A method of preparing a defect in an outermost tensile armour layer of a flexible riser

Abstract

The application provides a flexible riser outermost tensile armor layer defect preparation method, and belongs to the field of flexible riser defect preparation, and comprises the following steps: step 1, a flexible riser of a preset length is cut off as an experimental steel pipe base body; step 2, both ends of the flexible riser are fixed; step 3, the outer protective layer of the flexible riser is cut; step 4, a defect is processed on the outermost tensile armor layer; and step 5, the outer protective layer of the flexible riser is restored. The method solves the problem that the outermost tensile armor layer of the flexible riser is difficult to be predefected at present, and the flexible riser outermost tensile armor layer defect prepared by the application can effectively simulate corrosion and fracture defects of the armor layer.

Description

Technical Field

[0001] This invention relates to the field of flexible riser defect preparation, and in particular to a method for preparing defects in the outermost tensile armor layer of a flexible riser. Background Technology

[0002] During the operation and maintenance of offshore flexible risers, oil and gas media can permeate into the annulus, creating a corrosive environment that corrodes the tensile armor layer. Furthermore, the movement of the flexible riser causes friction and fatigue stress between the layers of the tensile armor layer, leading to corrosion thinning and fatigue fracture of the outermost tensile armor layer. These problems compromise the integrity of the flexible riser, reducing its mechanical properties and potentially causing damage or breakage, resulting in major production accidents, severe environmental damage, and endangering personal and property safety. Therefore, to prevent accidents, it is necessary to use non-destructive testing (NDT) methods to identify defects within the metal armor layer for timely repair. However, to verify the effectiveness of NDT methods, it is necessary to prepare flexible risers with defects such as corrosion and fracture in the armor layer. Currently, there is a lack of effective defect preparation methods for offshore flexible risers. Summary of the Invention

[0003] In view of this, the present invention aims to propose a method for preparing defects in the outermost tensile armor layer of flexible risers. This method enables the preparation of defects in the outermost tensile armor layer within existing flexible riser sections, thereby solving the current problem of the lack of prefabricated defects in the outermost tensile armor layer of flexible risers.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: a method for preparing defects in the outermost tensile armor layer of a flexible riser, comprising the following steps:

[0005] Step 1: Cut a flexible riser of a predetermined length as the experimental steel pipe base;

[0006] Step 2: Secure both ends of the flexible riser;

[0007] Step 3: Cut the outer protective layer of the flexible riser;

[0008] Step 4: Process defects on the outermost tensile armor layer;

[0009] Step 5: Restore the outer protective layer of the flexible riser.

[0010] Furthermore, step 2 specifically involves using a flexible riser clamping device or welding method to fix or weld the metal layers on the two ends of the flexible riser together.

[0011] Furthermore, step 3 includes: first, cutting along the outer protective layer of the flexible riser, but not exceeding the thickness of the outer protective layer, cutting into a closed shape; then, removing the cut outer protective layer to expose the outermost tensile armor layer; if the outer protective layer in the cut area cannot be removed, softening the outer protective layer by local heating and then removing it.

[0012] Furthermore, in step 4, when processing defects on the outermost tensile armor layer, select one or more flat steels of the outermost tensile armor layer to process defects, including hole defects, slot defects and fracture defects;

[0013] The hole defects are selected with different diameters and arranged at the same spacing; the groove defects are selected with different lengths, widths and depths and arranged at the same spacing; the fracture defects are selected at the fracture locations of different outermost tensile armor layer flat steels.

[0014] Furthermore, step 5 includes: first, putting the outer protective layer removed in step 3 back in place; then, heating the outer protective layer at the notch to fuse the removed outer protective layer with the outer protective layer of the flexible riser; and finally, polishing the connection point of the outer protective layer to make it smooth.

[0015] Furthermore, step 5 includes: first, putting the outer protective layer removed in step 3 back in place; then, heating a glue stick made of the same material as the outer protective layer to melt the heated end of the glue stick and dripping glue into the notch to fuse the removed outer protective layer and the outer protective layer of the flexible riser together; finally, polishing the joint of the outer protective layer to make it smooth.

[0016] Compared with the prior art, the method for preparing defects in the outermost tensile armor layer of flexible risers described in this invention has the following advantages: This invention is a method for preparing a sample tube containing defects for flexible risers, which can realize the preparation of defects in the outermost tensile armor layer within existing flexible riser sections, solving the current problem of lacking pre-fabricated defects in the outermost tensile armor layer of flexible risers; the prepared defects can simulate corrosion and fracture of the outermost tensile armor layer of flexible risers. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A flowchart illustrating the method for preparing defects in the outermost tensile armor layer of a flexible riser.

[0019] Figure 2 This is a schematic diagram showing the cutting of the outer protective layer of a flexible riser.

[0020] Figure 3 This is a schematic diagram of machining defects on the outermost tensile armor layer.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Flexible riser; 2. Outermost tensile armor layer; 3. Groove defects; 4. Fracture defects; 5. Hole defects. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, this invention provides a method for preparing defects in the outermost tensile armor layer of a flexible riser, comprising the following steps:

[0026] Step 1: Cut a flexible riser 1 of a predetermined length as the experimental steel pipe substrate;

[0027] Step 2, fix both ends of the flexible riser 1; specifically, use a flexible riser clamping device (or pipe fixing clamping device) or welding method to fix or weld the metal layers of the two ends of the flexible riser 1 together, so as to prevent the armor layer from falling apart and causing damage to the pipe structure during the cutting of the outer protective layer of the flexible riser 1.

[0028] Step 3: Cut the outer protective layer of flexible riser 1;

[0029] First, cut along the outer protective layer of the flexible riser 1, but not exceeding the thickness of the outer protective layer, to form a closed shape; then, remove the cut outer protective layer to expose the outermost tensile armor layer 2, so that defects can be better processed on the outermost tensile armor layer 2; if the outer protective layer of the cut area cannot be removed, soften the outer protective layer by local heating and then remove it.

[0030] Step 4: Process defects on the outermost tensile armor layer 2. Specifically, when processing defects on the outermost tensile armor layer 2, select one or more flat steels of the outermost tensile armor layer 2 to process defects. The defects include hole defects 5, slot defects 3, and fracture defects 4. The hole defects 5 are selected with different diameters and arranged at the same interval. Setting multiple hole defects 5 with different diameters can be better used for subsequent verification of the detection accuracy of non-destructive testing methods. The slot defects 3 are selected with different lengths, widths, and depths and arranged at the same interval. Setting multiple slot defects 3 with different sizes can be better used for subsequent verification of the detection accuracy of non-destructive testing methods. In order to prevent the fracture defects 4 from affecting the signal of the hole defects 5 or the slot defects 3 during subsequent non-destructive testing, the fracture defects 4 are set at different fracture positions of the flat steels of the outermost tensile armor layer 2. That is, the flat steel with fracture defects 4 is not the same flat steel as the flat steel with hole defects 5 or the flat steel with slot defects 3.

[0031] Step 5: Restore the outer protective layer of flexible riser 1.

[0032] First, put the outer protective layer that was removed in step 3 back in its original position;

[0033] Then, the removed outer protective layer and the outer protective layer of the flexible riser 1 are fused together. Specifically, this includes two methods: one is to heat the outer protective layer at the notch to fuse the removed outer protective layer and the outer protective layer of the flexible riser 1 together; the other is to heat a glue rod made of the same material as the outer protective layer, melt the heated end of the glue rod, and drip the glue into the notch to fuse the removed outer protective layer and the outer protective layer of the flexible riser 1 together.

[0034] Finally, polish the joints of the outer protective layer to make them smooth.

[0035] The method described in this invention solves the problem of the lack of a flexible riser outermost tensile armor layer, making it difficult to prefabricate defects. The defects in the outermost tensile armor layer of the flexible riser produced by this invention can effectively simulate corrosion and fracture defects in the armor layer.

[0036] Example 1

[0037] A method for preparing defects in the outermost tensile armor layer of a flexible riser includes the following steps:

[0038] Step 1: Cut a 2-meter-long flexible riser 1 as the experimental steel pipe base, and the outermost tensile armor layer 2 has a cross-sectional dimension of 5mm×10mm;

[0039] Step 2: Secure both ends of the flexible riser 1 using a pipe clamping device;

[0040] Step 3: Cut a 1m x 0.5m piece of the outer protective layer of the flexible riser 1 along the axial direction of the flexible riser 1. After removing the outer protective layer, the outermost tensile armor layer 2 can be seen.

[0041] Step 4: Select a flat steel bar with the outermost tensile armor layer 2 and drill holes of 1mm, 2mm, 3mm, and 4mm respectively to create defects 5; select another flat steel bar with the outermost tensile armor layer 2 and cut grooves of 1mm×1mm×1mm, 1mm×2mm×1mm, 1mm×3mm×1mm, 1mm×4mm×1mm or 1mm×1mm×1mm, 2mm×1mm×1mm, 3mm×1mm×1mm, 4mm×1mm×1mm or 1mm×3mm×1mm, 1mm×3mm×2mm, 1mm×3mm×3mm, 1mm×3mm×4mm respectively to create defects 3; select another flat steel bar with the outermost tensile armor layer and cut it off to form fracture defects 4;

[0042] Step 5: Put the removed outer protective layer back in place, use a hot air blower to heat the cut area to fuse the cuts together, and grind the cut joint smooth after cooling.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing defects in the outermost tensile armor layer of a flexible riser, characterized in that, Includes the following steps: Step 1: Cut a flexible riser (1) of a predetermined length as the experimental steel pipe substrate; Step 2, fix both ends of the flexible riser (1); Step 3, cut the outer protective layer of the flexible riser (1); First, cut along the outer protective layer of the flexible riser (1) without exceeding the thickness of the outer protective layer, cutting it into a closed shape; then, remove the cut outer protective layer to expose the outermost tensile armor layer (2); if the outer protective layer of the cut area cannot be removed, soften the outer protective layer by local heating and then remove it. Step 4: Process defects on the outermost tensile armor layer (2); When processing defects on the outermost tensile armor layer (2), select one or more flat steels of the outermost tensile armor layer (2) to process defects, including hole defects (5), groove defects (3) and fracture defects (4); The hole defects (5) are selected with different diameters and arranged at the same spacing; the groove defects (3) are selected with different lengths, widths and depths and arranged at the same spacing; the fracture defects (4) are selected at the fracture positions of the outermost tensile armor layer (2) flat steel. Step 5: Restore the outer protective layer of the flexible riser (1).

2. The method for preparing defects in the outermost tensile armor layer of a flexible riser according to claim 1, characterized in that: Step 2 specifically involves using a flexible riser clamping device or welding method to fix or weld the metal layers on the two ends of the flexible riser (1) together.

3. The method for preparing defects in the outermost tensile armor layer of a flexible riser according to claim 1, characterized in that: Step 5 includes: first, putting the outer protective layer removed in step 3 back in place; then, heating the outer protective layer at the notch to fuse the removed outer protective layer with the outer protective layer of the flexible riser (1); and finally, polishing the connection point of the outer protective layer to make it flat.

4. The method for preparing defects in the outermost tensile armor layer of a flexible riser according to claim 1, characterized in that: Step 5 includes: first, putting the outer protective layer removed in step 3 back in place; then, heating a glue stick made of the same material as the outer protective layer to melt the heated end of the glue stick and dripping glue into the notch to fuse the removed outer protective layer and the outer protective layer of the flexible riser (1) together; finally, polishing the connection position of the outer protective layer to make it flat.

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