,
wherein addition of particular additives is performed before fluid-mechanical treatment of increasing the speed of cold and hot parts.
The process of formation of the casing according to any of claims 1 to 12, characterized in that by different treatment of streams by addition of additives into the groups of channels, different materials are formed, which are further divided and after application they form one or more coaxial structures with the same or different characteristics, and thereby a sandwich and composite structure is formed in the casing.
A device for performing the process of formation of the casing by additive manner, specifically in thermal drilling of boreholes in geological formations according to any of claims 1 to 13, the apparatus comprising the following technological parts:
- a hot rock vapours mixture formation module (1),

- fluid-mechanical treatment modules,

- heat treatment modules,

- transport modules,

- directing and application modules;
wherein:
- the hot rock vapours mixture formation module is a hot rock vapours and cooling gases mixture formation module (1), which is a high-temperature energy flow generator, which produces the vaporized rock, forming hot rock vapours mixed with cooling gases entering into the casing formation;

- the fluid-mechanical treatment modules include:
• a fluid-mechanical division and separation block (2) which consists of a system of branching channels and separators separating volumes of the mixture of rock materials and cooling gases, as necessary, into the following blocks;

• a separation and concentration block (5) which is a group of separators, by which division, separation and discharge of the cooling gases is performed in the channels, where the cooling gases are separated and the mixtures of rock particles and gases are concentrated to the desired concentrations,

• particles division and acceleration modules (6) which are accelerating centrifugal devices increasing the kinetic energy of particles,

• a system (7) for mixing the particles which consists of two systems of centrifugal channels, which are orientated against each other and lead into the common area in the casing layers formation channel (9),

• an output streams separator (10) which is a separator at the outlet of the casing formation channel (9), which separates excess materials discharged out of the casing formation channel (9) and parts of the hot gases for tempering the casing by controlled cooling;

- the heat treatment module includes:
• a cooling system (3), which is a group of channels, in which the hot mixture is cooled by the coolant in order to change the phase by cooling, wherein by cooling both liquid and solid particles of rock are formed in the flowing mixture and it is designed also for protection of walls of active and exposed parts of the device,

• a controlled cooling block (11) which is a tempering and cooling system at a interface of the casing and the device;

- the directing and application modules include a casing layers formation channel (9), which is a mixing slot, where solid and liquid particles of the flowing mixture are applied on the wall by kinetic energy and then they are deposited in the casing layers and after application the hot particles in the layer are cooled autonomously, without the need for external cooling, with heat interchange between the hot and cold deposited layers, wherein the casing layers formation channel (9) is also designed for discharge of cooling gases and excess particles of rock into the waste.
The device for performing the process of formation of the casing according to claim 14 characterized in that it further contains additional functions mechanisms (4), by which dispensers for adding the additives are controlled and these dispensers may be at least:
• a dispenser of coolant for cooling the hot and cold material for separation/disruption of the formed casing by the expansion joint and/or

• dispensers of reinforcing elements for improving the mechanical properties and/or

• dispensers of foaming additives for improving and treatment of thermal-insulation and mechanical properties of the casing walls.
The device for performing the process of formation of the casing according to any of claims 14 and 15 characterized in that it further comprises groups of channels for additives dosage control in particles division and acceleration module (6), where it generates differently treated streams of materials, which form coaxial sandwich and composite structures of the casing, not only along the layers which are layered in the casing, but also in radial direction relative to the axis of the borehole.
The device for performing the process of formation of the casing according to any of claims 14 to 16 characterized in that the system (7) for mixing the particles of hot and cold streams from directing and accelerating part is a streams mixer of flowing hot and cold materials into the casing formation channel (9), wherein the particles are in the step of directing and acceleration directed and applied in the casing layer in the casing formation channel (9).
The device for performing the process of formation of the casing according to any of claims 14 to 17 characterized in that it further comprises a block (8) of sliding forms of pipelines in the casing, which is a system of forming members, which are designed for formation of the pipe channel in the layered part of the casing along the borehole.
The device for performing the process of formation of the casing according to any of claims 14 to 18 characterized in that it further comprises a waste outlet (12), by which the collecting and cooling device discharges all excess rocks and cooling gases materials, which are cooled to the temperature below the temperature of the device resistance.
The device for performing the process of formation of the casing according to any of claims 14 to 19 characterized in that the hot mixture formation module (1) has an annular shape of cross-section similar to the casing being formed and thereby it allows to perform standard mechanical drilling or core drilling in the central area of the annular casing formation.
The casing formed by the process of formation of a casing in boreholes in additive manner according to any of claims 1 to 13.
The casing formed by the device for performing the process of formation of the casing according to any of claims 14 to 20.