Corrosion-resistant polyethylene-coated lining oil casing

Abstract

The utility model relates to a corrosion-resistant polyethylene-coated lining oil casing pipe, which comprises an outer pipe and an inner pipe, and has the technical key points that the outer pipe and the inner pipe are respectively polyethylene pipes, axial metal ribs are arranged in the pipe walls of the outer pipe and the inner pipe, an annular heat preservation cavity is formed between the outer pipe and the inner pipe, a plurality of radial supporting ribs are uniformly arranged in the annular heat preservation cavity, and the outer pipe and the inner pipe are made of polyethylene. Each radial supporting rib is composed of a middle vertical plate, an upper cylindrical supporting body arranged on the upper edge of the middle vertical plate and a lower cylindrical supporting body arranged on the lower edge of the middle vertical plate, an upper semicircular axial groove matched with the upper cylindrical supporting body is formed in the inner wall of the outer pipe, and a lower semicircular axial groove matched with the lower cylindrical supporting body is formed in the outer wall of the inner pipe. An outer wear-resisting layer is arranged on the outer wall of the outer pipe, an outer corrosion-resisting layer is arranged on the outer side of the outer wear-resisting layer, an inner wear-resisting layer is arranged on the inner wall of the inner pipe, and an inner corrosion-resisting layer is arranged on the outer side of the inner wear-resisting layer. The pressure resistance and the corrosion resistance are guaranteed, meanwhile, the heat preservation performance is good, and it is guaranteed that conveyed materials are not condensed.

Description

Technical Field

[0001] The utility model relates to the technical field of oil production pipelines, in particular to a corrosion-resistant polyethylene-coated inner-lined oil casing. Background Art

[0002] Oil and water wells typically use casing and tubing to withstand both well and production pressures, especially in deepwater production, where pressures are even higher. These tubing typically consists of a polyethylene inner tube and a stainless steel outer tube. The polyethylene inner tube provides corrosion resistance during oil transportation.

[0003] For example, CN 214467087 U discloses an ultra-high molecular weight polyethylene (UHMWPE)-coated oil pipe lined with an inner stainless steel pipe. The inner pipe has a first wear-resistant layer on its inner wall, a first anti-corrosion layer within the first wear-resistant layer, and a second wear-resistant layer, a thermal insulation layer, and a second anti-corrosion layer, positioned sequentially between the inner and outer walls of the stainless steel pipe. The outer wall of the stainless steel pipe is protected by an UHMWPE layer, which is then covered with silicone cloth, and the outer surface of the silicone cloth is coated with a fire-retardant coating. This design aims to improve the overall strength, corrosion resistance, wear resistance, and fire resistance of the oil pipe by combining the first wear-resistant layer, the first anti-corrosion layer, the second wear-resistant layer, the second anti-corrosion layer, the thermal insulation layer, the UHMWPE layer, the silicone cloth, and the fire-retardant coating. However, the following issues remain: While the metal outer pipe has strong pressure resistance, it has poor corrosion resistance. After years of use, the protective layer on the outer wall of the stainless steel pipe can develop leaks, significantly shortening its service life. Utility Model Content

[0004] The purpose of the utility model is to provide a corrosion-resistant polyethylene-coated oil casing with a reasonable structure and reliable use to solve the above problems, which not only ensures pressure resistance and corrosion resistance, but also has good thermal insulation performance to ensure that the conveyed material does not condense.

[0005] The technical solution of the utility model is:

[0006] A corrosion-resistant polyethylene coated lined oil casing, comprising an outer tube and an inner tube arranged in the outer tube. The technical key points are: the outer tube and the inner tube are respectively made of polyethylene pipes, and a plurality of axial metal ribs are evenly embedded in the tube walls of the outer tube and the inner tube, and the axial metal ribs are parallel to the axial center line of the outer tube, and an annular insulation cavity is formed between the outer tube and the inner tube, and a plurality of radial support ribs are evenly arranged in the annular insulation cavity, and the radial support ribs are composed of a middle vertical plate, an upper cylindrical support body arranged at the upper edge of the middle vertical plate, and a lower cylindrical support body arranged at the lower edge of the middle vertical plate; an upper semicircular axial groove cooperating with the upper cylindrical support body is provided on the inner wall of the outer tube, and a lower semicircular axial groove cooperating with the lower cylindrical support body is provided on the outer wall of the inner tube; an outer wear-resistant layer is provided on the outer wall of the outer tube, and an outer corrosion-resistant layer is provided on the outer wall of the outer tube; an inner wear-resistant layer is provided on the inner wall of the inner tube, and an inner corrosion-resistant layer is provided on the outer wall of the inner tube.

[0007] The above-mentioned corrosion-resistant polyethylene coated oil-lined casing has a vacuum hole in communication with the annular heat-insulating cavity on the outside of the outer tube, and a plug is provided at the vacuum hole.

[0008] The above-mentioned corrosion-resistant polyethylene coated lined oil casing has an annular heat-insulating cavity filled with inert gas or heat-insulating material, and a plurality of through holes are provided at intervals on the middle vertical plate of the radial support rib.

[0009] The above-mentioned corrosion-resistant polyethylene coated lined oil casing has continuous arc-shaped shallow grooves evenly arranged on the outer wall of the outer tube to increase the adhesion of the outer wear-resistant layer, and the outer surface of the outer wear-resistant layer has continuous arc-shaped shallow grooves evenly arranged to increase the adhesion of the outer corrosion-resistant layer.

[0010] The above-mentioned corrosion-resistant polyethylene coated lined oil casing has continuous arc-shaped shallow grooves evenly arranged on the inner wall of the inner tube to increase the adhesion of the inner wear-resistant layer, and the outer surface of the inner wear-resistant layer is evenly provided with continuous arc-shaped shallow grooves to increase the adhesion of the inner corrosion-resistant layer.

[0011] The beneficial effects of the utility model are:

[0012] 1. When in use, evacuate the annular insulation cavity through the vacuum hole, and then inject inert gas or insulation material to enhance the insulation performance. The insulation performance is good and ensures that the conveyed material does not condense.

[0013] 2. Both the outer tube and the inner tube are not metal tubes and have strong corrosion resistance. At the same time, the arrangement of axial metal ribs and radial support ribs significantly improves the compression resistance of the utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of Example 1 of the present utility model;

[0015] Figure 2 yes Figure 1 It is the AA section;

[0016] Figure 3 yes Figure 1 Enlarged view of middle part B;

[0017] Figure 4 It is a structural diagram of embodiment 2 of the present utility model.

[0018] In the figure: 1. Outer corrosion-resistant layer, 2. Blockage, 3. Outer tube, 4. Radial support ribs, 401. Upper cylindrical support body, 402. Middle vertical plate, 403. Lower cylindrical support body, 5. Axial metal ribs, 6. Inner tube, 7. Inner corrosion-resistant layer, 8. Annular insulation cavity, 9. Outer wear-resistant layer, 10. Inner wear-resistant layer, 11. Through hole, 12. Insulation material. DETAILED DESCRIPTION

[0019] The utility model is described in detail according to the accompanying drawings. Example

[0020] like Figures 1 to 3 As shown, the corrosion-resistant polyethylene coated lined oil casing includes an outer pipe 3 and an inner pipe 6 arranged in the outer pipe 3.

[0021] The outer tube 3 and the inner tube 6 are respectively made of polyethylene pipes, and a plurality of axial metal ribs 5 are evenly embedded in the tube walls of the outer tube 3 and the inner tube 6 , respectively. The axial metal ribs 5 are parallel to the axis of the outer tube 3 .

[0022] An annular heat-insulating cavity 8 is formed between the outer tube 3 and the inner tube 6, and a plurality of radial support ribs 4 are evenly arranged in the annular heat-insulating cavity 8. The radial support ribs 4 are composed of a middle vertical plate 402, an upper cylindrical support body 401 provided on the upper edge of the middle vertical plate 402, and a lower cylindrical support body 403 provided on the lower edge of the middle vertical plate 402. An upper semicircular axial groove cooperating with the upper cylindrical support body 401 is provided on the inner wall of the outer tube 3, and a lower semicircular axial groove cooperating with the lower cylindrical support body 403 is provided on the outer wall of the inner tube 6. In this embodiment, an inert gas is injected into the annular heat-insulating cavity 8, and a plurality of through holes 11 are provided at intervals on the middle vertical plate 402 of the radial support ribs 4. A vacuum hole communicating with the annular heat-insulating cavity 8 is provided on the outer side of the outer tube 3, and a plug 2 is provided at the vacuum hole.

[0023] The outer wall of the outer tube 3 is provided with an outer wear-resistant layer 9, on the outer side of which is an outer corrosion-resistant layer 1. The inner wall of the inner tube 6 is provided with an inner wear-resistant layer 10, on the outer side of which is an inner corrosion-resistant layer 7. To enhance adhesion and prevent shedding, the outer wall of the outer tube 3 is uniformly provided with continuous shallow arcuate grooves, and the outer surface of the outer wear-resistant layer 9 is uniformly provided with continuous shallow arcuate grooves. The inner wall of the inner tube 6 is uniformly provided with continuous shallow arcuate grooves, and the outer surface of the inner wear-resistant layer 10 is uniformly provided with continuous shallow arcuate grooves.

[0024] Working principle:

[0025] When in use, the annular heat-insulating cavity 8 is evacuated through the vacuum hole, and then inert gas is injected to enhance the heat-insulating performance.

[0026] The present invention enhances its compressive strength through the provision of radial support ribs 4. Furthermore, the axial metal ribs 5 built into the outer tube 3 and inner tube 6 also enhance their inherent strength. Although neither the outer tube 3 nor the inner tube 6 is metal, the provision of the axial metal ribs 5 and radial support ribs 4 significantly improves the present invention's compressive strength and corrosion resistance. Example

[0027] like Figure 4 As shown, the corrosion-resistant polyethylene coated inner lining oil casing, the annular heat-insulating cavity 8 is filled with heat-insulating material 12 to enhance the heat-insulating performance.

[0028] The above detailed description of the embodiments of the present invention is intended to be a preferred embodiment of the present invention and should not be construed as limiting the scope of implementation of the present invention. Any equivalent changes and improvements made within the scope of the present invention shall still fall within the scope of this patent.

Claims

1. A corrosion-resistant polyethylene-coated lined oil casing, comprising an outer tube and an inner tube disposed within the outer tube, characterized in that: The outer tube and the inner tube are respectively made of polyethylene tubes, and a plurality of axial metal ribs are evenly embedded in the tube walls of the outer tube and the inner tube, respectively. The axial metal ribs are parallel to the axis of the outer tube, and an annular insulation cavity is formed between the outer tube and the inner tube. A plurality of radial support ribs are evenly arranged in the annular insulation cavity, and the radial support ribs are composed of a middle vertical plate, an upper cylindrical support body arranged on the upper edge of the middle vertical plate, and a lower cylindrical support body arranged on the lower edge of the middle vertical plate. An upper semicircular axial groove cooperating with the upper cylindrical support body is provided on the inner wall of the outer tube, and a lower semicircular axial groove cooperating with the lower cylindrical support body is provided on the outer wall of the inner tube. An outer wear-resistant layer is provided on the outer wall of the outer tube, and an outer corrosion-resistant layer is provided on the outer side of the outer wear-resistant layer. An inner wear-resistant layer is provided on the inner wall of the inner tube, and an inner corrosion-resistant layer is provided on the outer wall of the inner tube.

2. The corrosion-resistant polyethylene coated lined oil casing according to claim 1, characterized in that: A vacuum hole communicating with the annular heat-insulating cavity is provided on the outside of the outer tube, and a blockage is provided at the vacuum hole.

3. The corrosion-resistant polyethylene coated lined oil casing according to claim 1, characterized in that: The annular heat-insulating cavity is filled with inert gas or heat-insulating material, and a plurality of through holes are provided at intervals on the middle vertical plate of the radial support rib.

4. The corrosion-resistant polyethylene coated lined oil casing according to claim 1, characterized in that: The outer wall of the outer tube is evenly provided with continuous arc-shaped shallow grooves, and the outer surface of the outer wear-resistant layer is evenly provided with continuous arc-shaped shallow grooves.

5. The corrosion-resistant polyethylene coated lined oil casing according to claim 1, characterized in that: The inner wall of the inner tube is evenly provided with continuous arc-shaped shallow grooves, and the outer surface of the inner wear-resistant layer is evenly provided with continuous arc-shaped shallow grooves.

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