Flexible composite coiled tubing resistant to scratch and erosion

Abstract

The utility model relates to a continuous pipe, belongs to the technical field of oil and gas development, and particularly discloses a scratch-resistant and erosion-resistant flexible composite continuous pipe which comprises a central pipe, a transition layer, a reinforcing layer, a tensile layer and an outer protective layer which are sequentially arranged from inside to outside, and a wear-resistant and erosion-resistant epoxy resin inner coating is sprayed on the surface of an inner cavity of the central pipe. The outer protective layer is made of a scratch-resistant alloy steel material, so that the strength of the whole pipe is improved; the transition layer is made of nitrile rubber; the reinforcing layer and the tensile layer are formed by weaving composite material belts reinforced by special fiber belts, and a signal cable and a power cable are fixedly arranged in the reinforcing layer and the tensile layer respectively. The composite material continuous pipe can obviously improve the scratch resistance and the fluid erosion resistance of the inner wall, is beneficial to saving materials, improves the utilization rate of the existing composite material continuous pipe material, and is suitable for various oil and gas exploitation.

Description

TECHNICAL FIELD

[0001] The utility model relates to a continuous pipe, in particular to a flexible composite continuous pipe which is resistant to scratching and erosion. BACKGROUND

[0002] In the field of oil exploitation, oil extraction and liquid discharge is a key technology, and the pipe string used in this technology is mostly steel oil well pipe. The traditional steel oil well pipe needs to be connected single, and the operation amount is large, the cycle is long, the personnel operation intensity is big, and because of its large density, the cost of transportation and installation is high, therefore, the traditional steel oil well pipe has been difficult to meet the production requirements.

[0003] With the oil field exploitation entering the fine stage, the industry's requirement for energy saving and emission reduction, cost reduction and efficiency increase is increasingly urgent, and new requirements are put forward for continuous tubing operation equipment and pipe material. Non-metal flexible composite continuous pipe technology is a key technology for oil extraction and liquid discharge in the field of oil in recent years. The inner and outer layers of the composite continuous pipe are made of polymer materials, mainly including thermosetting and thermoplastic types. Compared with the steel oil well pipe, the non-metal flexible composite continuous pipe has good flexibility, can realize coiled supply, and has continuity in length, which is convenient for storage, installation and transportation. It has strong adaptability, high flexibility and light weight, and is suitable for various pipelines and environments, so it improves the construction efficiency and reduces the construction cost to a certain extent. However, during the operation process, it is found that the composite continuous pipe as the main conveying pipeline still has the following problems: the inner and outer layers are both high molecular materials, which leads to poor wear resistance and scratch resistance. During the pipe lifting and lowering operation, the inner and outer layers are easily scratched by sharp objects such as blowout preventers and slips, and the inner layer is easily eroded by fluid and difficult to repair. Special equipment is needed for cutting before use. In summary, the easy scratching and erosion of the pipe material has affected the popularization and application and production quality and efficiency of this type of pipe material. SUMMARY

[0004] In order to solve the above problems in the prior art, the utility model aims at providing a flexible composite continuous pipe which is resistant to scratching and erosion, so as to realize the purposes of scratch resistance and inner wall fluid erosion resistance.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme: a flexible composite continuous pipe which is resistant to scratching and erosion, comprising a center pipe, a transition layer, a reinforcing layer, a tensile layer and an outer protective layer arranged in sequence from inside to outside. The inner cavity surface of the center pipe is sprayed with an epoxy resin inner coating, and the outer protective layer is made of alloy steel material.

[0006] As a limitation of the utility model: the epoxy resin inner coating is a nano material reinforced epoxy resin inner coating, and the thickness of the epoxy resin inner coating is 500um-1000um.

[0007] As a limitation of the utility model: the outer protective layer is welded on the outside of the tensile layer by alloy steel material of CT80 strength grade, the yield strength of the alloy steel material is not less than 552MPa, the tensile strength is not less than 689MPa, the elongation is not less than 30%, and the wall thickness of the alloy steel material is not less than 2.5mm.

[0008] As a limitation of the utility model: the center pipe is extruded by high molecular material, and the high molecular material is one or several of modified polyethylene, polyvinylidene fluoride and polyketone.

[0009] As a limitation of the utility model: the transition layer is made of nitrile rubber, and the thickness is 3mm; the transition layer is tightly combined with the outer surface of the center pipe through vulcanization process.

[0010] As a limitation of the utility model: the reinforcing layer is composed of fiber belts wound on the outer layer of the transition layer, the winding angle of the fiber belts is 30°-45°, the winding layers of the fiber belts are even layers, a nitrile rubber sliding wear-resistant layer with a thickness of 1-2mm is coated between the fiber belts, and the reinforcing layer further comprises a nitrile rubber insulation layer with a thickness of 1-2mm coated on the outside of the fiber belts.

[0011] As a limitation of the utility model: the tensile layer is composed of fiber belts wound on the outer layer of the reinforcing layer, the winding angle of the fiber belts is 45°-60°, the winding layers of the fiber belts are even layers, and the tensile layer further comprises a nitrile rubber insulation layer with a thickness of 1-2mm coated on the outside of the fiber belts.

[0012] As a limitation of the utility model: the fiber belts are made of one or several of polyester fiber, nylon fiber, glass fiber, polyethylene fiber and aramid fiber and are mixed and woven in a bundle or a strip, the fiber belts are subjected to resin impregnation treatment and are wrapped by a resin matrix, and the resin is one of polyethylene resin, polypropylene resin and epoxy resin.

[0013] As a limitation of the utility model: a plurality of signal cables along the axial direction of the center pipe are embedded in the reinforcing layer, and a plurality of power cables along the axial direction of the center pipe are embedded in the tensile layer.

[0014] Compared with the prior art, the utility model has the beneficial effects that:

[0015] (1) The utility model sprays an epoxy resin inner coating layer on the surface of the inner cavity of the center pipe, can meet the requirements of corrosion resistance, wear resistance and washing resistance of the inner pipe wall in the construction process, uses alloy steel material as the protective layer of the outer layer, solves the problem of pipe scratch in use, effectively enhances the strength of the whole pipe material compared with the traditional continuous pipe using high molecular material as the outer protective layer, prolongs the service life of the continuous pipe, and saves the cost;

[0016] (2) The transition layer can effectively avoid the hard extrusion of the center pipe to the reinforcing layer and the tensile layer, and reduce the damage to the signal cable and the power cable; the reinforcing layer and the tensile layer have high tensile and extrusion resistance, can protect the signal cable and the power cable inside from being excessively stretched in the radial direction, and improve the tensile capacity and certain external impact resistance of the whole continuous pipe material;

[0017] (3) The utility model discloses a multi-layer composite material, relative to the traditional steel oil well pipe, has certain flexibility and bendability in a certain length range, can realize coiling supply, is convenient for storage and transportation, effectively reduces construction cost and promotes downhole operation efficiency.

[0018] In summary, the utility model discloses a multi-layer composite material structure, which is sprayed with an epoxy resin inner coating on the inner layer and uses alloy steel material on the outer layer. On the premise of not significantly increasing the cost, the utility model can significantly improve the scratch resistance and inner wall fluid erosion resistance, which is beneficial to saving materials and improving the utilization rate of existing composite continuous pipe materials, and is suitable for various oil and gas exploitation. BRIEF DESCRIPTION OF DRAWINGS

[0019] The utility model will be described further in detail in combination with the drawings and specific embodiments.

[0020] Figure 1 It is a cross section structure schematic diagram of the embodiment of the utility model.

[0021] In the figure: 1 - center pipe, 11 - epoxy resin inner coating, 2 - transition layer, 3 - reinforcing layer, 31 - signal cable, 4 - tensile layer, 41 - power cable, 5 - outer protective layer. DETAILED DESCRIPTION

[0022] The preferred embodiment of the utility model will be described in combination with the drawings. It should be understood that the flexible composite continuous pipe with scratch resistance and erosion resistance described herein is a preferred embodiment, which is only used to illustrate and explain the utility model, and does not constitute a limitation on the utility model.

[0023] The "in" and "out" and other orientation words or position relationships in the utility model are based on the orientation relationship in the drawings of the utility model specification, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element must have a specific orientation, a specific orientation structure and operation, so it cannot be understood as a limitation on the content protected by the utility model. EMBODIMENT

[0024] The embodiment is e Figure 1As shown, it is a flexible composite coiled tubing with anti-scratch and erosion, which comprises a center pipe 1, a transition layer 2, a reinforcing layer 3, a tensile layer 4 and an outer protective layer 5 arranged from inside to outside. A plurality of signal cables 31 along the axial direction of the center pipe are embedded in the reinforcing layer 3, and a plurality of power cables 41 along the axial direction of the center pipe are embedded in the tensile layer 4.

[0025] The center pipe 1 serves as a fluid circulation channel during the downhole operation of the coiled tubing, which is extruded from a high polymer material, specifically, the high polymer material is one or more of modified polyethylene, polyvinylidene fluoride and polyketone. An epoxy resin inner coating 11 is sprayed on the inner surface of the center pipe 1, in this embodiment, the epoxy resin inner coating 11 is a nano material reinforced epoxy resin inner coating, specifically, the epoxy resin inner coating 11 contains 5% to 10% of a reinforcing phase of nano WC or 8% to 12% of nano Al2O3, and the thickness of the epoxy resin inner coating 11 is 500um to 1000um, which can meet the requirements of corrosion resistance, wear resistance and erosion resistance during construction.

[0026] The transition layer 2 is arranged between the center pipe 1 and the reinforcing layer 3, and is tightly attached to the outer surface of the center pipe 1 through vulcanization process. The material of the transition layer 2 is nitrile rubber material which can be continuously used at 100℃, and the thickness of the transition layer 2 is 3mm. The transition layer 2 can play a role of buffering, wear resistance and anti-skid, and can effectively avoid direct hard extrusion between the center pipe 1 and the reinforcing layer 3.

[0027] The reinforcing layer 3 is composed of fiber belts wound on the outer layer of the transition layer 2. The fiber belts are woven in bundles or strips from one or more of polyester fiber, nylon fiber, glass fiber, polyethylene fiber and aramid fiber, and are treated by resin impregnation and wrapped by a resin matrix, which is one of polyethylene resin, polypropylene resin or epoxy resin. The width of the fiber belts is between 30mm and 40mm, and the fiber belts are tightly woven or wound on the outside of the transition layer at a certain pitch and winding angle. Specifically, the pitch is determined according to different product specifications, and the winding angle is generally selected to be 30° to 45°. The number of layers of the fiber belts is an even number, and the specific number of layers is determined according to the tensile set value. A nitrile rubber sliding wear-resistant layer (not shown in the figure) with a thickness of 1mm to 2mm is coated between the fiber belts. A plurality of signal cables 31 along the axial direction of the center pipe 1 are embedded in the reinforcing layer 3. The main role of the reinforcing layer 3 is to protect the internal signal cables 31 from excessive stretching by relying on its high tensile and anti-extrusion performance during the downhole operation of the composite pipe. In order to further improve the tensile capacity and external impact resistance of the reinforcing layer 3, the reinforcing layer 3 further comprises a nitrile rubber insulation layer (not shown in the figure) with a thickness of 1mm to 2mm coated on the outside of the reinforcing layer 3.

[0028] The material of the tensile layer 4 is the same as that of the reinforcing layer 3, and the tensile layer 4 is composed of fiber bands wound outside the reinforcing layer 3. The fiber bands are composed of one or more of polyester fiber, nylon fiber, glass fiber, polyethylene fiber and aramid fiber in a bundle or strip. The fiber bands are treated by resin impregnation and wrapped by a resin matrix. The resin is one of polyethylene resin, polypropylene resin or epoxy resin. The width of the fiber bands is between 30 and 40 mm, and the fiber bands are tightly woven or wound outside the reinforcing layer 3 at a certain pitch and winding angle. Specifically, the pitch is determined according to different product specifications, and the winding angle is generally selected to be 45° to 60°. The number of layers of the fiber bands is an even number, and the specific number of layers is determined according to the tensile set value design. A plurality of power cables 41 along the axis of the central pipe 1 are embedded in the tensile layer 4. In order to further improve the tensile capacity and external impact resistance of the tensile layer 4, the tensile layer 4 further includes a butyl rubber insulation layer (not shown in the figure) with a thickness of 1 to 2 mm wrapped outside the tensile layer 4.

[0029] The outer protective layer 5 is made of alloy steel material, which can effectively improve the overall strength and surface scratch resistance of the continuous pipe. Specifically, the outer protective layer 5 is made of alloy steel material with a CT80 strength grade welded outside the tensile layer 4. The yield strength of the alloy steel material is not less than 552 MPa, the tensile strength is not less than 689 MPa, and the elongation is not less than 30%. The wall thickness of the alloy steel material is not less than 2.5 mm.

[0030] The embodiment structure is completed from inside to outside, first, one or several of modified polyethylene, polyvinylidene fluoride and polyketone are extruded into a center pipe 1, a layer of epoxy resin protective layer with 5%-10% nanometer WC or 8%-12% nanometer Al2O3 strengthening phase and a thickness of 500um-1000um is uniformly sprayed in the inner cavity of the center pipe 1 by using thermal spraying technology; then, a layer of nitrile rubber transition layer 2 with a thickness of about 3mm is processed outside the center pipe 1 by using vulcanization technology; then, the polyester fiber, nylon fiber (or one or several of polyester fiber, nylon fiber, glass fiber, polyethylene fiber and aramid fiber) are mixed and woven into a reinforced composite fiber tape with a width of 30-40mm, the fiber tape is tightly wound outside the nitrile rubber transition layer 2 with a certain pitch and a winding angle of 45° (or any angle between 30°-45°), the number of winding layers is even, the number of weaving layers is determined according to the design of the tension setting value, the fiber tape is coated with polyethylene resin (or one of polypropylene resin and epoxy resin), the polyethylene resin is cured by heating treatment, a layer of nitrile rubber rubber material with a thickness of 1-2mm is coated between the reinforced fiber tapes as a sliding wear-resistant layer, then a 1-2mm nitrile rubber rubber material insulation separation layer is coated outside the reinforced layer 3; then, the fiber tape woven with glass fiber (or one or several of polyester fiber, nylon fiber, glass fiber, polyethylene fiber and aramid fiber) is impregnated with a tensile layer 4 composite material fiber tape with a certain pitch and a winding angle of 60° (or any angle between 45°-60°) tightly woven or wound outside the insulation separation layer of the reinforced layer 3, the width is 30-40mm, the number of winding layers is even, the number of weaving layers is determined according to the design of the tension setting value, the fiber tape is coated with epoxy resin, the epoxy resin is cured by heating treatment; finally, the outer protective layer 5 of alloy steel material is welded and coated outside the tensile layer 4 to make it an integral whole. Through the above steps, the assembly and production of the flexible composite continuous pipe material with anti-scratch and erosion are finally completed.

Claims

1. A flexible composite coiled tubing that is scratch and erosion resistant, characterized by: The invention comprises a central tube, a transition layer, a reinforcement layer, a tensile layer and an outer protective layer which are arranged in sequence from the inside to the outside. The inner cavity surface of the central tube is sprayed with an epoxy resin inner coating, and the outer protective layer is made of alloy steel material.

2. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The epoxy resin inner coating is a nano material reinforced epoxy resin inner coating, and the thickness of the epoxy resin inner coating is 500um to 1000um.

3. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The outer protective layer is welded on the outside of the tensile layer with an alloy steel material of CT80 strength grade. The yield strength of the alloy steel material is not less than 552MPa, the tensile strength is not less than 689MPa, the elongation is not less than 30%, and the wall thickness of the alloy steel material is not less than 2.5mm.

4. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The central tube is formed by extrusion of a polymer material, and the polymer material is one or more of modified polyethylene, polyvinylidene fluoride, and polyketone.

5. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The transition layer is made of nitrile rubber material with a thickness of 3 mm. The transition layer is tightly fitted to the outer surface of the central tube through a vulcanization process.

6. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The reinforcement layer is composed of a fiber belt wrapped around the outer layer of the transition layer. The winding angle of the fiber belt is 30° to 45°, the number of winding layers of the fiber belt is an even number, and a nitrile rubber sliding and wear-resistant layer with a thickness of 1 to 2 mm is wrapped between the fiber belts. The reinforcement layer also includes a nitrile rubber insulating layer with a thickness of 1 to 2 mm wrapped around the outside of the fiber belt.

7. The scratch- and erosion-resistant flexible composite coiled tubing according to claim 1, characterized in that: The tensile layer is composed of a fiber tape wrapped around the outer layer of the reinforcement layer. The winding angle of the fiber tape is 45° to 60°, and the number of winding layers of the fiber tape is an even number. The tensile layer also includes a nitrile rubber insulating layer with a thickness of 1 to 2 mm wrapped around the outside of the fiber tape.

8. The scratch- and erosion-resistant flexible composite coiled tubing according to any one of claims 6 and 7, characterized in that: The fiber belt is woven from one or more of polyester fiber, nylon fiber, glass fiber, polyethylene fiber, and aramid fiber in bundles or belts. The fiber belt is impregnated with resin and wrapped with a resin matrix. The resin is one of polyethylene resin, polypropylene resin, or epoxy resin.

9. The scratch- and erosion-resistant flexible composite coiled tubing according to any one of claims 1 to 7, characterized in that: A plurality of signal cables along the axial direction of the central tube are buried in the reinforcement layer, and a plurality of power cables along the axial direction of the central tube are buried in the tension layer.

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