A submersible cable and its manufacturing method

Abstract

This invention provides a submersible cable, belonging to the field of cables. The submersible cable includes a conductive core, a heating core, a first wrapping layer, a heating layer, and a protective layer. The heating layer is electrically connected to the heating core. The protective layer is made of fibrous tape and fiberglass tape, which are cured together, giving the submersible cable advantages such as high tensile strength, light weight, and good flexibility. It can also heat the well at any time, saving manpower, material resources, and time costs, while avoiding environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of submersible cable technology, specifically to a submersible cable and its manufacturing method. Background Technology

[0002] Submersible cables are laid in oil wells, where working conditions are harsh, often involving high temperatures, high pressures, and highly corrosive environments containing oil and gas. Therefore, the performance requirements for the cables and the standards for each manufacturing process are extremely high.

[0003] Currently, submersible cables are difficult to lay due to their generally long length and excessive rigidity. Furthermore, their low tensile strength, heavy weight, and low flexibility make them prone to breakage and damage, necessitating frequent replacements and increasing costs. In addition, existing submersible cables typically use high-temperature steam for dewaxing, resulting in significant manpower, material resources, and time costs (low dewaxing efficiency) and severe environmental pollution. Summary of the Invention

[0004] The purpose of this invention is to address the problems of low tensile strength, heavy weight, and low flexibility of existing submersible cables, as well as the high manpower, material and time costs and serious environmental pollution caused by using high-temperature steam to dewax submersible cables. This invention provides a submersible cable and its manufacturing method to improve cable compressive strength, reduce cable weight, improve flexibility, improve dewaxing efficiency, save costs, and avoid environmental pollution.

[0005] In a first aspect, the present invention provides a submersible cable, the submersible cable comprising a conductive core, a heating core, a first wrapping layer, a heating layer and a protective layer, wherein the heating layer is electrically connected to the heating core; the protective layer is made of fibrous tape and glass fiber tape, and the fibrous tape and glass fiber tape are cured together.

[0006] Furthermore, the cable also includes a Kevlar fiber braided layer and a sheath, the sheath being made of PVC tape and fiberglass tape, which are cured together as a single unit.

[0007] Furthermore, the conductive core includes a first conductor, a first insulating layer, and a first covering layer;

[0008] The first insulating layer includes a first inner insulating layer and a first outer insulating layer, wherein the first inner insulating layer covers the first conductor and the first outer insulating layer covers the first inner insulating layer;

[0009] The first covering layer covers the first outer insulating layer.

[0010] Furthermore, the heating wire core includes a second conductor, a second insulation layer, and a second covering layer;

[0011] The second insulating layer includes a second inner insulating layer and a second outer insulating layer, wherein the second inner insulating layer covers the second conductor and the second outer insulating layer covers the second inner insulating layer;

[0012] The second covering layer covers the second outer insulating layer.

[0013] Furthermore, the cable also includes an insulating filler layer between the conductive core and the heating core and the first wrapping layer.

[0014] Furthermore, the heating layer is made of copper wire braid.

[0015] On the other hand, the present invention provides a method for manufacturing a submersible cable, characterized by comprising the following steps:

[0016] S1. The conductive core and the heating core are twisted together in a regular manner, and the first wrapping layer is wrapped around the conductive core and the heating core;

[0017] S2. A high-speed braiding machine is used to braid the heating layer on the first wrapping layer, and the heating layer is electrically connected to the heating wire core;

[0018] S3. Use a wrapping machine to wrap a protective layer around the heating layer.

[0019] Furthermore, the method also includes:

[0020] S4. A Kevlar fiber braided layer is woven around the protective layer using a high-speed braiding machine;

[0021] S5. Use a wrapping machine to wrap a protective sleeve around the Kevlar fiber braided layer.

[0022] Furthermore, before step S1, the following is included:

[0023] Solid copper rods are used to make both the heating and conductive conductors;

[0024] A first insulating layer is coated on a conductive conductor, and a first covering layer is wrapped on the first insulating layer;

[0025] A second insulating layer is coated on the heating conductor, and a second covering layer is wrapped on the second insulating layer.

[0026] Furthermore, step S1 also includes providing a filler layer between the conductive core and the heating core and the first wrapping layer.

[0027] This invention uses fiberless tape and glass fiber tape as protective layers, giving the submersible cable advantages such as high tensile strength, light weight, and good flexibility. This makes the submersible cable less prone to damage and extends its service life. By setting a heating layer and electrically connecting the heating layer to the heating wire core, heating can be applied to the well whenever dewaxing is needed, saving manpower, material resources, and time costs, while avoiding environmental pollution. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a partial cross-section of a submersible cable according to an embodiment of the present invention is shown.

[0030] Figure 2 A schematic diagram of a partial cross-section of a submersible cable according to another embodiment of the present invention is shown.

[0031] Figure 3 A schematic diagram of the cross-section of a conductive wire core according to an embodiment of the present invention is shown.

[0032] Figure 4 A schematic diagram of the cross-section of a heating wire core according to an embodiment of the present invention is shown.

[0033] Figure 5 A flowchart illustrating a method for manufacturing a submersible cable according to an embodiment of the present invention is shown.

[0034] Wherein: 1-Conductive core; 2-Heating core; 3-Filling layer; 4-First wrapping layer; 5-Heating layer; 6-Protective layer; 7-First conductor; 8-First insulation layer; 9-First covering layer; 10-Second conductor; 11-Second insulation layer; 12-Second covering layer; 13-Kevlar fiber braided layer; 14-Sheath. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0037] like Figure 1 As shown, this embodiment provides a submersible cable, including a conductive core 1, a heating core 2, a first wrapping layer 4, a heating layer 5, and a protective layer 6. The heating layer 5 is electrically connected to the heating core 2; the protective layer 6 is made of fibrous tape and fiberglass tape, and the fibrous tape and fiberglass tape are impregnated and cured into one piece.

[0038] Specifically, the first wrapping layer 4 can be made of glass ribbon. The first wrapping layer 4 wraps the conductive wire core 1 and the heating wire core 2. The heating layer 5 is wrapped on the first wrapping layer 4, and the protective layer 6 is wrapped on the heating layer 5.

[0039] The conductive core 1 is used for power transmission, and the heating core 2 is connected to the heating layer 5. The heat-conducting core is used to transmit current to the heating layer 5. The heating layer generates heat through the flow of the transmitted current, which plays a heating role. This allows the present application to heat the well at any time while transmitting power normally, which helps to save the cost of oil well dewaxing and avoid environmental pollution.

[0040] The protective layer 6 uses fiberless tape and fiberglass tape. The fiberless tape is made of alkali-free fiberglass yarn impregnated with high-temperature heat-curing polyester resin. After the fiberless tape is wrapped around the heating layer 5, the fiberglass tape is wrapped around the fiberless tape. After baking, the fiberless tape and fiberglass tape are impregnated and cured into one piece to form a protective layer. This gives the submersible cable advantages such as high tensile and impact strength, light weight, good flexibility, low elongation, no magnetic hysteresis and no eddy current. As a result, the submersible cable is not easily damaged and has a longer service life.

[0041] In practice, users can set the number of conductive cores 1 and heating cores 2 according to their actual needs. In addition, they can also set the length of the heating layer according to their actual needs to achieve the function of fixed-depth heating.

[0042] like Figure 1 As shown, there are three conductive cores 1 and one heating core 2. The heating layer is also shown. In actual use, the number of conductive cores 1 can be set according to the number and phase of the submersible pump in the oil well (e.g., three-phase power). The length of the heating layer, the length of the heating core, and the number of heating cores 2 can be set according to the depth of the oil well where the submersible pump is located.

[0043] For example, a submersible cable needs to supply power to two three-phase submersible pumps installed at a depth of 50 meters. In actual operation, the cable between 30 and 50 meters needs to be heated to remove wax. For this purpose, six conductive cores 1 are required to transmit power to the two submersible pumps. A heating core 2 with a length of 30 meters and a heating layer 5 with a length of 20 meters are also required. The end of the heating layer 5 is connected to the heating core 2, so that the current of the external heating control system is transmitted to the heating layer 5 through the heating core to control the heating of the heating layer 5, thereby achieving constant depth heating.

[0044] In this embodiment, with Figure 1 As shown in the example, conductive core 1 is used to transmit power to the downhole submersible pump. Heating core 2 is used to transmit the current obtained from the external heating control system to the heating layer 5, so that the current generates heat when flowing through the heating layer, thereby starting the heating function.

[0045] This submersible cable provides power to the submersible electric pump (SAP) in the oil well and performs dewaxing as needed. Before use, the external power supply system is electrically connected to the SSP in the well via the conductive core 1, and the external heating control system is electrically connected to the heating layer 5 inside the submersible cable via the heating core 2. During use, on the one hand, the power provided by the external power supply system is transmitted to the SSP downhole via the conductive core 1, enabling the SSP to operate; on the other hand, when dewaxing is required, the current provided by the external heating control system is transmitted to the heating layer 5 via the heating core 2, allowing the heating layer 5 to generate heat and thus achieve dewaxing.

[0046] Specifically, users can use the external heating control system described above to control the current supplied to the heating core 2 according to actual needs, thereby controlling the heating current in the heating layer 5 and thus regulating the heat generated by the heating layer 5.

[0047] As an illustrative embodiment of the present invention, the heating layer 5 is a copper mesh woven from oxygen-free copper wire with a diameter of 0.3mm-0.32mm. When the external heating control system supplies current (controllable) to the heating core 2, the current flows through the copper mesh. Since the copper mesh itself has a certain resistance, a certain amount of heat is generated when the current flows through the copper mesh, thereby heating the environment in which the cable is located, thus helping to achieve dewaxing in oil wells.

[0048] In addition, the use of copper mesh in the heating layer 5 helps to dissipate heat from the entire cable, and the electrical connection between the external heating control system and the heating layer 5 is achieved through the heating wire core 2. This helps the present invention to achieve temperature controllable and more effective dewaxing when oil well dewaxing is required, which helps to save the cost of oil well dewaxing and also helps to avoid environmental pollution.

[0049] The protective layer 6 can be made of Class B nonwoven tape and glass ribbon, and the Class B nonwoven tape and glass ribbon are cured together, with the Class B nonwoven tape as the inner layer and the glass ribbon as the outer layer.

[0050] like Figure 2 As shown, the present invention also provides another exemplary embodiment of a submersible cable, which further includes a Kevlar fiber braided layer 13 and a sheath 14. The Kevlar fiber has low density, no creep, and a tensile strength generally above 3500 MPa, which is 7-9 times the tensile strength of steel. It also has the characteristics of corrosion resistance and high modulus, and the processability of textile fibers. This makes the cable have the characteristics of high tensile strength, corrosion resistance, high modulus, and good flexibility.

[0051] The Kevlar fiber braided layer 13 is disposed between the protective layer 6 and the sheath 14. The sheath is made of the same material and has the same structure as the protective layer, which further improves the strength, impact resistance, and other specific properties of the submersible cable of the present invention.

[0052] like Figure 3 As shown, the conductive core 1 includes a first conductor 7, a first insulating layer 8, and a first covering layer 9. The first insulating layer 8 adopts a double-layer structure. Specifically, the first insulating layer 8 includes a first inner insulating layer and a first outer insulating layer. The first inner insulating layer covers the first conductor 7, the first outer insulating layer covers the first inner insulating layer, and the first covering layer 9 covers the first outer insulating layer.

[0053] like Figure 4 As shown, the heating wire core 2 includes a second conductor 10, a second insulation layer 11, and a second covering layer 12. The second insulation layer 11 adopts a double-layer structure. Specifically, the second insulation layer 11 includes a second inner insulation layer and a second outer insulation layer. The second inner insulation layer covers the second conductor 10, the second outer insulation layer covers the second inner insulation layer, and the second covering layer 12 covers the second outer insulation layer.

[0054] The first conductor 7 and the second conductor 10 are made of solid copper rods through continuous extrusion and annealing using an extrusion press. The first conductor is of the first type in GB / T3956-2008 Conductors of Cables. The approximate dimensions of the first type of conductor are shown in Table 1 below.

[0055] Table 1

[0056]

[0057] The first and second inner insulation layers are made of polyimide F46 composite film, for example, both are made of 7.25KV grade polyimide F46 composite film.

[0058] The first and second outer insulation layers are made of fluoroplastics, which provides gas and water resistance.

[0059] Both the first covering layer 9 and the second covering layer 12 are made of glass ribbon, which helps to isolate the external environment from the heating conductor and the conductive conductor.

[0060] As an illustrative embodiment of the present invention, the submersible cable further includes a filler layer 3 filled between the first wrapping layer 4 and the conductive core 1 and the heating core 2, wherein the filler layer 3 is made of glass fiber.

[0061] In practice, the stranded conductive core 1 and heating core 2 can be wrapped together by the first wrapping layer 4, and glass fiber (corresponding to the filling layer 3) can be filled between the first wrapping layer 4 and the conductive core 1 and the heating core 2, so that the shape is round, the structure is stable and the influence of external temperature on the conductive core 1 and the heating core 2 is effectively isolated.

[0062] like Figure 5 As shown, as another exemplary embodiment of the present invention, the present invention provides a method for manufacturing a submersible cable, comprising the following steps:

[0063] S1. The conductive core and the heating core are twisted together in a regular manner, and the first wrapping layer is wrapped around the conductive core and the heating core;

[0064] S2. A high-speed braiding machine is used to braid the heating layer on the first wrapping layer, and the heating layer is electrically connected to the heating wire core;

[0065] S3. Use a wrapping machine to wrap a layer of non-woven tape on the heating layer, then wrap a layer of glass ribbon around the non-woven tape layer, and impregnate and cure the wrapped non-woven tape layer and glass ribbon layer into one to form a protective layer;

[0066] S4. A Kevlar fiber braided layer is woven around the outer edge of the protective layer using a high-speed braiding machine;

[0067] S5. A wrapping machine is used to wrap a non-woven tape layer around a Kevlar fiber braided layer, and then a glass ribbon layer is wrapped around the non-woven tape layer. The non-woven tape layer and the glass ribbon layer wrapped around the Kevlar fiber braided layer are impregnated and cured into a whole to form a sheath.

[0068] To provide a more specific and detailed understanding of the present invention, another exemplary embodiment of a method for manufacturing a submersible cable is provided.

[0069] Before step S1, the following are included:

[0070] Solid copper rods are used to make both the heating and conductive conductors;

[0071] A first insulating layer is coated on a conductive conductor, and a first covering layer is wrapped on the first insulating layer. The first insulating layer includes a first inner insulating layer and a first outer insulating layer.

[0072] A first insulating layer and a second insulating layer are coated on the heating conductor, and a second covering layer is wrapped on the second insulating layer. The second insulating layer includes a first inner insulating layer and a second inner insulating layer.

[0073] The first inner insulation layer and the second inner insulation layer are both made of polyimide film, the first outer insulation layer and the second outer insulation layer are both made of fluoroplastic, and the first covering layer and the second covering layer are made of glass ribbon.

[0074] In practice, solid copper rods are continuously extruded and annealed using an extruder to produce conductive and heating conductors; polyimide films are wrapped in four layers onto the conductive and heating conductors using a film wrapping machine, with an overlap rate of 50%; and the polyimide films are firmly bonded to the conductive and heating conductors by high-temperature sintering at ≥320℃.

[0075] Fluoroplastics are extruded on polyimide films that are conductive conductors and polyimide films that are heated conductors using a high-temperature extruder. The screw of the high-temperature extruder needs to be a specially made screw with a compression ratio of 1:1.25 to 1:1.35.

[0076] A layer of glass ribbon is wrapped around a conductive conductor and a heating conductor that have been extruded with fluoroplastics, with each layer of glass ribbon having an overlap rate of 50%.

[0077] Preferably, in step S1 above, the conductive wire core and the heating wire core are twisted together, and the twisting pitch ratio is in the range of 28 to 30 times.

[0078] Preferably, step S2 above uses a high-speed braiding machine to braid the heating layer on the first wrapping layer. Specifically, the high-speed braiding machine is used to form a uniform copper mesh braided layer with a density ≥75% on the first wrapping layer using oxygen-free copper wire with a diameter of 0.3mm-0.32mm. This copper mesh braided layer is the heating layer. The ends of the copper mesh in the heating layer are electrically connected to the heating wire core.

[0079] Preferably, step S3 above involves using a wrapping machine to wrap a layer of non-woven adhesive tape and a layer of glass fiber tape around the heated layer, and then impregnating and curing the non-woven adhesive tape and the glass fiber tape layer together to form a protective layer. Specifically, this includes:

[0080] A layer of nonwoven tape is wrapped around the heating layer using a wrapping machine, and then a layer of glass ribbon is wrapped around the nonwoven tape. After wrapping, the nonwoven tape is left to stand in a 130℃ oven for 12 hours to bake and cure, so that the nonwoven tape and glass ribbon are impregnated and cured into one, forming a protective layer. The overlap rate of each layer of nonwoven tape and glass ribbon is 50%.

[0081] Preferably, the Kevlar fiber braided layer is made of high-strength Kevlar carbon fiber, woven onto the protective layer by a high-speed braiding machine. The weaving requires uniform Kevlar carbon fiber coverage, a density of ≥80%, and a strength of ≥3500 MPa.

[0082] As a preferred embodiment, the method of implementing S5 includes: wrapping a layer of non-woven tape around a Kevlar fiber braided layer using a wrapping machine, then wrapping a layer of glass ribbon around the non-woven tape, and then baking and curing it in an oven at 130°C for 12 hours. The non-woven tape and glass ribbon are impregnated and cured into one piece to form a sheath, wherein the overlap rate of each layer of non-woven tape and glass ribbon is 50%.

[0083] For the same or similar parts among the various embodiments in this specification, please refer to each other.

[0084] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A submersible cable, characterized in that, The submersible cable includes a conductive core, a heating core, a first wrapping layer, a heating layer, and a protective layer. The heating layer is electrically connected to the heating core. The protective layer is made of non-woven tape and fiberglass tape, and the non-woven tape and fiberglass tape are cured into one piece. The conductive core is used for power transmission, and the heating core is used to transmit current to the heating layer; the heating layer generates heat through the flow of the transmitted current, thus playing a heating role. The cable also includes a Kevlar fiber braided layer and a sheath, the sheath being made of non-woven tape and fiberglass tape, and the non-woven tape and fiberglass tape being cured into one piece; The non-woven tape is made of alkali-free glass fiber yarn impregnated with high-temperature heat-curing polyester resin. After the non-woven tape is wrapped around the heating layer, the glass fiber tape is wrapped around the non-woven tape. After baking, the non-woven tape and the glass fiber tape are impregnated and cured into a whole to form a protective layer. The conductive and heating wire cores are regularly twisted together, and a first wrapping layer is used to wrap both the conductive and heating wire cores. A high-speed braiding machine is used to braid a heating layer on the first wrapping layer, and the heating layer is electrically connected to the heating wire core. A non-woven tape layer is wrapped on the heating layer using a wrapping machine, and then a fiberglass ribbon layer is wrapped around the non-woven tape layer. The wrapped non-woven tape layer and fiberglass ribbon layer are impregnated and cured to form a protective layer. A Kevlar fiber braided layer is used to braid the outer layer of the protective layer using a high-speed braiding machine. A non-woven tape layer is wrapped on the Kevlar fiber braided layer using a wrapping machine, and then a fiberglass ribbon layer is wrapped around the non-woven tape layer. The wrapped non-woven tape layer and fiberglass ribbon layer are impregnated and cured to form a sheath.

2. The submersible cable according to claim 1, characterized in that, The conductive core includes a first conductor, a first insulating layer, and a first covering layer; The first insulating layer includes a first inner insulating layer and a first outer insulating layer, wherein the first inner insulating layer covers the first conductor and the first outer insulating layer covers the first inner insulating layer; The first covering layer covers the first outer insulating layer.

3. The submersible cable according to claim 1, characterized in that, The heating wire core includes a second conductor, a second insulation layer, and a second covering layer; The second insulating layer includes a second inner insulating layer and a second outer insulating layer, wherein the second inner insulating layer covers the second conductor and the second outer insulating layer covers the second inner insulating layer; The second covering layer covers the second outer insulating layer.

4. The submersible cable according to claim 1, characterized in that, The cable also includes an insulating filler layer between the conductive core and the heating core and the first wrapping layer.

5. The submersible cable according to claim 1, characterized in that, The heating layer is made of copper wire braid.

6. The method for manufacturing a submersible cable according to claim 1, characterized in that, Includes the following steps: S1. The conductive core and the heating core are twisted together in a regular manner, and the first wrapping layer is wrapped around the conductive core and the heating core; S2. A high-speed braiding machine is used to braid the heating layer on the first wrapping layer, and the heating layer is electrically connected to the heating wire core; S3. Use a wrapping machine to wrap a non-woven tape layer on the heating layer, then wrap a glass ribbon layer on the outside of the non-woven tape layer, and impregnate and cure the wrapped non-woven tape layer and glass ribbon layer into one to form a protective layer; S4. A Kevlar fiber braided layer is woven around the outer edge of the protective layer using a high-speed braiding machine; S5. Using a wrapping machine, wrap a non-woven tape layer around the Kevlar fiber braided layer, then wrap a glass ribbon layer around the non-woven tape layer, and impregnate and cure the non-woven tape layer and glass ribbon layer wrapped on the Kevlar fiber braided layer into a whole to form a sheath.

7. The method for manufacturing a submersible cable according to claim 6, characterized in that, Before step S1, the following are included: The first and second conductors are made of solid copper rods. A first insulating layer is coated on a first conductor, and a first covering layer is wrapped on the first insulating layer to obtain a conductive wire core; A second insulating layer is coated onto the second conductor, and a second covering layer is wrapped around the second insulating layer to obtain a heating wire core.

8. The method for manufacturing a submersible cable according to claim 7, characterized in that, Step S1 also includes providing an insulating filler layer between the conductive core and the heating core and the first wrapping layer.

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