Patent Publication Number: US-2016230500-A1

Title: Method and device for the formation of borehole casing by application of material layers by means of kinetic sputtering

Description:
TECHNICAL FIELD 
     The invention concerns formation of a borehole casing by application of material layers by means of kinetic sputtering and a device for its performing, in particular for drilling in geological formations. 
     BACKGROUND ART 
     Stabilization of borehole wall was and still remains an actual problem. In particular how to maximally shorten the exposed section between the drilling location and the most recent casing. One whole category of efforts to temporary or permanently stabilize the borehole is melt-through the borehole wall up to a certain thickness and the formation of a glass or ceramic layer on the surface of the wall. 
     In the sixties and later research work was carried out in this respect in the United States and the Soviet Union. One direction was melt-through the borehole walls (associated with drilling) with a heated body (the penetrator), which pressed the melt into the porous wall and floated the partially fragmented melt to the surface. 
     The second research direction was melting the walls by a plasma jet and its vitrification into glassy or ceramic phase. 
     The third direction was melting the walls of the open borehole from top to bottom using a heated body, which required the borehole to be disconnected from the drilling apparatus. 
     All these performed researches have not led to usable results and were gradually abandoned, mainly for the following reasons:
         even with optimum heating not all rocks exhibit melting at low temperatures and at acceptable energy levels,   disrupted and unconsolidated rock exhibits non-homogeneous melt,   even under optimal course of melting (vitrification), the strength of melt is only at the level of enamel and cannot be influenced by composition nor structure,   cavities or caverns in the wall are not sealable by heating process.       

     For these reasons an alternative to vitrification and reinforcement of the walls of the borehole which would eliminate the abovementioned shortcomings was sought. 
     Such an alternative is the solution of additive coating, which allows the material deposition of the desired composition and the creation of composite structures in the macro as well as micro area during the casing formation. 
     1. The original works on kinetic (cold) sputtering by Alchimov, A. P. et al. in patent RU2010619 “Device for applying coatings”, RF 16187778 from 1991, and in U.S. Pat. No. 5,302,414 “Gas dynamic spraying method for applying a coating” describe the basic principle of kinetic (cold) sputtering and form the basis of all other works. In the next 20-year period this original patent by Novosibirsk team was further developed. It describes all the essential functions and structures, i.e. achieving the necessary application speed of the particles and their temperature below the melting point. 
     An important result in the development of kinetic sputtering was patent RU2063303 by Nesterovi{hacek over (c)}, N. I. et al. “Process of powder compaction”, which describes the solutions where the water steam is used as a carrier gas. The disadvantage of this solution is the high energy consumption to change the phase of the water and its further heating. 
     Another improvement in powder coating is patent U.S. Pat. No. 6,402,050 by Ka{hacek over (s)}irin, A. I. et al. “Apparatus for gas-dynamic coating”, which describes the use of a low pressure and the entry of powder after the narrowest cross-section of the nozzle. The disadvantage of this solution is that powders of heavier metals, for example steel, cannot be applied. The solution to the problem of jet erosion by using a low-pressure system and allowing particles enter the system only after the narrowing of the de Laval nozzle have been needed to improve the equipment energy consumption, costs and life. 
     2. Sputtering onto the inner surfaces of the pipes was a natural step towards formation of layers by surface coating, for example resistant to corrosion, reducing melting and the like. Almost every concurrent apparatus for kinetic sputtering has in its equipment a rectangular nozzle which allows to apply layers on the inner surface of the tubular object. Systems prolonging the life of such nozzles and also substantially increasing the productivity were created. 
     The current situation and state of the art is that the application of layer is only surface treatment with relatively thin coating thicknesses, but the fundamental carrier material (pipe) is still produced in the traditional way. 
     Patent U.S. Pat. No. 7,959,093 by Payne, D. A. “Apparatus for applying cold spray to small diameter pores” where at the bend of a rectangular nozzle auxiliary gas streams without particles are inputted, so as not to permit the stream containing particles to come into contact with the wall of the nozzle, which is thus not exposed to the abrasive action. 
     Patents RU2087207 and RU2089665 by Dukin, J. V. et al “Apparatus for applying powder coats” describes the auxiliary stream in a coaxial nozzle system for 360° powder coating of the inner wall of the pipe at place where the direction changes from axial to radial, wherein the auxiliary protection stream prevents the outer perimeter of the flowing stream containing particles from direct abrasive contact with the wall. 
     Patent RU2075535 by Alchimov, A. P. et al. “Plant for application of coating to internal surface of pipe” describes a device for coating application with a movable nozzle and sucking away powder unattached to the inner surface of the pipe. 
     Patent RU2089665 by Nikitin, P. V. et al. “Device for application of coatings” describes an apparatus for applying powder to the outer surface of the products during the technological process of manufacturing rolled, drawn profiles, which may be of any shape. Similarly, RU2222639 patent (WO 00/56951) by Nikitin, P. V. et al. “The device for deposition of coatings on the internal surfaces of items” describes an apparatus for applying powder to the interior surface of the tubular structures by changing the direction of the supersonic nozzle by 90°, that is into a direction perpendicular to the inner surface. 
     Patent RU2222640 (WO 00/43570) by Nikitin, P. V. et al. “The device for deposition of coatings on the external surfaces of items” describes a device for applying powder to the outer surface of the tubular structures by moving the place of application and also changing the direction of supersonic nozzle into direction perpendicular to the inner surface. 
     A particular problem is the durability of nozzles working with gas streams containing particles. One solution is the principle of nozzles based on hydrodynamic principle with no direct contact of the abrasive particles with the surface of the nozzle material, as described in U.S. Pat. No. 6,348,687 by Brockmann, J. E. “Aerodynamic beam generator for large particles” and in U.S. Pat. No. 8,119,977 Dong-Guen Lee “Aerodynamic lens capable of focusing nanoparticles in a wide range.” These solutions are multistage and thus not effective enough for high pressure and high volume systems. 
     Another very significant issue is the operation of kinetic sputtering system in conditions of liquid medium with different viscosity and at different pressures. 
     The closest analogy are plasma coating, welding, cutting and similar technologies under water. This area is known for a series of solutions that are proven especially for welding and cutting in relatively small depths (up to 100 m). These solutions are indeed a possible conceptual starting point, but because of the necessity of high supersonic speeds of the particle containing working gas and requiring the substrate being without presence of residual water innovative changes are needed. 
     As an example we refer to the U.S. Pat. No. 6,498,316 by Aher B. et al. “Plasma torch and method for underwater cutting” which describes a multiple protective system of gas streams preventing contact of water and plasma stream. It is based on a series of previous patents that share a common effect, aim, but are only variants regarding the geometry and the number of protective streams (U.S. Pat. No. 4,029,930, U.S. Pat. No. 4,291,217, U.S. Pat. No. 4,964,568, U.S. Pat. No. 4,816,637, U.S. Pat. No. 154354, U.S. Pat. No. 486383, U.S. Pat. No. 6,265,689). 
     All these solutions use cold protective streams. An innovation in geometry as well as in stream temperature as described in the present patent is therefore needed. 
     In the area of specialized layers an important role as the deformation zone is played by foamed layers in metallic, ceramic, or in polymeric base. Patent U.S. Pat. No. 7,402,277 by Reghavan et al. “Method of forming metal foams by cold spray technique” describes one possible technique for kinetic sputtering of metal foam. 
     DISCLOSURE OF INVENTION 
     The process of formation of casing in an additive manner by kinetic application of powder material onto the borehole walls allows for continuous forming of casing simultaneously with the process of drilling in geological formations. 
     The nature of the invention lies in that the casing is formed by multiple superposing of deposited layers made of powder material and the material partially obtained from drilled and disintegrated material from the borehole. The particles of the powder material drifting in the carrier gas are, after the impact onto the surface of the borehole walls or onto the mould or the previous layer, formed and shaped, i.e. deposited onto the surface, in such manner as to form the individual layers of the casing on the inner walls of the borehole or on the shaping mould. In order for particles to be deposited on the deposited surface, that is for their shaping, flowing and fusing together into a continuous layer, they must be accelerated and overheated to such a level that upon the impact onto the surface of the borehole walls they are plastically deformed and form a compact layer of casing directly on the borehole wall. Necessary level of acceleration and overheating is different for different materials. The applied material is laid in several layers, forming the carrier layer for the borehole casing. Additional layers are then deposited onto the carrier layer, taking into account functional needs and requirements of the final casing regarding the composition and functions of formed material layers. Requirements for individual layers and their functions define the parameter settings for the input disintegrated material used for each deposited layer. 
     Application of material layers by means of additive kinetic sputtering of metallic, non-metallic and composite materials, utilizes acceleration and heating of powder particles of the material and its subsequent plastic deformation of deformable powder fraction upon the impact onto the surface being deposited. The accelerated and heated powder particles upon the impact onto the surface of the borehole walls and/or onto the surface of the mould, or onto the surface of previous layer of the casing, form a layered composite casing on the inside wall of the borehole or on the mould and that particularly advantageously in a liquid medium. 
     For casing formation such disintegrated rock material is used from which fractions appropriate for the process of kinetic application of powder to casing layer, to place of casing formation on the borehole wall or onto the previous layers of the casing being formed are removed. By controlled thermal treatment of applied layers, material powders and rocks by their overheating and cooling, the stabilized casing is formed. Stabilization and adjustment of casing layers is done continuously by multiple stages concurrently in a series. 
     As for cold kinetic sputtering, a major advantage over conventional drilling technologies is a possibility to form the casing directly from the disintegrated material where geological composition allows it. Compared to melting and high temperature methods of material application onto the walls and the casing formation on the borehole walls, the final product of this technological process does not manifest disadvantageous strength properties of vitrified casing. The subject of present invention is the casing formation by an additive process of powder material accelerated in a carrier gas from powder material deposited in layers onto the borehole walls forming a casing of preferred functional properties, such as tensile strength and compressive strength, pliability, permeability, porosity, thermal insulation, and more. 
     If the geological formation has faults and the borehole wall has for example a “hole” in it, it is necessary to place a mould there to replace the borehole wall at this location, and then the carrier casing layer is formed in such a location right on the sliding mould. 
     At first, the carrier layer of the casing is formed on the borehole wall and/or on the mould in such manner that the material of the carrier layer is applied onto the borehole walls and/or onto the mould in layers, wherein individual layers of the carrier layer have the same or different material composition and the carrier layer preferably forms the composite at the level of microstructure and/or macrostructure, and additional layers of casing can be applied onto the carrier layer. 
     Preferably the casing layers are applied simultaneously around the whole borehole circle perimeter, wherein the deposited surface may vary from roundness and have surface irregularities. Application along the whole circumference is achieved by using a suitable slot in the casing forming device. 
     The acceleration and heating of the particles to be deposited to the borehole walls or to the previous layer of casing is achieved by mixing them with a carrier gas with the appropriate thermal and kinetic energy. The accelerated and heated mixture of particles and the carrier gas exits the nozzle perpendicularly to the borehole wall being deposited or to the previous casing layer from a position close to the borehole wall. The size of the thermal and kinetic energy depends on what material is used to form the casing. Different materials require different levels of energies. 
     Layers of casing are deposited simultaneously in several stages onto the previous casing layer, or onto the borehole wall. 
     Individual layers are simultaneously applied along the circumference of the borehole walls in multiple depositing steps sequentially onto each other. Together they form a carrier layer of casing, which forms coaxial structures with identical or different characteristics, whereby a sandwich and composite structure is formed in casing. The advantage of forming the casing in several layers is that it provides the option to choose the coating geometry around the entire borehole circumference, but also allows to restrict coating just to a sector, for functional or strength reasons. 
     The degree and level of performance of a single layer of coating is in the range of 8-18 g/s, preferably 12-18 g/s. 
     For casing formation, it is preferable that the more layers are deposited in such mariner that the following layers are layered onto one another with a shift, which at the concurrent operation of layer application in multiple stages of apparatus allows for depositing and superposing the layers onto each another. 
     In order to improve the casing properties it is advantageous:
         a) To add to the coating powder specialized additives, reinforcing members in order to improve the mechanical properties of the casing and/or the foaming additive in order to adjust the thermal-insulation and mechanical properties of the casing walls/agents initiating the formation of the porous structures of the casing walls (for example, titanium hydride).   b) To set and regulate the speed of particles and their temperature so that they have an abrasive effect on the applied surface. This also improves the properties of casing.   c) For the coating layer to consist of powder particles which, when applied, form a layer with substantial sliding properties.       

     The resulting casing consists of several layers, some of which may include additives and on the basis of the added additive the properties of the deposited material are regulated not only mutually between individual casing layers, but also along the axis of the formed casing, forming sandwich and composite clusters, thereby adjusting the final properties of the whole casing. It is preferred that the surface of the borehole walls or previous casing layer is treated prior to the application of the layers in such manner that the mixture of carrier gas mixed with particles is not capable of applying (deposition), that is the particles do not contain a binder or the kinetic energy of the carrier gas is out of the range of critical speed for application of rock and mineral particles. In this way the treated surface is mechanically cleaned, roughened, or otherwise treated, which results in a proper surface treatment preparing for application of deposited layers. 
     Deposited casing layers or the borehole wall can be preheated in order to increase the adhesion of subsequent layers, and the efficiency of coating process on the surface of the wall or previous layer before following application. 
     The deposited layers are heated—heat treated to improve the mechanical properties, or to activate foaming additives. 
     Besides deposited layers forming the casing having a carrier function, it is possible to apply a layer with a sliding function. Such a layer may, if appropriate, separate the carrier layers from each other. It is also preferred that such a layer is applied to a mould in such manner that the mould can move alongside the wall of the borehole. 
     The sliding layer will also be used for forming the piping channels in the borehole casing. Sliding one or more moulding tools in such a sliding interlayer creates a hole, which then forms a piping channel in a layered casing along the axis of the borehole. The inlets for media are connected to such formed piping channels, such media are for example powder materials, carrier gas medium, additives, electricity conductors, signal wires, inlets for other materials and others. Sliding the mould tool also moves the connected media that are conducted through the piping hole from the surface of borehole to the drilling and casing device. On the sliding layer, which is formed from materials containing additives to reduce the shear stresses in the layer being applied, one or more layers with the carrier function is subsequently deposited after the formation by the forming tool , to achieve the desired strength of the whole structure. A layer having sliding properties could be for example graphite applied onto the surface with the matrix of lead or tin. 
     It is preferable that at least one layer of the casing is formed from metallic matrix, filling the material obtained by the separation of material disintegrated in the drilling process. Combining application of various materials and metallic materials forming a metal matrix under conditions not much exceeding critical speed of material, and thus exceeding the flow limit for the kinetic application, it is possible to use this method to deposit substantially non-homogeneous materials, as well as to deposit material onto the borehole wall even when the surface of the borehole walls is different from the material surface known to be applicable to. 
     Thus formed layers can be heat-treated by thermal heat flow in various heat treatment modes in order to achieve advantageous metallurgical changes depending on the type of material. Since the individually deposited casing layers during shaping and forming are heat-stressed and upon the impact onto the surface have various properties, these layers are preferably stabilized and their properties are improved through the heat treatment by heat flow in different heat treatment modes in order to achieve the preferred metallurgical changes according to the type of material. Preferably they are annealed and stabilized by the heat flow. 
     In order to increase the efficiency of the process, the fluid of the working environment at the site of application is locally displaced by the stream of carrier gas with particles, or possibly by the stream of protective medium/gas. 
     For effective use and application of the deposited material in the liquid medium, the stream of carrier gas with particles is surrounded by a protective stream, which forms a protective shell between the working environment liquid and the carrier gas with particles and maintains the integrity of the stream of carrier gas with particles, and separates it from the liquid medium, thus reducing energy and material demands of application of layers. 
     The protective stream removes liquid from coated surface and coated surface is prior to the deposition/application dehumidified and preheated. 
     The stream of carrier gas is compressed by the protective stream, which separates the stream of carrier gas with particles from the walls of the nozzle and protects the outlet from direct contact with the material in the outlet, i.e. against the damage and forms a hydrodynamic nozzle. 
     The gases are accelerated and expand preferably using electric arc thermal plasma, causing an increase in pressure by heating and expansion at the contact of carrier gases with the electric arc. Compared to cold kinetic sputtering of metals onto the surface of the materials, which enhances functional properties of the coated surface only, the present method of intensive material application using multi-layering to form a casing carrier layer with the required thicknesses of the carrier casing directly onto the walls of the borehole or the auxiliary mould/template. Mechanical, but particularly thermal drilling disintegrates rocks into small particles which are then correctly separated and those suitable and usable for kinetic coating process are selected, wherein these powder particles are sufficiently accelerated in the carrier gas and then impacted and applied onto the borehole wall or the previous casing layer, thereby forming a casing on the wall of the borehole in a multiple additive manner. 
     It is preferred for the mix of the carrier gases with powder particles in the liquid medium to minimize the stream&#39;s kinetic energy losses at the gas and liquid medium interface by minimizing the distance of the device from the deposited surface and particularly minimizing the loss of an accelerated stream&#39;s kinetic energy using protective flows. The stream of carrier gas with particles is surrounded by one or more protective streams that form a protective sheet between the liquid working environment and accelerated carrier gas mixed with powder particles. This configuration of layered flow streams maintains the integrity of the carrier gas with particles stream, and thereby separates it from the liquid medium and minimizes the losses of kinetic energy of the particles at the expense of shaping the deposited particles onto the deposited surface, by which the protective streams increase the efficiency of surface coating by particles. 
     Exceeding the critical speed of application of powder material onto the surface of the walls, the surface of the walls is abrasively worked and heat-treated into the desired shape or form with the applied material not being deposited but acting as a machining material. This mechanism of disintegration and surface finishing allows to modify the borehole walls to desired roughness and stability for the actual application of layers of casing. 
     The present invention further provides a device for forming the casing layers by material for the borehole walls by an additive powder coating according to the present invention, the nature of which lies in containing at least one stage with an acceleration chamber and a chamber for mixing particles with carrier gas designed for coating and both being connected to the media inlet, to the dosage of coating powder into carrier gas and containing an outlet nozzle, protective nozzles, separating, control and regulatory mechanisms/valves, etc. 
     The outflow nozzle for discharge mixture of carrier gas and particles from the acceleration and the mixing chamber can be placed in a close proximity of the borehole wall to shape the layers of material into a casing. 
     The device can contain multiple in parallel working stages. 
     The carrier gas acceleration chamber contains a pressure increasing module working on the principle of heating and thermal expansion of the gas using electric arc thermal plasma. 
     To ensure the coating of the material all over the borehole circumference it is preferred that the particle carrier gas mixing and acceleration chamber contains the nozzle of an annular shape, in such manner that the nozzle is positioned alongside the circumference of a circle. 
     When appropriate, the outlet of the nozzle embodiment can be made in the form of a slot. 
     The nozzle in the form of a slot is in its circumferential portions surrounded by a hydrodynamic jet, which performs a nozzle protective function. 
     The acceleration and particle mixing chamber can be divided into two parts, namely the acceleration chamber and the particle mixing chamber, wherein the mixing chamber is preferably positioned behind the gas acceleration chamber. 
     Regulatory mechanisms include, in particular, the temperature control and regulation, the control and regulation of carrier gas acceleration and the control and regulation for powder dosage being added into the carrier gas. 
     The main advantages of the solution are following:
         It allows the application of material with desired composition of not only rocks, but also metals, minerals and other morphological structures;   Creating composite structures with desired properties and preferably adjusted strength, rigidity and flexibility;   Consistent use of hydrodynamic (aerodynamic) principles for the protection of device walls and components;   Applying layers of material in flooded environment;   Injecting powders with gas into a shaped stream, protected from outside;   Accelerating, focussing carrier gas and its compression inside with increasing the density and not outside where the gas expands and is a carrier medium for particle acceleration;   Focussing efficiency increases with the pressure of denser environment;   System without physical nozzle, aerodynamic focusing.       

    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a sectional view of a device unit, symmetrical along the borehole axis, for application of particles by kinetic application onto the borehole wall. 
         FIG. 2  shows a sectional view of several stages of rotationally symmetrical slots of an underwater device for application of powders by method of kinetic application method of—kinetic sputtering. 
         FIG. 3  shows a schematic cross-section through the formed casing with a piping distribution system for media supply to the devices. 
         FIG. 4  shows a process sequence in a single stage of kinetic application of casing layer. 
     
    
    
     EXAMPLES OF EMBODIMENTS 
     Example 1 
     Formation of casing using material from disintegrated rock  16  according to the present invention is given by the sequence of processes of treatment and application of powder materials in layers forming a composite casing on the inside wall of the borehole, wherein one preferable embodiment is described by the following steps. 
     The entrance section of the device, i.e. its gas acceleration chamber  3  and mixing chamber  4  for mixing material particles with carrier gas, components of additive application system, being the powder material  8 , additional additives are supplied from an inlet  1  for a coating powder material dosing into the carrier gas, and the carrier and protective gas, preferably in liquid or gaseous form, is supplied through a media inlet  2 . 
     The carrier gas is, in the gas acceleration chamber  3  and the mixing chamber  4  for the material particle mixing using plasma electric arc, accelerated to such speed that accelerates the powder particles to such level that they are upon the impact onto the surface of borehole walls  9  plastically deformed and form a compact layer. This mechanism gives powder particles the kinetic energy required for their layered deposition onto the deposited surface. Thermal effect of the gas expansion is used to accelerate and heat the powder material particles to the temperatures below melting point, while the intensity of the thermal effect is reduced by the phase transition or by heating the carrier medium stream which feeds powder into the gas acceleration chamber  3  and the material particle mixing chamber  4 . In area the gas acceleration chamber  3  and the gas and material particle mixing chamber  4  the particles of the material in the form of a powder are admixed into the carrier gas, wherein the kinetic and thermal energy is transferred to the powder particles of material. Correct level of speed and temperature levels of the resulting mixture of carrier gas and powder particles  8  is regulated by a temperature control and regulation mechanism, and a carrier gas acceleration control and regulation, by setting the desired critical speed and temperature according to the type of material. 
     The prepared mixture of material  8  for application in a carrier gas stream is rendered, through the outlet nozzle  5  in the shape of a slot located on the cylindrical circumference of the device, out from the gas acceleration chamber  3  and the material particle mixing chamber  4  towards the deposited surface or the borehole wall  9  in its vicinity. Such shape of the nozzle allows for the application of powder material alongside the circumference of borehole walls  9 , wherein the application eliminates deviations from roundness and tolerates surface irregularities. Close to the outlet nozzle  5  are the hydrodynamic nozzles  11 , which feed in the protective stream  7  for application and deposition. This protective stream  7  displaces the fluid  15  of surrounding environment, thus creating a working environment for application of powder particles of material contained in the carrier stream. 
     The device for casing application is placed in an annular area between the borehole wall and the drill body  14  of the drilling equipment that at the axis of the borehole comes to drilling apparatus face  13 . 
     In order to intensify the amount of deposited powder material, the applying device consists of several stages. Each stage contains gas acceleration chamber  3  and the material particle mixing chamber  4 . The individual stages deposit layers of casing  12  continuously concurrently in a series, see  FIG. 2 . Not each stage of the device is intended for material coating. According to needs and structure of the deposited casing layers  10 , the various stages of the device apply the layers  10  either homogenously, that is they are the same, or non-homogenously, with different compositions of coating powders. Some stages of the device are designed for heat and/or abrasive treatment of already deposited layers  10  of the casing  12  or of the borehole wall. In such case the stage of the device operates without coating powder. Input of the material into different device stages is controlled by the control and regulation mechanisms for powder dosage into a carrier gas which ensure the delivery of powder materials according to the needs of the desired material composition. In the case of delivery of the same material into several stages in succession, several deposited layers  10  of the casing are the same and form a homogeneous layer  10  of the casing of greater thickness or if different materials are used or additives are added, they form composite layers  10  which strengthens and reinforces the casing  12 . Dosing the foaming additives (for example titanium hydride) and/or initiating agents with the admixed powder and subsequent exposing of the deposited layer  10  to heat only, by the next stage, activates the agents and thereby a porous structure is formed. 
     Method of depositing layers  10  of casing  12  is adapted to functional requirements and needs of the final casing  12  with respect to the composition and functions of material layers forming it. Requirements resulting from the required properties of casing  12  define the characteristics and parameters of inputted disintegrated material: quantity, concentration, gravimetric composition, which is provided by module for control and regulation. 
     The acceleration and mixing chamber  3 ,  4  is supplied with the powder material, which is formed also by the part of material from the drilled and disintegrated rock, from which the fractions appropriate for process of kinetic application of powder layers with required strength and elastomeric properties were separated. 
     By superposing individual layers  10  of the casing  12  onto the borehole walls, a coaxial sandwich structure is formed, composed of layers with different volumes of particles coming from the drilled (disintegrated) rock or minerals. The resulting sandwich structure contains layers with high and layers with low content of these hard particles, thereby forming a composite material of the solid, resistant layer. Thickness of each casing layer, and thus mechanical properties of the casing provided by the composite sandwich structure, can be controlled by adjusting the volume of powder in the carrier gas. The mineral particles are being mixed, mainly with metal particles, which form a metal matrix that bonds the applied mixture of powder material. 
     Example 2 
     A similar device embodiment, which includes most of the features and functional capabilities mentioned in Example 1, but with further functionalities added to the device for additive application of casing: 
     In the chamber  3 ,  4  for gas acceleration and material particles mixing by means of mechanical and thermal expansion of compressed gas the carrier gas supplied from the borehole surface to the entry of the chamber  3 ,  4  for gas acceleration and material particles mixing, supplied through inlet  2 , achieves by its expansion speed that accelerates the powder particles to such levels that the particles upon the impact to the surface of the borehole walls  9  are plastically deformed and form a compact layer  10 . 
     In some stages of the material application onto the borehole wall  9  the layer  10  of material is deposited, which allows to apply the layer or part of the layer, which preferably separates adjacent deposited layers  10  and  12  of the casing and allows to separate also the mould, onto which the layers of the deposited material are deposited. This layer of material has lower shear stresses, which creates friction interface  17  between the layer of the deposited casing and a moulding tool  18 , which forms through its movement with the device in the borehole a piping distribution system  19  in the casing on the borehole wall. 
     The casing is formed in a similar manner by applying layers onto the auxiliary mould of the casing at locations where the device is not close to the borehole wall because of a cavity or cavern. 
     Device components:
           1 . Coating powders and additives inlet     2 . Media inlet for forming carrier and protective gas     3 . Carrier medium acceleration chamber     4 . Carrier gas and particle mixing chamber     5 . Outflow nozzle     6 . Carrier and protective gases exhaust area expelling the surrounding environment     7 . Protective stream from outlet nozzles     8 . Material in the carrier gas stream being deposited     9 . Borehole walls     10 . Deposited casing layers     11 . Hydrodynamic nozzles protecting the stream of carrier gas and particle mixture     12 . Borehole casing     13 . Drilling apparatus face     14 . Drill body—of mechanical or plasma drilling     15 . Surrounding liquid medium     16 . Drilled rock     17 . Sliding layer—interface     18 . Moulding tool for forming piping system     19 . Piping distribution system