Termination device for load-bearing heating cable

Abstract

This utility model relates to oil production and is designed to equip a load-bearing heating cable used to heat fluid flow within the tubing of oil wells, protecting and sealing the lower end of the cable. The technical result consists of protecting well equipment (bypass valve, downhole pump) in emergency situations involving a possible cable fall. For this purpose, the termination device of the load-bearing heating cable consists of a protective sleeve made of a round pipe and a monolithic end piece welded to the protective sleeve, which houses the end of the cable, consisting of interconnected conductive conductors covered with a common electrical insulating coating. The free cavity of the protective sleeve is filled with a dielectric, heat-resistant sealing material. The device itself is hermetically secured to the outer sheath of the cable.The monolithic end section is detachable for installing removable elements with expanders. 6 pcs., 2 fig.

Description

[0001] The utility model relates to the field of oil production for equipping a heating load-bearing cable used to heat the flow of liquid inside the tubing of oil producing wells to protect and seal the lower end of the cable.

[0002] A termination device for a multi-core heating cable is known, including a protective cup, in one part of the cavity of which the end of the heating cable is placed, consisting of ends of conductive cores, stripped of the insulating layer, rigidly connected to each other to form a closed electric circuit, characterized in that in another part of the cavity of the protective cup a separating sleeve is installed, on the outer or inner surface of one of the ends of which a thread is made for connecting it to the protective cup, while the other end of the sleeve is hermetically connected to the common insulating sheath and / or with the armor of the heating cable, wherein the internal space of the separating sleeve is covered by a transverse partition with openings for passing the conductive cores of the heating cable through them and the number of openings in the transverse partition corresponds to the number of conductive cores of the heating cable,and the diameter of each opening of the transverse partition is equal to the diameter of the conductive core not stripped of the insulating layer, wherein the conductive cores, not stripped of the insulating layer, are introduced into the internal space of the separating sleeve, freed from the common insulating sheath and armour of the heating cable, with their output through the openings of the transverse partition into the cavity of the protective cup, where their ends, stripped of the insulating layer, connected to each other, form a closed electrical circuit, wherein the cavity of the protective cup and the internal space of the separating sleeve are filled with a polymer sealing material, and in the wall of the protective cup there is at least one opening for pouring polymer sealing material into the cavity of the protective cup, wherein the said opening is provided with a plug (Certificate of the Russian Federation for Utility Model No. 39218, cl. H01B 7 / 18, 2004),

[0003] The disadvantage of this device is the low reliability of fastening the protective cup to the cable body, the high probability of depressurization of the protective cup of the device under conditions of high pressure and significant vibrations in the upward flow of well fluid, the complexity of the design and installation of the device, as well as the inability to install protection against damage to the bypass valve and the submersible pump if the cable falls in emergency situations.

[0004] Also known is a universal termination device for a multi-core cable, including a protective cup, in the cavity of which the end of a heating cable is placed, consisting of bare ends of conductive cores connected to each other to form a closed electrical circuit and a common electrical insulating coating applied to these connected ends of the cores, and a sealing partition with holes for passing conductive cores through them is installed, wherein in the wall of the protective cup there is at least one hole provided with a plug, intended for placing in the free cavity of the protective cup a material with dielectric properties, characterized in that from the open end of the protective cup, close to the sealing partition, a pressing-stop element with an opening for passing conductive cores through it is additionally installed, having a threaded connection with the protective cup, and as a material with dielectric properties,the free cavity of the protective cup is filled with a gaseous and / or liquid substance with dielectric properties (Russian Federation Certificate for Utility Model No. 43996, class H01B 7 / 18, 2005),

[0005] However, this device also has a number of drawbacks, namely a complex, multi-part design, multiple threaded connections, and an unreliable mechanical fastening to the cable, which can lead to loss of seal during operation. Furthermore, it is difficult to fill the empty space in the protective sleeve with liquid or gaseous dielectric material through the plug. This device also lacks the ability to install protection against damage to the bypass valve and submersible pump in the event of a cable fall in an emergency.

[0006] The closest to the proposed model is the termination device of a load-bearing geophysical cable for heating wells, including a protective cup, in the cavity of which the end of the cable is placed, consisting of ends of heating current-carrying cores stripped of the insulating layer and connected to each other to form a closed electrical circuit, a metal sleeve pressed onto these cores, a common electrical insulating coating applied to the cores, while the cavity of the protective cup is filled with a dielectric heat-resistant sealing material with a protective cup of a non-detachable design, made in the form of a pipe of a circular cross-section with a wall thickness of 1….2 mm thick, with one end capped by a welded spherical end cap. The inner diameter of the protective sleeve is equal to the outer diameter of the cable, and the outer diameter of the protective sleeve exceeds the cable diameter by no more than 4 mm. The protective sleeve is hermetically secured to the cable's outer sheath using three or more annular grooves rolled onto the sleeve's surface during installation of the termination device. This groove forms a single, monolithic structure with the cable, ensuring a tight and durable connection due to the elastic deformation properties of the outer sheath material and the cable's design features. The protective sleeve can be made of corrosion-resistant steel, and the overall electrical insulation coating applied to the conductive heating conductors can be formed from the cable's intermediate sheath or formed from multiple layers of heat-shrinkable tubing.A pressure sensor and / or a temperature sensor can also be placed in the protective cup (Russian Federation Certificate for Utility Model No. 212167; H01B 7 / 00 (2021.08); H02G 15 / 00 (2021.08).

[0007] The technical result achieved by the proposed model is to ensure the protection of well equipment (bypass valve, submersible pump (ESP)) in emergency situations with a possible cable fall.

[0008] The specified technical result is ensured by a termination device for a load-bearing heating cable, which consists of a protective cup made from a round-section pipe and a monolithic end portion that is connected by a welded joint to the protective cup, in which, in turn, the end of the cable is placed, consisting of interconnected conductive cores covered with a common electrical insulating coating, and the free cavity of the protective cup is filled with a dielectric heat-resistant sealing material, while the device itself is hermetically secured to the outer sheath of the cable using three or more annular grooves rolled onto the surface of the cup.

[0009] The distinctive feature of this design is:

[0010] The end part of the termination device is made disassemblable for installation of a removable element with expanders;

[0011] The removable element is connected to the detachable end part by a threaded connection;

[0012] The removable element is connected to the detachable end part by a pin connection;

[0013] the diameter of the removable element is larger than the diameter of the protective cup and is from 38 mm to 48 mm;

[0014] The expanders are installed on the removable element of the end part by means of a welded connection;

[0015] Expanders are manufactured as a single piece with a removable end element by milling from a monolithic cylindrical blank.

[0016] Fig. 1 shows a general view of the termination device with expanders and a threaded connection of the removable part,

[0017] where

[0018] 1 - Cable,

[0019] 2 - Protective glass,

[0020] 3 - Monolithic end part,

[0021] 4 - Removable element of the monolithic end part,

[0022] 5 - Expanders for removable element of monolithic end part.

[0023] The termination device (Fig. 1) is installed on the cable (pos. 1) and consists of a protective sleeve (pos. 2), which contains the conductive cores, which are connected to each other and covered with a common electrical insulating coating, and the free cavity of the protective sleeve is filled with a dielectric heat-resistant sealing material, while the device itself is hermetically fixed to the outer sheath of the cable. The monolithic end part (pos. 3) is connected to the removable element (pos. 4) by a threaded connection. On the removable element there are expanders (pos. 5) of cylindrical, rectangular or trapezoidal shape, which are connected to the removable element by welded seams or are made as a single product with the removable element by milling.

[0024] Fig. 2 shows a general view of the termination device with expanders and a pin connection of the removable part,

[0025] where

[0026] 1 - Cable,

[0027] 2 - Protective glass,

[0028] 3 - Monolithic end part,

[0029] 4 - Removable element of the monolithic end part,

[0030] 5 - Expanders for the removable end part element,

[0031] 6 - Pin,

[0032] 7 - Protective sleeve.

[0033] The termination device (Fig. 2) is installed on the cable (pos. 1) and consists of a protective cup (pos. 2), which contains the conductive cores, which are connected to each other and covered with a common electrical insulating coating, and the free cavity of the protective cup is filled with a dielectric heat-resistant sealing material, while the device itself is hermetically fixed to the outer sheath of the cable. The monolithic end part (pos. 3) is connected to the removable element (pos. 4) by a pin connection. The removable element is equipped with expanders (pos. 5) of cylindrical, rectangular or trapezoidal shape, which are connected to the removable element by welded seams or are made as a single product with the removable element by milling. The removable element of the end part is fixed using a pin (pos. 6). To prevent the pin from falling out, a protective sleeve (item 7) can be additionally placed on the connection point, which is fixed on the end monolithic part.

[0034] The installation of the termination device on the cable is carried out as follows

[0035] At the free end of the cable pos. 1 (Fig. 1, 2), the conductive cores are stripped and then connected into a closed circuit using an aluminum or copper sleeve. Next, the cores are covered with a common insulating material and a protective cup pos. 2 (Fig. 1, 2) is put on them; the cup is pre-filled 1 / 3 full with a sealing insulating compound. After that, the protective cup is fixed on the cable. A removable element pos. 4 (Fig. 1, 2) with expanders pos. 5 (Fig. 1, 2,) is installed on the end part pos. 3 (Fig. 1, 2) using a threaded connection or a pin connection using a pin pos. 6 (Fig. 2). To prevent spontaneous disassembly of the cable during operation, the threaded connection of the monolithic end part pos. 3 (Fig. 1) is coated with an oil-resistant adhesive composition, and in the case of a pin connection, the pin pos. 6 (Fig. 2) is coated with an oil-resistant adhesive composition, and the protective sleeve pos. 7 (Fig.2) in the area of ​​the groove of the monolithic end part, it is fixed with a core in several places around the circumference.

[0036] Installation of a cable with a termination device in an oil producing or injection well is carried out as follows

[0037] The free end of the cable pos. 1 (Fig. 1, 2) in the protective cup of the termination device pos. 2 (Fig. 1, 2) with the disassembled end part pos. 3 (Fig. 1, 2,) is inserted into the sealing device (not indicated in Fig. 1, 2). Then, on the end part pos. 3 (Fig. 1, 2), a removable element pos. 4 (Fig. 1, 2) is fixed with expanders pos. 5 by a threaded (Fig. 1) or pin connection (Fig. 2) using a pin pos. 6 (Fig. 2). In this case, the threaded connection and the pin are covered with an adhesive composition resistant to petroleum products, and the protective sleeve, if present, is fixed on the end part along a special groove with a center punch. Next, a sealing device is installed and secured to the wellhead. After this, the cable is installed into the well to the calculated depth in accordance with the cable manufacturer's regulations and operating manual.

[0038] Thus, due to the presence of expanders with a calculated nominal bore diameter of 36, 38, 40, 42, 44 mm on the termination device, in the event of an emergency with a cable falling into the well, the possibility of the cable passing through the anti-flight ring (Rudak ring) with a nominal bore diameter of 34, 36, 38, 40, 42 mm and, as a consequence, damage to the bypass valve and the deep-well centrifugal pump is excluded, and the presence of a removable element in the termination device makes it possible to install the cable on the well with sealing devices of different types and bore sections without changing the design of the sealing device itself.

Claims

1. A termination device for a load-bearing heating cable, consisting of a protective cup made from a round pipe and a monolithic end portion, which is connected by a welded joint to the protective cup, in which the end of the cable is placed, consisting of interconnected conductive cores covered with a common electrical insulating coating, and the free cavity of the protective cup is filled with a dielectric heat-resistant sealing material, while the device itself is hermetically secured to the outer sheath of the cable, characterized in that the monolithic end portion is made disassemblable for the installation of removable elements with expanders.

2. The termination device according to paragraph 1, characterized in that the detachable end part is connected to the removable element by a threaded connection.

3. The termination device according to paragraph 1, characterized in that the detachable end part is connected to the removable element by a pin connection.

4. The termination device according to paragraph 1, characterized in that the diameter of the removable element is larger than the diameter of the protective cup and ranges from 36 mm to 48 mm.

5. The termination device according to paragraph 1, characterized in that the removable element of the detachable end part is made with expanders of cylindrical, rectangular or trapezoidal shape.

6. The termination device according to paragraph 1, characterized in that the expanders are installed on the removable element of the end part by means of a welded connection.

7. The termination device according to paragraph 1, characterized in that the expanders are manufactured as a single product with a removable element of the end part by milling from a monolithic cylindrical blank.

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