Cable conversion device

Abstract

The present invention proposes a cable conversion device, which includes a sealed container; a plurality of single-core cables passing through one end of the container and entering the inner cavity of the container; an integrated heating cable group passing through the other end of the container and entering the inner cavity of the container, wherein each heating cable of the integrated heating cable group is respectively connected to the corresponding single-core cable in the inner cavity of the container; an inorganic mineral insulation material is filled in the inner cavity of the container. The cable conversion device enables the integrated heating cable group to extend to the front of the pump, thereby heating the liquid in front of the pump, reducing the viscosity of the heavy oil, and further increasing the pump hanging height of the rod pump, reducing the lifting power of the pump, reducing the number of maintenance times of the rod pump, and extending the service life of the rod pump.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole tools for oil and gas wells, and in particular to a cable conversion device. Background Art

[0002] Oil, a strategic resource, plays a crucial role in a nation's operations. Daily life, industry, and military operations all rely on vast quantities of oil. While heavy oil reserves are plentiful, they are difficult to extract.

[0003] Existing technologies often use thin oil blending or mineral insulated heating cables to reduce the viscosity of heavy oil. However, the development of thin oil blending has been limited by the dwindling availability of thin oil resources. Cable heating, on the other hand, offers highly efficient heating within the wellbore, reducing temperature losses in the mixed fluid and achieving excellent wellbore lifting and viscosity reduction. However, in many pumped wells, space constraints prevent the heating cables from extending beyond the pumps, resulting in low temperatures at the pump inlet and a series of heavy oil lifting issues.

[0004] Therefore, it is necessary to provide a cable conversion device so that the heavy oil before the pump can also be heated. Summary of the Invention

[0005] In response to some or all of the above-mentioned technical problems existing in the prior art, the present invention proposes a cable conversion device. The cable conversion device allows a single-core cable to pass through the pump first, and then converts it into an integrated heating cable group that extends in the oil pipe to electrically heat the liquid medium in front of the pump. As a result, the integrated heating cable group of the cable conversion device can heat the heavy oil in front of the pump, ensure the temperature of the liquid medium in front of the pump, reduce the viscosity of the heavy oil, and further increase the pump hanging height of the rod pump, reduce the lifting power of the pump, reduce the number of rod pump maintenance, and extend the service life of the rod pump. At the same time, the single-core cable can also be used to supplement the heating of the liquid medium after the rod pump to ensure the outlet temperature of the wellhead, which is beneficial to reduce back pressure and transport oil in the gathering pipeline.

[0006] According to the present invention, a cable conversion device is provided, comprising:

[0007] Closed container,

[0008] Multiple single-core cables pass through one end of the container and enter the inner cavity of the container.

[0009] The integrated heating cable group passes through the other end of the container and enters the inner cavity of the container. Each heating cable of the integrated heating cable group is connected to the corresponding single-core cable in the inner cavity of the container.

[0010] Inorganic mineral insulation filled in the inner cavity of the container.

[0011] In one embodiment, an axially extending connection blind hole is provided in the connection section of one of the single-core cable and the heating cable, the other connection section is inserted into the blind hole, and a fixing piece is used to radially pass through the single-core cable and the heating cable to achieve a fixed connection between the two.

[0012] In one embodiment, a fixing sleeve is sleeved on the outer wall of the single-core cable or the heating cable provided with a blind hole, and the fixing sleeve is provided with a fixing hole for a fixing member configured as a rivet to pass through.

[0013] In one embodiment, a plurality of grooves are engraved on the outer wall of the connecting section of the heating cable or the single-core cable that is not provided with a blind hole.

[0014] In one embodiment, the inorganic mineral insulation is magnesium oxide powder.

[0015] In one embodiment, the magnesium oxide powder includes three types of magnesium oxide powders with particle sizes of 200 mesh, 120 mesh and 100 mesh, which are evenly mixed. When the mass of the 200 mesh magnesium oxide powder is 1, the mass of the 120 mesh magnesium oxide powder is 0.5-2, and the mass of the 100 mesh magnesium oxide powder is 0.5-2.

[0016] In one embodiment, the container has:

[0017] cylindrical body,

[0018] The upper end cover is sealed at the upper end opening of the main body.

[0019] The lower end cover is sealed at the lower end opening of the main body.

[0020] The single-core cable extends downward through the upper end cover, while the integrated heating cable group extends upward through the lower end cover.

[0021] In one embodiment, the upper end of the lower end cap is cylindrical and at least partially inserted into the inner cavity of the main body, while the lower end is conical with a cross-sectional area gradually decreasing from top to bottom.

[0022] The upper end cover is / is constructed in a columnar shape and is partially inserted into the inner cavity of the main body. An anti-bending triangular cone cylinder for the single-core cable to pass through is provided on the upper end surface of the upper end cover.

[0023] In one embodiment, a ceramic sheet is disposed in the inner cavity of the container, and axial through holes are disposed on the ceramic sheet at intervals.

[0024] In one embodiment, it further comprises a bearing seat which is sleeve-fixedly arranged on the integrated heating cable assembly, and an axially extending connecting hole is arranged on the outer wall of the bearing seat.

[0025] Compared with the prior art, the advantage of the present invention is that the cable conversion device is connected to the single-core cable through an integrated heating cable group, so that the integrated heating cable group can extend to the front of the pump, thereby heating the liquid medium in front of the pump, reducing the viscosity of the heavy oil, and then increasing the pump hanging height of the rod pump, reducing the lifting power of the pump, reducing the number of maintenance times of the rod pump, and extending the service life of the rod pump. In addition, the cable conversion device passes the pump through the single-core cable, avoiding the problem of difficulty in passing the integrated heating cable group through the pump. In addition, the single-core cable can also be used to supplement the heating of the liquid medium after the pump of the rod pump to ensure the outlet temperature of the wellhead, which is beneficial to reducing back pressure and transporting oil in the gathering pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0027] Figure 1 shows a cross-sectional view of a cable conversion device according to one embodiment of the present invention;

[0028] Figure 2 A cross-sectional view of a connection between a single-core cable and a heating cable according to an embodiment of the present invention is shown.

[0029] In the drawings, like parts are given like reference numerals, but the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 1 shows a cable conversion device 100 according to the present invention. Figure 1 As shown, the cable conversion device 100 includes a sealed container 1, a plurality of single-core cables 2, an integrated heating cable group 3 and an inorganic mineral insulator (not shown in the figure). Among them, the plurality of single-core cables 2 all pass through one end of the container 1 and enter the inner cavity of the container 1. While the single-core cables 2 are used to transmit electrical energy to the integrated heating cable group 3, they also generate heat themselves to supplement the heating of the liquid medium after the pump of the rod pump, thereby ensuring the outlet liquid temperature of the wellhead. The integrated heating cable group 3 passes through the other end of the container 1 and enters the inner cavity of the container 1. At the same time, the integrated heating cable group 3 is composed of a plurality of heating cables 31, and each heating cable 31 is respectively connected to the single-core cable 2 in a one-to-one matching manner, thereby receiving electrical energy and generating heat to heat the liquid medium before the pump. The inorganic mineral insulator is filled in the inner cavity of the container 1 to play an insulating role and reduce the temperature of the connection point between the single-core cable 2 and the heating cable 31.

[0032] During use, the single-core cable 2 itself has a small diameter and can be easily distributed and arranged on the outside of the pump and the oil pipe behind the pump. After passing through the pump, the single-core cable 2 penetrates into the inner cavity of the oil pipe and is connected to the integrated heating cable group 3. Thus, the cable conversion device 100 enables the heating integrated heating cable group 3 to extend to the front of the pump to heat the liquid medium in front of the pump, reduce the viscosity of the heavy oil, and thereby increase the pump hanging height of the rod pump, reduce the lifting power of the pump, reduce the number of maintenance times of the rod pump, and extend the service life of the rod pump. Moreover, the cable conversion device 100 passes through the pump through the single-core cable 2, avoiding the problem of difficulty in passing the integrated heating cable group 3 through the pump. In addition, the single-core cable 2 can also be used to supplement the heating of the liquid medium behind the pump of the rod pump to ensure the outlet temperature of the wellhead, which is beneficial to reduce the back pressure and transport oil in the gathering pipeline.

[0033] In one embodiment, Figure 2 As shown, an axially extending connection blind hole 21 is provided in the connection section of the single-core cable 2. The corresponding connection section of the heating cable 31 is inserted into the blind hole 21. A fixing sleeve 4 is sleeved on the outer wall of the single-core cable 2. The fixing member 5 radially passes through the single-core cable 2, the heating cable 31 and the fixing sleeve 4 to connect the single-core cable 2 and the heating cable 31 together. The above connection method realizes a locked connection between the single-core cable 2 and the heating cable 31 in both the axial and radial directions, effectively avoiding the separation of the conductors of different materials due to different expansion coefficients under high temperature conditions, thereby ensuring the firmness of the connection.

[0034] Preferably, a plurality of grooves 32 are engraved on the outer wall of the connecting section of the heating cable 31. For example, the cross-section of the grooves 32 can be triangular, and the depth of the grooves 32 can be 0.5-1 mm. The provision of the grooves 32 can improve the conductivity between the single-core cable 2 and the heating cable 31, thereby ensuring heating efficiency.

[0035] During the production process, for example, a blind hole 21 with a diameter of 4 mm is provided in the connecting section of the single-core cable 2, and the axial dimension of the blind hole 21 is approximately 20 mm. Accordingly, five slots 32 are provided approximately 20 mm along the connecting section of the heating cable 31. Two slots 32 are provided on one circumferential side of the heating cable 31, and three slots 32 are provided on the other side, roughly opposite this side. Axially, the slots 32 on different sides are spaced apart from each other. The connecting section of the heating cable 31 is then inserted into the blind hole 21. A fixing sleeve 4 is then placed over the outer surface of the single-core cable 2. This fixing sleeve 4 has an inner diameter of 6 mm and is pre-defined with two sets of radially extending fixing holes 41. The centers of the fixing holes 41 are 5 mm and 15 mm from one end face of the fixing sleeve 4, respectively. Hydraulic pliers are then used to apply force to the two sets of fixing holes 41 to compress the fixing sleeve 4 and the single-core cable 2. Next, use a drill bit with a diameter of, for example, 2.6 mm, to drill holes at the corresponding locations of the fixing hole 41, penetrating the single-core cable 2 and the heating cable 31. Next, use an M2.4 stainless steel rivet to penetrate the fixing sleeve 4, the single-core cable 2, and the heating cable 31 to connect them. Finally, grind the rivet boss flat.

[0036] It should be noted that the above description uses the example of a blind hole 21 provided in a single-core cable 2 and the heating cable 3 inserted into the blind hole 21. However, the blind hole can also be provided in the heating cable 3, and this connection method is similar to the above, so it will not be described in detail here. It should be noted that in actual operation, the outer diameters of the two components to be connected are taken into consideration, and the blind hole is provided in the component with the larger outer diameter.

[0037] For example, the single-core cable 2 can be a copper conductor, and the heating cable 3 can be a nickel-chromium electric heating conductor. Of course, the present application is not limited to the above limitations. For example, the heating cable 3 can also be constructed as a copper alloy or other electric heating conductor.

[0038] In one embodiment, the inorganic mineral insulator is magnesium oxide powder. Preferably, the magnesium oxide powder includes three kinds of magnesium oxide powders with uniform particle sizes of 200 mesh, 120 mesh and 100 mesh, and when the mass of the 200 mesh magnesium oxide powder is 1, the 120 mesh magnesium oxide powder is 0.5-2, and the 100 mesh magnesium oxide powder is 0.5-2. And the magnesium oxide powder is calcined at high temperature and strongly extruded and arranged in the inner cavity of the container 1. Through the above-mentioned arrangement, not only the insulation of the connection between the heating cable 3 and the single-core cable 2 and the outside world is achieved, but also the thermal conductivity of the inorganic mineral insulator can be improved, the temperature of the connection point can be effectively dissipated, and it is helpful to achieve high electrothermal conversion performance.

[0039] In one embodiment, the container 1 comprises a cylindrical body 11, an upper end cap 12 sealingly disposed at the upper opening of the body 11, and a lower end cap 13 sealingly disposed at the lower opening of the body 11. The single-core cable 2 extends downward through the upper end cap 12, while the integrated heating cable assembly 3 extends upward through the lower end cap 13. This configuration of the container 1 provides a simple structure and facilitates the connection of the heating cable 3 and the single-core cable 2.

[0040] Preferably, the upper end of the lower end cap 13 is cylindrical and at least partially inserted into the inner cavity of the main body 11, while the lower end is tapered, with a gradually decreasing cross-sectional area from top to bottom. The main body 11 and lower end cap 13 are securely connected by welding, for example, with welds concentrated at the intersection of the main body 11 and lower end cap 13, ensuring a full weld. Simultaneously, the lower end of the lower end cap 13 is welded to the integrated heating cable assembly 3. Furthermore, the upper end cap 12 is cylindrical and partially inserted into the inner cavity of the main body 11. A kink-resistant triangular cone 14 is provided on the upper end surface of the upper end cap 12 for the passage of the single-core cables 2. The cross-sectional area of the cone 14 gradually increases from top to bottom. The main body 11 and upper end cap 12 are securely connected by welding, for example, with welds concentrated at the intersection of the main body 11 and upper end cap 12, ensuring a full weld. The number of cones 14 matches the number of single-core cables 2, and they are spaced apart on the upper end cap 12 to define the corresponding single-core cables 2. The upper and lower ends of the triangular cone 14 are welded to the single-core cable 2 and the upper end cap 12, respectively. The conical lower end cap 13 and the anti-bending triangular cone 14 effectively protect the integrated heating cable assembly 3 and the single-core cable 2. Furthermore, the main body 11, lower end cap 13, and upper end cap 12 are all made of stainless steel. Of course, the main body 11, lower end cap 13, and upper end cap 12 can also be made of 35CrMoA. This arrangement helps ensure the high mechanical strength and pressure-bearing sealing capability of the container 1.

[0041] In one embodiment, a disc-shaped ceramic sheet 6 is disposed within the inner cavity of the container 1. Axial through-holes 61 are also provided at intervals on the ceramic sheet 6. Preferably, the number of through-holes 61 matches the number of single-core cables 2, and the plurality of through-holes 61 are evenly distributed. The connecting sections of the heating cable 3 and the single-core cable 2 pass through the through-holes 61. The ceramic sheet 6 not only insulates the cables (heating cable 3 and single-core cable 2) from the outside world but also positions the cables and insulates them from each other.

[0042] In one embodiment, the cable conversion device 100 further includes a bearing seat 7 that is sleeved and fixedly mounted on the integrated heating cable assembly 3. During use, the bearing seat 7 rests on the stepped surface of the oil pipe, suspending the integrated heating cable assembly 3 extending downward within the oil pipe. Structurally, the bearing seat 7 has a cylindrical upper end and a cylindrical body with an enlarged diameter at the lower end. A connecting groove 72 is provided on the lower end surface of the larger-diameter cylinder. Furthermore, a connecting hole 71 extending axially through the outer wall of the larger-diameter cylinder is provided. For example, multiple connecting holes 71 may be spaced apart circumferentially. The connecting holes 71 communicate with the connecting grooves 72. During use, the lower end surface of the larger-diameter cylinder engages the stepped surface of the oil pipe, thereby suspending the integrated heating cable assembly 3 extending downward within the oil pipe. The interconnected connecting grooves 72 and connecting holes 71 provide for fluid communication within the oil pipe. The upper end of the bearing seat 7 is welded to the integrated heating cable assembly 3 for securement. It should be noted that the welding parts of the cable conversion device 100 need to be inspected and annealed after the overall welding is completed to eliminate welding stress, thereby ensuring the mechanical strength and high pressure-bearing sealing capability of the cable conversion device 100.

[0043] The cable conversion device 100 of the present application has a pressure-bearing and sealing capability of up to 35 MPa, can operate at high temperatures, for example, 250°, and can also ensure high electrothermal conversion performance.

[0044] In this application, the directional terms “upper” and “lower” are used with reference to the actual working position of the cable conversion device 100 .

[0045] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art may easily make changes or modifications within the technical scope disclosed in the present invention, and such changes or modifications shall be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A cable conversion device, characterized in that: include: Closed container, a plurality of single-core cables passing through one end of the container and entering into the inner cavity of the container; An integrated heating cable group passes through the other end of the container and enters the inner cavity of the container, wherein each heating cable of the integrated heating cable group is connected to the corresponding single-core cable in the inner cavity of the container. an inorganic mineral insulation filled in the inner cavity of the container; An axially extending connection blind hole is provided in the connection section of one of the single-core cable and the heating cable, the other connection section is inserted into the blind hole, and a fixing piece is used to radially pass through the single-core cable and the heating cable to achieve a fixed connection between the two; A fixing sleeve is sleeved on the outer wall of the single-core cable or the heating cable provided with the blind hole, and the fixing sleeve is provided with a fixing hole for the fixing member configured as a rivet to pass through; the fixing member radially passes through the single-core cable, the heating cable and the fixing sleeve to connect the single-core cable and the heating cable together, and realizes a locked connection between the single-core cable and the heating cable in both axial and radial directions; A plurality of grooves are carved on the outer wall of the connecting section of the heating cable or the single-core cable that is not provided with a blind hole; The plurality of grooves are arranged on different sides in the axial direction.

2. The cable conversion device according to claim 1, wherein: The inorganic mineral insulation is magnesium oxide powder.

3. The cable conversion device according to claim 2, wherein: The magnesium oxide powder includes three kinds of magnesium oxide powders with particle sizes of 200 mesh, 120 mesh and 100 mesh, which are evenly mixed. When the mass of the 200 mesh magnesium oxide powder is 1, the mass of the 120 mesh magnesium oxide powder is 0.5-2, and the mass of the 100 mesh magnesium oxide powder is 0.5-2.

4. The cable conversion device according to claim 3, characterized in that: The container has: cylindrical body, An upper end cover is sealed and arranged at the upper end opening of the main body. A lower end cover is sealed and arranged at the lower end opening of the main body. Wherein, the single-core cable extends downward through the upper end cover, and the integrated heating cable group extends upward through the lower end cover.

5. The cable conversion device according to claim 4, characterized in that: The upper end of the lower end cover is cylindrical and at least partially inserted into the inner cavity of the main body, while the lower end is conical with a cross-sectional area gradually decreasing from top to bottom. Or / and the upper end cover is constructed in a columnar shape and is partially inserted into the inner cavity of the main body, and an anti-bending triangular cone cylinder for the single-core cable to pass through is provided on the upper end surface of the upper end cover.

6. The cable conversion device according to any one of claims 1 to 5, characterized in that: A ceramic sheet is arranged in the inner cavity of the container, and axial through holes are arranged at intervals on the ceramic sheet.

7. The cable conversion device according to claim 6, wherein: It also includes a bearing seat that is sleeve-fixedly arranged on the integrated heating cable group, and an axially extending connecting hole is provided on the outer wall of the bearing seat.

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