WO2016036280A1 - Device and method for thermal protection of a submersible electric motor - Google Patents

Abstract

The invention relates to the petroleum extraction industry and can be used for extracting petroleum from deep and ultra-deep wells using electric centrifugal pump assemblies. In order to prevent the current lead of a submersible electric motor from overheating because of a heat flow passing along a power supply cable which extends along a pump housing, and in order to extend the period of operation of an electric centrifugal pump assembly between maintenance sessions, and in order to increase the operational efficiency of an electric centrifugal pump assembly and decrease petroleum extraction losses when extracting same from deep and ultra-deep wells, an electric centrifugal pump assembly for an oil well contains, adjoining one another, an electric centrifugal pump and a submersible electric motor with an electric cable which is adjacent to the pump housing, and contains a means for the thermal protection of a submersible electric motor, said means being in the form of supports which are positioned between the pump housing and the electric cable, said supports being capable of fixing the position of the electric cable relative to the pump housing, with a gap between the pump housing and the electric cable, allowing for well fluid to circulate in the gap between the pump housing and the electric cable, the supports having a small area of contact with the pump housing.

Description

 DEVICE AND METHOD OF HEAT PROTECTION

 SUBMERSIBLE MOTOR

Technical field

The invention relates to the oil industry and can be used for oil production through the installation of electric centrifugal pumps from deep and superdeep wells with a depth of up to 3 thousand meters vertically and high gas content (up to 250 - 500 m ³ / m ³ ).

 State of the art

The installation of an electric centrifugal pump for deep and ultra-deep wells (with a depth of up to 3 thousand meters vertically) and a high gas content in the borehole fluid (up to 250 - 500 m ³ / m ³ ) is located in the production casing of an oil well and consists of interfaced to each other a submersible electric motor, hydraulic protection, with receiving holes, a pump, a tubing string and an electric cable that provides electric current to a submersible electric motor through a current lead (or through a plug - the connection point ayuschego cable to the windings of the motor).

When starting the installation of an electric centrifugal pump in operation, a decrease (drop) in the dynamic level of the fluid in the well first occurs. In this case, liquid enters the pump inlet openings from above. There is no movement of fluid near the submersible motor when the unit is started up. During this period, about 30 minutes, there is a slight increase in the temperature of the submersible motor, but due to contact heat transfer between the casing of the submersible motor and the production casing of the oil well, the temperature of the submersible motor does not increase more than 80 - 100 ° C.

 Next, the productive formation begins to “work”, formation fluid begins to flow to the installation of the 5 electric centrifugal pump, and the temperature of the submersible electric motor drops to 50 - 65 ° С.

 During the operation of the well, the space between the receiving holes of the pump and the dynamic level is gradually replaced by pure oil [1. Gareev A.A. Calculation of the gas separation coefficient at the pump inlet, Yu M. f. Oil industry, 2013. NQ 3, pp. 82 - 85].

 As the dynamic fluid level in the well decreases, the pressure at the pump intake decreases and becomes less than the saturation pressure of the associated gases dissolved in the oil, which, according to the laws of underground hydraulics, leads to the release of associated gas from the oil [2. Mishchenko IT. Downhole production of 15 oil. Because of the "Oil and Gas" Russian State University of Oil and Gas. I.M. Gubkina. 2003. p. 424, 476].

 When associated gas is extracted from oil, carbonated liquid begins to flow into the installation of the electric centrifugal pump, the efficiency of the installation drops and the pump starts to heat up [3. Gareev A.A. About the value of the temperature regime

20 in installations of electric centrifugal pumps. M. Zh. "Equipment and Technologies for the Oilfield Complex", NQ 1. 2009; 4. Gareev A.A. On temperature conditions and the phenomenon of heat stroke in an electric centrifugal pump. “Oil industry”, NQ 3, 201 1, p. 122 - 126; 5. Drozdov A.N. Development, research and industrial use results

25 submersible pumping and ejector systems for oil production. (Dis. Doctor of Engineering Sciences - M, 1998); 6. Drozdov A. N. Influence of free gas on the characteristics of deep pumps. -Oil economy, 2003, N ^Q 1].

 Due to the heating of the pump, there is a constant heating of the layers of oil surrounding the pump, which leads to the constant release of gas bubbles on the surface of the pump c3 (due to the proportional dependence of the saturation pressure on the oil temperature).

Since the associated gas has dozens of times lower thermal conductivity than the well fluid, in a pump surrounded by gas bubbles, which is in a “thermostat”, the amount of heat increases and the pump can be heated to temperatures of 300 ° C or more, as a result of contact heat exchange, the heat flux of the pump housing is transferred to the cable extension (part of the cable line adjacent to the pump housing).

 Excessive overheating of the pump leads to heating of the power cable adjacent to the pump casing 5, then along the cable line to overheating of the current lead and failure of the submersible motor in place of the current lead.

 [7. Gareev A.A. On the temperature regime and the phenomenon of "heat stroke" in an electric centrifugal pump. Oil industry. N ° 3. 2011, p. 122 - 126.].

 Manufacturers of electric centrifugal pump installations do not take into account the spread and penetration of heat flux through the conductors and lead (metal) armor of the supply cable into the submersible electric motor - this process is simply ignored [7. Gareev A.A. On the temperature regime and the phenomenon of "heat stroke" in an electric centrifugal pump. Oil industry. Ns3. 2011, p. 122 - 126.].

 15 To protect against the influence of heat flux from the pump side, the supply electric cable is made of heat-resistant material with an operating temperature of 230 ° C and equipped with lead armor to dissipate heat into the liquid layers surrounding the pump. This does not take into account the process of heat distribution through lead armor and copper conductors to the side

20 of the current input and does not take into account the effect of high temperature on the state of the current input.

 The operating temperature of the submersible motor is 130 ° C.

 The maximum permissible temperature of the submersible motor is determined by the temperature of the solder melting - not more than 180 ° C.

25 When heat flux with a temperature of more than 180 ° C penetrates into the current lead, the soldered ends of the motor windings in the current lead are unsoldered (destroyed), a short circuit occurs and the electric motor of the electric centrifugal pump installation fails.

In this regard, the urgent task of thermal protection of the current input of the submersible electric motor in the installation of an electric centrifugal pump to increase the overhaul period of its operation by protecting the submersible motor from the heat flux coming from the pump casing through an electric cable. A known pump installation for lifting fluid from a well, containing tubing, a downhole pump, a submersible motor, on the housing of which a tube with holes is installed, one end of the tube communicating with the pump “out” and the other plugged [8. SU 5 688607, E21 B 43/00, 1979].

 The disadvantage of this installation is the ineffective cooling of the submersible motor, namely the current lead, ignoring the process of penetration of heat into the current lead, which is due to turbulence of the reservoir fluid in the area of the motor suspension with trickles of fluid from the pump “pump” that are injected through holes in the tube and having passed through pump overheating by 17-20 ° C relative to the initial temperature of the reservoir fluid. As a result of this, the effect of turbulization cannot be significant, since heat transfer occurs from the motor housing to a liquid with an elevated temperature - a formation mixture

15 liquids and superheated liquids with a pump discharge. A disadvantage of the installation is also a reduced efficiency, since part of the pumped liquid that is returned from the pump discharge back to the motor suspension zone, which, due to constrained conditions in the space between the motor housing and the internal

20 of the wall of the production casing, the mixture supplied from the pump discharge does not reach the submersible motor.

 Known borehole pumping unit, including a pump, a drive motor having a housing, clamping elements used for its eccentric placement in the casing of the well. On the case

25 of the electric motor from the side opposite to the location of the clamping elements, a patch element of a material with high thermal conductivity of a solid cross section is fixed, the inner contour of which is made covering part of the perimeter of the motor casing, and the outer one is formed by a part of a circle with a radius equal to the inner radius of the casing of the well at the location electric motor [9.

 SU 1710847, E21 B 47/00, 1992].

The main disadvantage of this pump installation is low operational reliability due to the impossibility of efficient cooling of the motor current lead. This is because the design is not provides satisfactory thermal contact of the patch element with the casing, for example, due to contamination of their surfaces. The consequent presence of high thermal resistances in the contact zones worsens the heat removal from the engine to the string, which ultimately leads to the failure of the electric motor due to overheating and to a decrease in the life of the well installation as a whole. In this case, the process of the influence of high temperature on the motor current lead is simply ignored.

 Known borehole pumping unit, which contains a pump, a drive motor and a heat-conducting element that interacts with the electric motor to remove heat. To increase the reliability of the downhole pump installation due to the intensification of cooling of the submersible motor, the installation is equipped with an oil-filled chamber, which is connected to the base of the electric motor and communicates with it through the central pipe installed in it and the radial clearance between the pipe and the chamber wall. The heat-conducting element is made in the form of a set of heat pipes in the form of disks with an axial hole covering the inner contour of the oil-filled chamber. The outer diameter of the oil-filled chamber is less than the diameter of the electric motor, and the outer diameter of the heat pipes does not exceed the diameter of the electric motor [RU 2298694 F04D13 / 10 F04D29 / 58, publ. 05/10/2007].

 The disadvantages of this installation is the complexity and cumbersome design.

Known submersible pump unit with a forced cooling system of a driving submersible oil-filled electric motor. To increase the reliability of the pump unit due to the efficient operation of the cooling system of the forced-cooling drive motor at the time the well is put into operation, the submersible pump unit contains a pump, a gas separator and a drive motor located in the forced-flow casing with holes on the side surface. The centrifugal gas separator is equipped with an additional screw unit after the separating unit (in the direction of the liquid), and the inlet part of the gas separation channel for removing the gas-liquid mixture is formed by a cavity with an additional screw unit. The design of the casing is made with the possibility of providing a flow of fluid pumped from the annular space, through the side openings of the casing to the inlet openings of the gas separator [11. RU 2293217, F04D13 / 10 F04D29 / 58, publ. 02/10/2007].

 The disadvantage of this unit is the low efficiency of the centrifugal gas separator and the low gas feed rate into the annulus 5 space, since it is known that the separation coefficient is not more than 15% [1. Gareev A.A. Calculation of gas separation coefficient at the pump intake. M. w. Oil industry, 2013. Ns 3, p. 82 - 85]. A significant drawback of this unit is the lack of thermal protection of the current lead and therefore this method of cooling the motor does not find practical application.

 A submersible electric pump is known, comprising a submersible electric motor driven by a pumped liquid, a pump assembly, a forced cooling casing (cooling capacity) with holes on its side and end surfaces, an electric motor

15 located inside the casing. During operation of the electric pump, the pumped liquid through the inlet openings of the forced cooling casing rises to the upper part of the casing, washes the surface of the electric motor and cools it. One of the main reasons for overheating of a submersible motor and its failure in such a design (if any

20 gas separator at the inlet of the pump) the extremely inefficient operation of the cooling system when putting the well into operation. It has been experimentally shown that if there is a gas separator module at the pump inlet, the normal mode of well fluid circulation in the casing is violated and there is no inflow of pumped liquid into the casing inlet openings - the pump “receives from above” [12. RU

25 2136970 C1 (ANK Bashneft), 09/10/1999] and there is no fluid movement near the engine [1]. This method completely ignores the thermal state of the current input and in practice does not affect the overhaul period of the installation of the electric centrifugal pump.

Known submersible electric centrifugal pump installation with submersible centrifugal electric pumps, which to increase the overhaul period of the equipment by more efficient cooling of all heated parts of the submersible electric centrifugal pump installation with an upward flow of liquid contains an electric motor cooled by the pumped liquid, and a centrifugal pump with a receiving mesh and completely placed inside the casing with an annular gap. The valve assembly, wire-frame filter and drive are sequentially attached to the casing from below. The casing on top is attached to the tubing string. The wire-frame filter is represented by a supporting rod, a tube frame and a filter shell, the tube frame having longitudinal slots, and a triangular thread is cut on its outer surface. The filter shell is made of a triangular profile wire, between the turns of which there are slots expanding inside the structure. The invention is aimed at increasing the overhaul period of equipment operation, more efficient cooling of all heated parts of a submersible electric centrifugal pump installation with an upward flow of liquid, which is subjected to preliminary cleaning before this [13. RU 2382237, F04D13 / 10 F04D29 / 58 F04D29 / 70, publ. 02/20/2010].

 In these borehole pumping units, the cooling process of the submersible motor is intensified, but the complexity of manufacturing the installation and its overall dimensions are increased, and the possibility of overheating of the motor in the current lead through copper conductors and lead armor of the cable extension is not prevented.

 In addition, the casing fills with gas over time and ceases to work as a cooling pump unit due to the extremely low value of the coefficient of thermal conductivity of associated gas.

 Known borehole cable with thermally conductive polymer composites for the transmission of electricity in submersible pumps. To protect against cable overheating around the conductors, it is proposed to use a multilayer insulator with increased thermal conductivity, due to the use of layers of ceramic materials that provide improved heat dissipation [14. US 8143523B2, H01 VZ / 44; H01 B7 / 00 publ. 05/27/2012].

The disadvantage of this method is the need to create and use composite materials with desired properties and the subsequent formation of an insulating shell around the protected conductors. However, due to the constant environment of both the pump and the cable extension with a gas layer, in this case, the heating of copper conductors and heat-conducting polymer composites of the cable extension is heated, which increases the heat flux towards the current lead and leads to accelerated melting of solders on the current lead.

 Known power cable for high-temperature environments, in which to ensure cable operation at high temperatures it is proposed to use a metal sheath around each conductor with an insulating coating [15. US 81 13273B2, E21B43 / 00; F04B17 / 03; N01VZ / 44; H01V9 / 02, publ. 02/14/2012].

 The disadvantage of this thermal cable protection is the need for additional technological operations to protect the cable from conductors with an insulating coating, as well as the use of additional material (for example, stainless or carbon steel, monel-metal, etc.) along the entire cable length. However, this increases the rate of heat transfer to the current input of the electric motor and the failure of the electric motor due to the melting of the solder on the windings.

A protector is known for protecting a power cable in a well from mechanical damage, comprising a housing made integrally with a cable channel and with a central channel the size of the outer diameter of the tubing for fixing the tread housing to the sleeve connection. One end of the folding arcuate clamping brackets is made with a loop-shaped end rotatably on an axis that passes through the loop-shaped bracket. The second end is bolted to the body. The tread case is stamped, equipped with two guide ribs, groove amplifiers and groove guards. It is also equipped with guide elements for cable entry and exit from the cable channel of the housing, with the help of which the necessary clearance b is established between the tubing, depending on the thickness of the cable used. The folding arcuate clamping brackets are double-layered, and the ends of the brackets are attached to each other by a T-shaped connection from the inside and directed towards the tubing. The fixing bolt is equipped with a protective cover. The tread case is cast, equipped with four guide ribs and groove guards, as well as cable entry and exit guide elements from the cable channel of the housing [16. RU 2498041 E21 B17 / 10 publ. 11/10/2013]. In this case, the tread made of metal with good thermal conductivity only contributes to the penetration of the heat flux into the current lead and contributes to the fastest engine failure due to the melting of the solder on the windings

 A protector for protecting a power cable in a well is known for protecting a power cable of a pump from mechanical damage during the descent-lifting of the suspension of tubing in vertical, directional and horizontal wells, which comprises a housing made integrally with the cable channel and the central channel with the size of the outer diameter of the tubing, folding arched clamping brackets, one end of which is made with a loop-shaped end with the possibility of rotation on an axis that passes dit bracket via a loop. The tread case on both sides is equipped with grooves with closed contours. On the one hand, loops are fixed in the grooves, which, through the axis, are mated with loop-shaped staples. Opposite locking grooves are made with bent petals of the body from the side of the tread axis and directed towards the cable channel. The second ends of the arcuate clamping brackets have grooves and are made in a U-shape, which when assembled, the tread engages with the locking grooves and are fixed from possible separation by the bent petals of the housing. The design is simplified, the assembly time, disassembly is reduced [17. RU 2432448 E21 B17 / 10 publ. 10.27.2011].

 This method is used to protect against mechanical damage and does not eliminate the contact heat exchange of the cable extension and the heated pump housing.

A protector for protecting a power cable in a well is known, characterized in that it comprises a housing with clamping clamps, which are pivotally connected to the housing on one side, a cable channel formed inside the housing, while the other side of the coupling clamps is connected to the housing by means of fasteners, and in the housing and / or holes are made in the tread collars. A beveled protrusion is made on one of the outer sides of the coupling half, a fixing element is located in the cable channel, which is capable of pressing a power cable to it, the fixing element is a leaf spring, and the housing and half clamps are made of low carbon steel by casting [18. RU 94621 E21 B17 / 10 Publ. 05/27/2010].

 This method does not guarantee deformation of the cable line during tripping and preventing contact heat exchange between the cable extension and the heated pump casing.

 A device for protecting a power cable in a well is known, comprising a housing in the form of a sleeve covering a coupling of tubing, on the outer surface of which grooves are made for laying a power cable, and fastening elements of the housing to the tubing coupling, characterized in that the housing of the device is composed of two parts (left and right half-shells), each of which has the form of brackets, with the formation of two stops in the body cavity, the distance between which in the assembly is equal to the length of the coupling, while on the outer surfaces of the left and right floor of the hulls, ribs are made, forming a single groove in the assembly with a depth exceeding the cable thickness, for laying the cable with a guaranteed gap and eliminating the possibility of relative rotational displacement of the half-shells on adjacent edges of the ribs, a hook is made in the form of an annular groove and an annular protrusion in the edges of the left and right half-shells and the opposite ends of the ribs are made with a bevel [19. RU 62645 E21 B17 / 10 Publ. 04/27/2007].

 Known from the prior art, protectors for protecting a power electric cable in a well provide its protection only from mechanical damage, but do not protect it from overheating from the submersible pump housing.

The closest in technical essence and achieved technical result (prototype) is a device developed earlier by the author that eliminates overheating of the power supply cable of the electric centrifugal pump (ESP) installation from the casing of the first section of the ESP pump, consisting of heat-insulating linings in the form of a parallelepiped of a certain thickness, depending on the sizes of the ESP having recesses of a cylindrical shape with opposite faces of the parallelepiped, one with a radius of at least the radius of the outer cylindrical surface ited ESP pump for a snug fit to the outer cylindrical surface of the pump ESP another in shape and size cross-sectional ESP power cable for laying supply cable ESP precluding its movement to a plane perpendicular to the length of the linings, and fastening belts intended for fastening the power cable of the ESP together with the pads to the outer cylindrical surface of the ESP pump [21. RU 91390 F04D29 / 58 publ. 02/10/2010 (prototype)].

 5 The disadvantages of the prototype device is the ability to drop heat-insulating linings during operation of the device in the well, the possibility of contact of the cable line with the pump housing in the absence of heat-insulating linings when the cable is deformed, the need for a large number of heat-insulating linings and a large area of contact of the linings with the pump body, which ultimately leads to the transfer of heat through the copper cores of the cable to the submersible motor, causes the heating of the solder spots honey stator conductors and when the solder melting temperature is exceeded, a violation of the electrical conductivity in the electric motor and the failure of the entire installation

15 electric centrifugal pump.

 Common disadvantages of the power cable protection devices known from the prior art are the neglect of “heat generation” in pumps and the heat distribution features in the electric cable and in the installation units of the electric centrifugal pump, filling features

20 of the borehole space with the borehole fluid from the pump intake to the bed with clean oil, the dependence of gas content on the pressure at the pump intake, the dependence of the saturation pressure of the borehole liquid with gas on temperature, as well as low-tech installation and operation, and most importantly, neglect of the laws of heat engineering and heat transfer during formation,

25 the distribution and penetration of heat through the cable line into the current lead of the submersible motor.

 Task and technical result

The objective and technical result of the invention is to prevent overheating of the electric cable and thermal protection of the submersible electric motor by preventing overheating of the electric cable of the submersible electric motor of the installation of the electric centrifugal pump from heat flow through the supply electric cable passing along the pump casing, which is heated when pumping highly carbonated liquids by the electric centrifugal pump , and ultimately as a result, an increase in the overhaul period of the operation of the electric centrifugal pump installation, an increase in the efficiency of the operation of the electric centrifugal pump installation and a reduction in the loss of oil production during its production from deep and superdeep wells.

 Disclosure of invention

 The problem is solved and the technical result is achieved by the fact that the electric cable for the submersible motor of the installation of an electric centrifugal pump for an oil well, comprising an electric centrifugal pump coupled to each other and a submersible motor with an electric cable adjacent to the pump housing, according to the invention comprises supports attached to it made with the ability to fix the position of the electric cable relative to the pump casing with a gap between the pump casing and the electric cable and with the possibility of circulating the borehole fluid in the gap between the pump casing and the electric cable.

 Moreover, in various possible variants of the design of the electric cable for the submersible electric motor of the installation of an electric centrifugal pump for an oil well:

 the supports are made of a material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass;

 supports on the side of the pump housing are covered with heat-insulating or heat-reflecting material;

 the ends of the supports in places of their contact with the pump casing are made with the possibility of contacting a small area with the pump casing;

 supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable;

 the supports are made located at the corners of at least one plate attached to the sheath of the electric cable and made in the form of bent corners of the plate;

the supports are attached to the electric cable by means of at least one bracket made with the possibility of fixing the bracket to an electric cable by compressing the edges of the bracket with plastic deformation or by connecting the edges of the bracket covering the electric cable; the supports are attached to the electric cable by means of at least one bracket made of impact-resistant corrosion-resistant material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials;

 the supports are made of impact-resistant, corrosion-resistant material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass;

 the supports are made in the form of bent parts of at least one bracket, made with the possibility of its attachment to the electric cable by pressing the edges of the bracket by plastic deformation or by connecting the edges of the bracket covering the electric cable or

 the supports are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one bracket with the formation of rectangular, rounded or pointed supports directed towards the pump casing with a small contact area of the supports with the pump casing.

 The problem is solved and the technical result is also achieved by the fact that in the thermal protection device of a submersible electric motor of an electric centrifugal pump installation for an oil well, comprising an electric centrifugal pump coupled to each other and an electric submersible motor with an electric cable adjacent to the pump casing, according to the invention is made in the form located between the casing pump and electric cable supports, made with the possibility of fixing the position of the electric cable relative to pump housing with a gap between the pump casing and the electric cable and with the possibility of circulating well fluid in the gap between the pump casing and the electric cable.

Moreover, in various possible variants of the design of the thermal protection of the submersible electric motor of the installation of an electric centrifugal pump for an oil well: the supports are made of a material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass;

 supports on the side located to the pump body are covered with 5 heat-insulating or heat-reflecting material;

 the ends of the supports in places of their contact with the pump casing are made with the possibility of contacting a small area with the pump casing;

 supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable;

 the supports are made located at the corners of at least one plate attached to the sheath of the electric cable and are made in the form of bent corners of the plate;

 the supports are attached to the electric cable by means of at least 15 brackets made with the possibility of fastening the brackets to the electric cable by compressing the edges of the bracket with plastic deformation or by connecting the edges of the bracket covering the electric cable; the supports are attached to the electric cable by means of at least one bracket made of impact-resistant, corrosion-resistant 20 material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials;

 the supports are made in the form of bent parts of at least one bracket, made with the possibility of its attachment to the electric cable by pressing the edges of the bracket by plastic deformation or by connecting 25 the edges of the bracket covering the electric cable;

 the supports are made of impact-resistant, corrosion-resistant material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass or.

the supports attached to the electric cable are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one bracket with the formation of supports of a rectangular, round or pointed shape, directed by the ends to the pump casing with a small contact area of the supports with the pump casing. The problem is solved and the technical result is also achieved by the fact that the installation of an electric centrifugal pump for an oil well, comprising interconnected electric centrifugal pump and a submersible motor with an electric motor adjacent to the pump casing

5 with a cable, according to the invention, comprises a thermal protection device for a submersible electric motor made in the form of supports located between the pump housing and the electric cable, which are capable of fixing the position of the electric cable relative to the pump housing with a gap between the pump housing and the electric cable and allowing borehole fluid to circulate in the gap between the pump housing and the electric cable.

 Moreover, in various possible variants of the design of the installation of an electric centrifugal pump for an oil well, the supports are made of material with a low coefficient of thermal conductivity,

15, for example, of ceramic, plastic, composite material, porcelain or glass;

 supports on the side of the pump housing are covered with heat-insulating or heat-reflecting material;

 the ends of the supports in places of their contact with the pump casing are made with 20 the possibility of contact with a small area with the pump casing;

 supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable;

 the supports are made located at the corners of at least one plate attached to the sheath 25 of the electric cable and are made in the form of bent corners of the plate;

 the supports are attached to the electric cable by means of at least one bracket made to fasten the bracket to the electric cable by compressing the edges of the bracket with plastic deformation or by connecting the edges of the bracket covering the electrical cable;

the supports are attached to the electric cable by means of at least one bracket made of impact-resistant corrosion-resistant material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials; the supports are made in the form of bent parts of at least one bracket, made with the possibility of its attachment to the electric cable by pressing the edges of the bracket by plastic deformation or by connecting the edges of the bracket covering the electric cable;

 5 supports are made of impact-resistant, corrosion-resistant material with a low coefficient of thermal conductivity, for example, of ceramics, plastic, composite material, porcelain or glass;

 The supports are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one bracket with the formation of rectangular, rounded or pointed supports, with their ends directed to the pump casing with a small contact area of the supports with the pump casing.

 The problem is solved and the technical result is also achieved by the fact that to implement the method of thermal protection of the submersible

15 of the electric motor of the installation of an electric centrifugal pump for an oil well containing a pump, a submersible motor with a supply cable and means of thermal protection of the submersible motor, according to the invention, the means of thermal protection of the submersible motor are made in the form in the form located between the pump casing and

20 electric cable supports made with the possibility of fixing the position of the electric cable relative to the pump casing with a gap between the pump casing and the electric cable and allowing circulation of the borehole fluid in the gap between the pump casing and the electric cable.

 25 In this case, an electric cable of the above construction is used, a thermal protection device of the submersible electric motor of the construction described above is used, or an electric centrifugal pump installation is used for an oil well of the construction described above.

 Brief Description of the Drawings

In the structurally preferred, described in this application, but not the only mandatory options, the features of the structural design of the claimed devices and method are shown.

In FIG. 1 shows a General view of the installation of the electric centrifugal pump of an oil well, which shows a submersible motor 1 with current lead 10, hydraulic protection 2, centrifugal pump 3 with inlet openings 8, tubing string 4, electric cable 5, metal belts 6 for attaching the electric cable to the tubing 4 and the centrifugal pump, thermal protectors 7 with supports 9.

 In FIG. 2 shows a front view A of the electric cable 5 from the side of the centrifugal pump, which shows thermal protection in the form of brackets 7 attached to the electric cable 5 with supports 9.

 In FIG. 3 is a section A view showing an electric cable 5 with copper conductors 1 1 and thermal protection means attached to the electric cable 5 in the form of brackets 7 with supports 9.

 In FIG. 4 is a side view of a thermal protective device attached to an electric cable 5 in the form of a bracket 7 with supports 9.

 In FIG. 5 is a top view of a thermal protection means in the form of a bracket 7 with supports 9.

 In FIG. 6 is a side view of a thermal protective device in the form of a bracket 7 with supports 9.

 In FIG. 7 is a cross section of an electric cable 5 with copper conductors 1 1 and heat protection means attached to the electric cable 5 in the form of a plate with supports 9.

 The implementation of the invention

When operating electric centrifugal pump installations (ESPs) in deep, superdeep oil wells - with a depth of up to 3 thousand meters vertically and a high gas content (up to 250 - 500 m ³ / m ³ ), the pump and the power supply cable adjacent to the pump often overheat, which leads to the failure of the ESP due to an unacceptable change in the electrical resistance of the "electric cable-motor" system.

 It is known that the failure of an electric centrifugal pump installation by a submersible electric motor is 22.1% due to a failure of the electric centrifugal pump installation [20].

The use of the proposed devices and method of thermal protection of a submersible motor in the installation of an electric centrifugal pump by means of brackets with heat-insulating supports or heat-insulating supports attached to an electric cable prevents contact heat exchange between the pump casing and the electric cable, preventing heat from spreading through the copper cores of the electric cable to the side of the submersible motor, which provides thermal protection of the submersible motor from overheating.

 In addition, fixing the position of the electric cable relative to the pump casing with a gap between the pump casing and the electric cable allows the circulation of borehole fluid in the gap between the pump casing and the electric cable, which helps to cool the pump casing and electric cable with circulating unheated borehole fluid.

 As shown by field tests of the present invention, this task is confidently solved and the required technical result is achieved - overheating of the submersible electric motor, namely its current supply, is prevented from the heat flux passing through the supply electric cable passing along the pump casing, which overheats when pumping highly carbonated pump liquids, which ultimately allows you to increase the overhaul period of the installation of the electric centrifugal pump , increase the efficiency of the installation of the electric centrifugal pump installation and reduce the loss of oil production during its production from deep and superdeep wells.

 Installation of an electric centrifugal pump (Fig. 1) consists of a submersible motor 1 with a current lead 10, to which a hydroprotection 2 is connected, and then a centrifugal pump 3 with receiving holes 8.

 The installation of an electric centrifugal pump is connected to the string of tubing 4, through which the well fluid entering the pump through the inlet openings 8 is compressed under pressure to feed it to the earth's surface - to the collection point. Installation of an electric centrifugal pump is powered by an electric current supplied to the submersible motor 1 by a supply electric cable 5.

The power cable 5 with metal belts 6 is attached to the tubing string 4, then to the pump casing and connected to the submersible motor through a sleeve connection - current lead 10, in which the copper cores of the power cable are soldered to the wires of the motor windings. During operation, the centrifugal pump 3 heats up and heat from the pump housing, through contact heat transfer, is transferred to the supply electric cable 5 and through copper cores 1 1 of the supply electric cable 5 penetrates the current lead 10 of the submersible motor and disables it 5 as a result of melting of the solder in soldering copper conductors 1 1 electric cable 5 to the ends of the windings of a submersible motor.

 This is due to the fact that the pump, when pumping highly carbonated wellbore fluid, can be heated up to more than 300 ° С, the power supply cable is usually made of heat-resistant material (with lead armor), with an operating temperature of up to 230 ° С, the maximum permissible temperature of the submersible motor is equal to the solder melting temperature 180 ° C, and the rated operating temperature of the submersible motor is 130 ° C.

 When the temperature of the submersible motor rises above 180 ° C

15 the ends of the windings of the submersible electric motor soldered to the copper conductors 11 of the electric cable 5 in the current lead 10 are unsoldered (destroyed), a short circuit occurs and the submersible electric motor of the installation of the electric centrifugal pump fails.

 To provide thermal protection for the current input of the submersible motor

20 from overheating and reducing the number of failures of the installation of the electric centrifugal pump due to failure of the motor windings, it is proposed that the technically simple but effective means of thermal protection proposed change the mechanism of the distribution of heat generated in a centrifugal pump and provide

25 cooling the pump and electric cable with circulating unheated well fluid and thereby provide thermal protection for the current input of the submersible motor and prevent its failure due to overheating.

To this end, it is proposed to install heat-insulated supports 9 (Fig. 1-5) between the centrifugal pump 3 adjacent to the centrifugal pump housing 3 from the side of the pump housing, providing fixation of the position of the electric cable 5 relative to the pump housing with a gap between the pump housing and the electric cable, as well as providing the possibility of circulation of unheated well fluid in the gap between the pump casing and the electric cable.

 In this case, the contact area of the supply cable 5 with the heated surface of the centrifugal pump 3 decreases many times, therefore, the heat flux decreases in the same direction as the cable line, and the circulation of the borehole fluid in the gap between the electric cable and the pump casing provides additional cooling.

 In FIG. 1-7 show possible options for the proposed thermal protection devices, possible structural options for connecting to the supply electric cable 5 brackets 7 with heat-insulating supports 9 or heat-insulating supports 9 and their design.

 Each bracket 7 or directly an electric cable with a width sufficient to fix the position of the supply cable is provided with supports 9 made of heat-insulating material or with heat-insulating nozzles or gaskets at the ends of the supports 9 or with a small area of the ends of the supports.

 The thermal protection of the electric cable and, accordingly, the submersible motor is achieved not only by a small contact area of the ends of the supports 9 with the surface of the pump casing 3, or by the use of heat-insulating material or heat-insulating nozzles or gaskets at the ends of the supports 9 in places of their contact with the pump casing 3, but also by providing the possibility of circulating well fluid in the gap between the electric cable 5 and the pump casing 3.

 The distance between the supports 9 is chosen so that the deformation of the supply cable is prevented when the pump hits the internal walls of the production well during downs-ups and operation of the pump in the well.

 The supports 9 fix the position of the supply cable 5 at a certain distance from the pump casing 3 with a gap, thereby effectively preventing the transfer of heat from the pump casing 3 to the supply electric cable 5 and allowing circulation of unheated well fluid in the gap between the electric cable 5 and the pump casing 3.

The supports 9 can be made of heat-insulating plastic, glass, porcelain, ceramics and attached to brackets or directly to electric cable in various known ways or can be made by stamping and bending certain parts of the brackets.

 In FIG. 4 - 7 illustrate possible manufacturing options for staples 7 with stamped stops.

 5 It is advisable to carry out the ends of the supports with a small area of contact with the pump housing, in order to reduce contact heat transfer between the pump housing 3 and the power supply cable 5.

 The material for the brackets 7 can serve as a stainless steel metal tape, heat-resistant and impact-resistant grades of plastic or composite chemically inert materials, providing the possibility of finding the brackets in an aggressive environment.

 The brackets 7 can be made by stamping a metal strip of stainless steel so that the stamped ends of the supports 9, touching the pump casing 3, have the smallest possible contact area with the pump casing 15 to slow down the contact heat exchange between the pump casing 3 and the power supply cable 5 (Fig. 4-7).

 The brackets 7 perform the function of fastening the supports 9 made of heat-conducting material or containing nozzles or gaskets of heat-insulating material and serve to fasten the supports for a long time 20 and fix the position of the power supply cable at a certain distance from the pump housing, and also the brackets 7 keep the supports from mechanical damage during hoisting operations by evenly distributing the load among the supports.

 Supports 9 serve to prevent contact heat transfer 25 of the surface of the pump 3 and the supply cable 5, can be attached to the brackets 7 by stamping, gluing or pasting into the holes on the surface of the brackets.

 The supports 9 perform the function of fixing the position of the supply electric cable 5 at a certain distance from the pump casing 5 and to prevent deformation of the supply electric cable 5 during tripping in the well.

Supports 9 can be made of brackets, glass, porcelain, ceramics, plastics, composite corrosion-resistant, heat-insulating and durable materials. As a possible design options for the individual elements of the electric cable with thermal protection, thermal protection devices and installation of an electric centrifugal pump with thermal protection of the submersible electric motor, various well-known and 5 traditional for the oil industry technologies, materials and design solutions commonly used in the oil industry can be used.

 A detailed description of the design features of the claimed devices and the thermal protection method shows a causal relationship between the essential features and the technical result, and shows a confident solution to the problem and achieving the desired technical result, namely, the implementation of the present invention allows thermal protection of the submersible motor of the installation of an electric centrifugal pump for oil wells, prevent overheating of the submersible motor from heat eye, walking on the supply

15 cable running along the pump casing, which is heated when pumping highly carbonated liquids, and to increase the overhaul period of the installation of the electric centrifugal pump for oil production by, which ultimately eliminates the loss of oil production and errors of the management personnel.

 20 Given the novelty of the set of essential features, the technical solution of the task, the inventive step and the materiality of all general and particular features of the invention, proven in the section "Prior Art" and "Disclosure of the invention", proven in the section "Implementation of the invention" technical feasibility and industrial applicability

25 inventions, the confident solution of the inventive tasks and the achievement of the required technical result when implementing and using the invention, in our opinion, the claimed group of inventions satisfies all the eligibility requirements for inventions.

zo. The analysis also shows that all the general and particular features of the invention are essential, since each of them is necessary, and together they are not only sufficient to achieve the purpose of the invention, but also make it possible to realize the invention in an industrial way. In addition, the analysis of the set of essential features of the invention and the uniform technical result achieved through their use shows the existence of a single inventive concept, close and inextricable connection between the objects of the invention, which allows combining the invention in one application, that is, to ensure the requirements of the criterion of unity of invention.

Claims

Electric cable, thermal protection device for a submersible electric motor, installation of an electric centrifugal pump for an oil well with thermal protection of a submersible electric motor, and a method for thermal protection of a submersible electric motor  electric centrifugal pump  (Claim) 10 1. An electric cable for a submersible electric motor for installing an electric centrifugal pump for an oil well, comprising an interconnected electric centrifugal pump and an electric submersible motor with an electric cable adjacent to the pump casing with means for fixing the position of the electric cable relative to the pump casing 15, characterized in that the electric cable contains attached supports to it, made with the possibility of fixing the position of the electric cable relative to the pump casing with a gap between the pump casing and the electric cable and with the possibility of circulating the well fluid in the gap between the pump casing and the electric cable, with 20 ends of the supports in places of their contact with the pump casing made with the possibility of contacting a small area with the pump casing.  2. An electric cable according to claim 1, characterized in that the supports are made of a material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or 25 glasses.  3. An electric cable according to claim 1, characterized in that the supports on the side located to the pump housing are coated with heat-insulating or heat-reflecting material.  4. The electric cable according to claim 1, characterized in that the supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable. 5. An electric cable according to claim 1, characterized in that the supports are arranged at the corners attached to the sheath electrical cable of at least one plate and made in the form of bent corners of the plate.  6. The electric cable according to claim 1, characterized in that the supports are attached to the electric cable by at least one 5 staples, made with the possibility of fastening the staples to the electric cable by pressing the edges of the staples by plastic deformation or by connecting the edges of the staple enclosing the electric cable.  7. The electric cable according to claim 1, characterized in that the supports are attached to the electric cable by means of at least one bracket made of impact-resistant corrosion-resistant material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials.  8. Electric cable according to any one of p. 8 or p. 9, characterized in that the supports are made of impact-resistant, corrosion-resistant material with a low 15 coefficient of thermal conductivity, for example, of ceramics, plastic, composite material, porcelain or glass.  8. An electric cable according to claim 1, characterized in that the supports are made in the form of bent parts of at least one bracket made with the possibility of its attachment to an electric cable 20 by compressing the edges of the bracket with plastic deformation or by joining the edges of the bracket covering the electric cable.  9. The electric cable according to claim 1, characterized in that the supports attached to the electric cable are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one 25 staples with the formation of supports of a rectangular, rounded or pointed shape, directed by the ends to the pump casing with a small area of contact of the supports with the pump casing. 10. Thermal protection device for a submersible electric motor of an installation for an electric centrifugal pump for an oil well, comprising an electric centrifugal pump coupled to each other and a submersible motor with an electric cable adjacent to the pump casing, characterized in that it is made in the form of supports arranged between the pump casing and the electric cable lockable the position of the electric cable relative to the pump casing with a gap between the pump casing and the electric cable and allowing the circulation of the borehole fluid in the gap between the pump casing and the electric cable, and the ends of the supports in places of contact with the 5 pump casing are made with the possibility of contacting a small area with the pump casing .  1 1. Thermal protection device for a submersible electric motor according to claim 10, characterized in that the supports are made of a material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass.  12. The thermal protection device of a submersible electric motor according to claim 10, characterized in that the supports on the side located to the pump housing are coated with heat-insulating or heat-reflecting material.  13. The thermal protection device of a submersible motor according to 10, 15, characterized in that the supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable.  14. The thermal protection device of a submersible motor according to 1 1, characterized in that the supports are located at the corners 20 attached to the sheath of the electric cable of at least one plate and made in the form of bent corners of the plate.  15. The thermal protection device of a submersible electric motor according to 10. characterized in that the supports are attached to the electric cable by means of at least one bracket made with the possibility of 25 securing the brackets to the electric cable by compressing the edges of the brackets with plastic deformation or by connecting the edges of the brackets enclosing the electric cable. 16. The thermal protection device of a submersible electric motor according to claim 10, characterized in that the supports are attached to the electric cable by at least one bracket made of impact-resistant corrosion-resistant material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials. 17. Thermal protection device for a submersible electric motor according to claim 10, characterized in that the supports are made in the form of bent parts of at least one bracket made with the possibility of its attachment to an electric cable by pressing the edges with plastic deformation 5 staples or by connecting the edges of the staple covering the electric cable.  18. The thermal protection device according to any one of p. 16 or p. 17, characterized in that the supports are made of impact-resistant, corrosion-resistant material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or 10 glass.  19. Thermal protection device for a submersible electric motor according to claim 10, characterized in that the supports attached to the electric cable are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one bracket to form supports 15 rectangular, rounded or pointed shape, directed by the ends to the pump casing with a small area of contact of the supports with the pump casing. 20. Installing an electric centrifugal pump for an oil well, comprising interconnected electric centrifugal pump and 20 submersible motor with an electric cable adjacent to the pump casing, characterized in that it comprises a thermal protection device for the submersible electric motor made in the form of supports located between the pump casing and the electric cable, with the possibility of fixing the position of the electric cable relative to the pump casing with 25 by the gap between the pump housing and the electric cable and with the possibility of circulating well fluid in the gap between the pump housing and the electric cable, the ends of the supports in places of contact with the pump housing being made with the possibility of contacting a small area with the pump housing .. zo 21. Installation of an electric centrifugal pump for an oil well in 20, characterized in that the supports are made of a material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass. 22. Installation of an electric centrifugal pump for an oil well according to claim 20, characterized in that the supports on the side of the pump housing are coated with heat-insulating or heat-reflecting material.  23. Installation of an electric centrifugal pump for an oil well of 5 to 20, characterized in that the supports are attached to the electric cable by soldering, welding, screwing or gluing the supports to the sheath of the electric cable.  24. Installation of an electric centrifugal pump for an oil well according to claim 20, characterized in that the supports are arranged at the corners of at least one plate attached to the sheath of the electric cable and are made in the form of bent corners of the plate.  25. Installation of an electric centrifugal pump for an oil well according to claim 20, characterized in that the supports are attached to the electric cable by means of at least one bracket made with the possibility of 15 securing the brackets to the electric cable by compressing the edges of the bracket by plastic deformation or by joining the edges of the bracket covering the electric cable.  26. Installation of an electric centrifugal pump for an oil well of 20, characterized in that the supports are attached to an electric cable 20 by means of at least one bracket made of impact-resistant, corrosion-resistant material, for example, stainless steel, stainless alloys, heat-resistant and impact-resistant plastics or composite materials.  27. Installation of an electric centrifugal pump for an oil well of 25 to 20, characterized in that the supports are made in the form of bent parts of at least one bracket, made with the possibility of its attachment to the electric cable by pressing the edges of the bracket by plastic deformation or by connecting the edges of the bracket covering the electric cable . 28. Installation of an electric centrifugal pump for an oil well according to any one of p. 26 or p. 27, characterized in that the supports are made of impact-resistant, corrosion-resistant material with a low coefficient of thermal conductivity, for example, ceramic, plastic, composite material, porcelain or glass. 29. Installation of an electric centrifugal pump for an oil well according to claim 20, characterized in that the supports attached to the electric cable are made in the form of cut out and bent rectangular, rounded or acute-angled parts of at least one bracket with the formation of rectangular, rounded or pointed supports directed to the ends pump housing with a small contact area of supports with the pump housing. 30. A method of thermal protection of a submersible electric motor of an electric centrifugal pump installation for an oil well comprising a pump, a submersible electric motor with a power cable and means of thermal protection of a submersible electric motor, characterized in that the thermal protection of the submersible electric motor is made in the form located between the pump body and the electric cable supports made with the possibility of fixing the position of the electric cable relative to the pump casing with a gap between the pump casing and electric with a tricycle cable and with the possibility of circulating well fluid in the gap between the pump casing and the electric cable with a small contact area between the supports and the pump casing.  31. The method of thermal protection of a submersible motor for installing an electric centrifugal pump for an oil well according to claim 35, characterized in that an electric cable is used according to any one of claims 1 to 9.  32. The method of thermal protection of a submersible electric motor of an electric centrifugal pump installation for an oil well according to claim 35, characterized in that a thermal protection device of a submersible electric motor according to any one of claims 10 to 19 is used.  33. The method of thermal protection of a submersible motor for installing an electric centrifugal pump for an oil well according to claim 35, characterized in that the installation of an electric centrifugal pump for an oil well according to any one of claims 20 to 29