A structure and method for repairing axial defects in oil and gas pipelines

Abstract

This invention relates to the field of oil and gas pipelines, and discloses a structure and method for repairing axial defects in oil and gas pipelines. By applying a filling material between a shaped B-type sleeve liner and the defective part of the oil and gas pipeline, and by pressing the shaped B-type sleeve liner tightly, the filling material is filled annularly between the shaped B-type sleeve liner and the defective part of the oil and gas pipeline. This achieves the control of the gap between the B-type sleeve and the pipeline, effectively suppressing axial defects in the pipeline, increasing the constraint effect of the shaped B-type sleeve liner on the defective part of the pipeline, and under the action of internal pressure, effectively preventing the expansion of axial defects in the oil and gas pipeline, thus greatly improving the repair capability of axial defects in oil and gas pipelines.

Description

Technical Field

[0001] This invention relates to the field of oil and gas pipelines, specifically to a structure and method for repairing axial defects in oil and gas pipelines. Background Technology

[0002] Pipeline transportation is one of the most economical, convenient, and important modes of transporting oil and natural gas. It has advantages such as low cost, large capacity, and high labor productivity. It occupies an extremely important strategic position in the national economy and is widely used in industrial and civilian fields. It is known as the lifeline of the national economy.

[0003] Oil and gas pipelines inevitably develop various defects during construction and operation. If these defects are not dealt with in a timely manner, they may cause fires and explosions, resulting in catastrophic consequences such as huge economic losses, casualties, and environmental pollution. This seriously affects the stable operation of the social economy and endangers people's lives.

[0004] Among various pipeline defects, axial defects pose the most serious threat. Under internal pressure P, the stress on a pipeline axial defect is as follows: Figure 1 As shown, due to the presence of the axial defect, the load-bearing capacity of this part will decrease. Under internal pressure, the metal material at the defect location will first yield, then continue to expand, and finally fracture at the defect location, with the defect expanding to several times its original length, as shown. Figure 2 As shown.

[0005] To prevent more pipeline accidents, defects should be dealt with or repaired promptly during routine pipeline integrity management. Among the many repair methods, the B-type sleeve repair method can withstand not only circumferential loads but also axial and bending loads. Due to the welded ends, it has good sealing performance. Therefore, in relevant repair specifications and standards at home and abroad, the B-type sleeve repair has the most types of defects and can even repair leakage defects, and it is a permanent repair.

[0006] Various domestic and international standards, such as ASME PCC-2, GB / T36701, and SY / T6649, stipulate that the installation clearance between the type B sleeve and the pipe should be controlled within the range of 0~2.5mm. A smaller clearance is better for axial defects in the pipe, as it better inhibits the yield expansion of the defect. However, in practical applications, due to dimensional deviations in both the pipe and the sleeve, it is difficult to control the clearance within a very small range during assembly. In actual applications, the installation clearance between the sleeve and the pipe can sometimes reach around 10mm. With an increased clearance, the restraining effect of the type B sleeve on the defective part of the pipe will be greatly reduced, and under internal pressure, the axial defect may expand. Summary of the Invention

[0007] In order to overcome the defects of the prior art, the present invention aims to provide a structure and method for repairing axial defects in oil and gas pipelines, so as to solve the technical problems of difficulty in controlling the gap between the B-type sleeve and the pipeline and the easy expansion of axial defects under internal pressure in the prior art.

[0008] This invention is achieved through the following technical solution: A repair structure for axial defects in oil and gas pipelines includes a shaped B-type sleeve liner and a filling material. The filling material is annularly coated on the defective portion of the oil and gas pipeline. The shaped B-type sleeve liner is fitted and pressed onto the filling material. Both ends of the shaped B-type sleeve liner are welded to the oil and gas pipeline. The shaped B-type sleeve liner includes an upper liner and a lower liner. The longitudinal sections of both the upper and lower liners are semi-arc structures. The upper and lower liners are fitted and pressed onto the filling material, and the opposite parts of the upper and lower liners are welded and fixed.

[0009] Preferably, the middle section of the upper guard plate is a horizontal structure, and both ends are tapered structures, forming an inclination angle of the upper guard plate transition section at the tapered ends; the filling material is between the middle section of the upper guard plate and the oil and gas pipeline; wherein, the gap between the tapered ends and the oil and gas pipeline is 0~5mm, the gap between the middle section and the oil and gas pipeline is 10mm~15mm, and the inclination angle of the upper guard plate transition section does not exceed 30°.

[0010] Preferably, the middle section of the lower guard plate is a horizontal structure, and both ends are tapered structures, forming an inclination angle of the lower guard plate transition section at the tapered ends; the filling material is between the middle section of the lower guard plate and the oil and gas pipeline; wherein, the gap between the tapered ends and the oil and gas pipeline is 0~5mm, the gap between the middle section and the oil and gas pipeline is 10mm~15mm, and the inclination angle of the lower guard plate transition section does not exceed 30°.

[0011] Preferably, the coating thickness of the filler material on the oil and gas pipeline is 15mm to 20mm.

[0012] Preferably, the axial length center of the filling material is aligned with the axial length center of the defect in the oil and gas pipeline.

[0013] A method for repairing axial defects in oil and gas pipelines, based on the aforementioned structure for repairing axial defects in oil and gas pipelines, includes the following steps: Step 1: Design the length of the irregular B-type sleeve liner according to the size of the axial defect of the pipeline, and divide the irregular B-type sleeve liner into an upper liner and a lower liner, wherein the outer diameters at both ends of the upper liner and the lower liner are smaller than the outer diameter at the middle. Step 2: Apply filler material to the defective part of the oil and gas pipeline. The center of the axial length of the filler material is aligned with the center of the axial length of the defect in the oil and gas pipeline. The length of the filler material is the same as the middle length of the upper and lower protective plates. Step 3: The upper and lower protective plates are fastened together and placed on the filling material at the defective part of the oil and gas pipeline. The upper and lower protective plates are then pressed against the axis of the oil and gas pipeline using a fastening device. The fastening and pressing are stopped when the side walls of the upper and lower protective plates come into contact. At this time, the filling material is filled in the annular space between the upper and lower protective plates and the oil and gas pipeline by the pressing of the upper and lower protective plates, and the excess filling material is pressed to the outside of the upper and lower protective plates. Step 4: Before the filler material cures, clean the filler material around the axial side welds and circumferential fillet welds of the upper and lower protective plates. After the filler material cures, weld the axial side welds and circumferential fillet welds of the upper and lower protective plates in sequence to complete the axial defect repair work of the oil and gas pipeline.

[0014] Preferably, the properties of the filler material after curing are as follows: high temperature resistance greater than 1000℃, compressive strength greater than 200MPa, elastic modulus greater than 70GPa, Poisson's ratio greater than 0.19, and shrinkage rate less than 0.005%.

[0015] Furthermore, the filler material is in the form of putty before it cures.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a structure for repairing axial defects in oil and gas pipelines. By applying a filling material between a shaped B-type sleeve liner and the defective part of the oil and gas pipeline, and by pressing the shaped B-type sleeve liner tightly, the filling material is filled annularly between the shaped B-type sleeve liner and the defective part of the oil and gas pipeline. This achieves the control of the gap between the B-type sleeve and the pipeline, effectively suppressing axial defects in the pipeline, increasing the constraint effect of the shaped B-type sleeve liner on the defective part of the pipeline, and under the action of internal pressure, effectively preventing the expansion of axial defects in the oil and gas pipeline, thus greatly improving the repair capability of axial defects in oil and gas pipelines.

[0017] Furthermore, the middle section of the upper protective plate is horizontal, and both ends are tapered, forming an inclined transition section at the tapered ends. The middle section of the lower protective plate is also horizontal, with tapered ends at both ends, forming an inclined transition section at the tapered ends. This design effectively wraps the filler material applied to the oil and gas pipeline. The tapered ends of both the upper and lower protective plates facilitate welding them to the oil and gas pipeline, improving the ability to repair defects in the oil and gas pipeline.

[0018] Furthermore, the filling material is coated with a thickness of 15mm to 20mm on the oil and gas pipeline, which facilitates the filling material to fill the gap between the upper and lower protective plates and the oil and gas pipeline after the upper and lower protective plates are pressed and fastened, thereby improving the repair capability of defective parts of the oil and gas pipeline.

[0019] Furthermore, the axial length center of the filling material is aligned with the axial length center of the defect in the oil and gas pipeline, which can effectively repair the defect in the oil and gas pipeline by pressing the filling material with the irregular B-type sleeve protective plate.

[0020] This invention also provides a method for repairing axial defects in oil and gas pipelines. By applying a filling material between the defective part of the oil and gas pipeline and the shaped B-type sleeve liner, the filling material can fill all the gaps between the defective part of the oil and gas pipeline and the shaped B-type sleeve liner due to its very small curing shrinkage rate. The force generated by the pipeline defect under internal pressure will be transmitted to the external steel liner through the cured filling material, and the yield expansion of the axial defect of the pipeline will be well suppressed, thereby achieving the purpose of repairing the axial defect of the pipeline. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the stress condition of a pipe with axial defects under internal pressure in the prior art; Figure 2 This is a schematic diagram illustrating the rupture of a pipe with axial defects under internal pressure in the prior art. Figure 3 This is a schematic diagram of the irregular B-type sleeve guard plate in this invention; Figure 4 for Figure 3 Side view; Figure 5 This is a schematic diagram of the application of filling material to the defective parts of the pipeline in this invention; Figure 6 This is a schematic diagram of the installation and fastening of the irregular B-type sleeve guard plate in this invention; Figure 7 This is a schematic diagram of the axial defect repair structure for oil and gas pipelines in this invention.

[0022] In the figure: 1-Irregular B-type sleeve liner; 2-Oil and gas pipeline; 3-Filling material; 11-Upper liner; 12-Lower liner; 111-Inclination angle of the transition section of the upper liner; 121-Inclination angle of the transition section of the lower liner. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings: The purpose of this invention is to provide a structure and method for repairing axial defects in oil and gas pipelines, so as to solve the technical problems in the prior art where it is difficult to control the gap between the B-type sleeve and the pipeline and the axial defects are easy to expand under internal pressure.

[0026] Specifically, the axial defect repair structure for this oil and gas pipeline is based on... Figure 7 As shown, it includes a shaped B-type sleeve guard plate 1 and a filling material 3; the filling material 3 is annularly coated on the defective part of the oil and gas pipeline 2, the shaped B-type sleeve guard plate 1 is sleeved and pressed on the filling material 3, and the two ends of the shaped B-type sleeve guard plate 1 are respectively welded to the oil and gas pipeline 2. The shaped B-type sleeve guard plate 1 includes an upper guard plate 11 and a lower guard plate 12; the longitudinal section of the upper guard plate 11 and the lower guard plate 12 are both semi-arc structures, the upper guard plate 11 and the lower guard plate 12 are respectively fastened and pressed on the filling material 3, and the opposite parts of the upper guard plate 11 and the lower guard plate 12 are welded and fixed.

[0027] Preferably, the middle section of the upper guard plate 11 is a horizontal structure, and both ends are constricted structures, forming an inclination angle 111 at the constricted ends; the filling material 3 is between the middle section of the upper guard plate 11 and the oil and gas pipeline 2; wherein, the gap between the constricted ends and the oil and gas pipeline 2 is 0~5mm, the gap between the middle section and the oil and gas pipeline 2 is 10mm~15mm, and the inclination angle 111 of the upper guard plate transition section does not exceed 30°.

[0028] Preferably, the middle section of the lower guard plate 12 is a horizontal structure, and both ends are tapered structures, forming a lower guard plate transition section with an inclination angle of 121 at the tapered ends; the filling material 3 is between the middle section of the lower guard plate 12 and the oil and gas pipeline 2; wherein, the gap between the tapered ends and the oil and gas pipeline 2 is 0~5mm, the gap between the middle section and the oil and gas pipeline 2 is 10mm~15mm, and the inclination angle 121 of the lower guard plate transition section does not exceed 30°.

[0029] Preferably, the coating thickness of the filler material 3 on the oil and gas pipeline 2 is 15mm to 20mm.

[0030] Preferably, the axial length center of the filling material 3 is aligned with the axial length center of the defect in the oil and gas pipeline 2.

[0031] This invention also provides a method for repairing axial defects in oil and gas pipelines, based on the aforementioned structure for repairing axial defects in oil and gas pipelines, comprising the following steps: Step 1: Design the length of the irregular B-type sleeve guard plate 1 according to the size of the axial defect of the pipeline, and divide the irregular B-type sleeve guard plate 1 into an upper guard plate 11 and a lower guard plate 12, wherein the outer diameters at both ends of the upper guard plate 11 and the lower guard plate 12 are smaller than the outer diameter at the middle. Step 2: Apply filler material 3 to the defective part of oil and gas pipeline 2. The center of the axial length of filler material 3 is aligned with the center of the axial length of the defect in oil and gas pipeline 2. The length of filler material 3 is consistent with the middle length of upper protective plate 11 and lower protective plate 12. Step 3: The upper protective plate 11 and the lower protective plate 12 are fastened together and placed on the filling material 3 at the defective part of the oil and gas pipeline 2. The upper protective plate 11 and the lower protective plate 12 are pressed towards the axis of the oil and gas pipeline 2 by the fastening device. The fastening and pressing is stopped when the side walls of the upper protective plate 11 and the lower protective plate 12 come into contact. At this time, the filling material 3 is filled in the annular space between the upper protective plate 11 and the lower protective plate 12 and the oil and gas pipeline 2 by the pressing of the upper protective plate 11 and the lower protective plate 12, and the excess filling material 3 is pressed to the outside of the upper protective plate 11 and the lower protective plate 12. Step 4: Before the filler material 3 cures, clean the filler material around the axial side welds and circumferential fillet welds of the upper guard plate 11 and the lower guard plate 12. After the filler material 3 cures, weld the axial side welds of the upper guard plate 11 and the lower guard plate 12 and weld the circumferential fillet welds in sequence to complete the axial defect repair work of the oil and gas pipeline.

[0032] Preferably, the filler material 3 is in the form of putty, and the properties of the filler material 3 after curing are as follows: high temperature resistance should be greater than 1000℃, compressive strength should be greater than 200MPa, elastic modulus should be greater than 70GPa, Poisson's ratio should be greater than 0.19, and shrinkage rate should be less than 0.005%.

[0033] After the above-mentioned technical measures are implemented in this invention, the filling material, after curing, has a very small curing shrinkage rate. Therefore, it can fill all the gaps in the steel pipe and the sleeve. The force generated by the defective part of the pipe under internal pressure will be transmitted to the external steel protective plate through the cured filling material. The yield expansion of the axial defective part of the pipe will be well suppressed, thereby achieving the purpose of repairing the axial defect of the pipe.

[0034] Example This embodiment repairs axial defects in oil and gas pipelines using a method that includes the following steps: Step 1: Design the length of the irregular sleeve based on the axial defect size of the pipe. The sleeve consists of upper and lower protective plates, with smaller outer diameters at both ends and larger outer diameters in the middle. Figure 3 and Figure 4 As shown. The gap between the two ends of the sleeve and the pipe is 3mm, the gap between the middle of the sleeve and the pipe is 15mm, and the inclination angle of the transition section is 30°.

[0035] Step 2: Apply filler material to the pipe defect, aligning the center of the filler material's axial length with the center of the defect's axial length, and ensuring the length matches the middle length of the sleeve. The thickness t of the filler material coating is 20mm. Figure 5 As shown. The filler material is in the form of putty, and its properties after curing are as follows: high temperature resistance of 1100℃, compressive strength of 230MPa, elastic modulus of 70GPa, Poisson's ratio of 0.20, and shrinkage rate of 0.005%.

[0036] Step 3: Cover the filler material applied to the defective area of ​​the steel pipe with the upper and lower protective plates. The center of the length of the protective plates should be aligned with the center of the length of the filler material. Figure 6 As shown.

[0037] Step 4: Use a fastening device to press the upper and lower protective plates towards the pipe axis. Stop fastening when the sides of the upper and lower protective plates contact each other. During the fastening process, the applied fastening force F should be uniform and symmetrical to ensure consistent gaps. The filling material should be uncured and have good fluidity. Figure 5 As shown. The annular space between the sleeve and the steel pipe can be filled by the compression of the upper and lower protective plates, and the excess filling material is squeezed to the outside.

[0038] Step 5: Before the filler material cures, clean the filler material around the axial weld and circumferential fillet weld to avoid affecting the welding. After the filler material cures, first weld the axial weld, then weld the circumferential fillet weld, as follows. Figure 7 As shown In summary, this invention provides a structure and method for repairing axial defects in oil and gas pipelines. By applying a filling material between the shaped B-type sleeve liner and the defective part of the oil and gas pipeline, and by pressing the shaped B-type sleeve liner tightly, the filling material is filled annularly between the shaped B-type sleeve liner and the defective part of the oil and gas pipeline. This achieves the control of the gap between the B-type sleeve and the pipeline, effectively suppressing axial defects in the pipeline, increasing the constraint effect of the shaped B-type sleeve liner on the defective part of the pipeline, and under the action of internal pressure, effectively preventing the expansion of axial defects in the oil and gas pipeline, thus greatly improving the repair capability of axial defects in oil and gas pipelines.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method of repairing an axial defect in an oil and gas pipeline, the method comprising: Includes the following steps: Step 1: Design the length of the irregular B-type sleeve guard plate (1) according to the size of the axial defect of the pipeline, and divide the irregular B-type sleeve guard plate (1) into an upper guard plate (11) and a lower guard plate (12), wherein the outer diameters at both ends of the upper guard plate (11) and the lower guard plate (12) are smaller than the outer diameter at the middle. Step 2: Apply filler material (3) to the defect of the oil and gas pipeline (2). The center of the axial length of the filler material (3) is aligned with the center of the axial length of the defect of the oil and gas pipeline (2). The length of the filler material (3) is consistent with the middle length of the upper guard plate (11) and the lower guard plate (12). Step 3: The upper protective plate (11) and the lower protective plate (12) are fastened together and placed on the filling material (3) of the defective part of the oil and gas pipeline (2). The upper protective plate (11) and the lower protective plate (12) are pressed towards the axis of the oil and gas pipeline (2) by the fastening device. The fastening and pressing is stopped when the side walls of the upper protective plate (11) and the lower protective plate (12) come into contact. At this time, the filling material (3) is filled in the annular space between the upper protective plate (11) and the lower protective plate (12) and the oil and gas pipeline (2) by the pressing of the upper protective plate (11) and the lower protective plate (12), and the excess filling material (3) is pressed to the outside of the upper protective plate (11) and the lower protective plate (12). Step 4: Before the filler material (3) is cured, clean the filler material around the axial side welds and circumferential fillet welds of the upper guard plate (11) and the lower guard plate (12). After the filler material (3) is cured, weld the axial side welds of the upper guard plate (11) and the lower guard plate (12) and weld the circumferential fillet welds in sequence to complete the axial defect repair work of the oil and gas pipeline.

2. The method of claim 1, wherein, The properties of the filler material (3) after curing are as follows: high temperature resistance should be greater than 1000℃, compressive strength should be greater than 200MPa, elastic modulus should be greater than 70GPa, Poisson's ratio should be greater than 0.19, and shrinkage rate should be less than 0.005%.

3. The method of claim 1, wherein, The filler material (3) is in the form of putty before curing.

4. An oil and gas pipeline axial defect repair structure, characterized by, The method for repairing axial defects in an oil and gas pipeline as described in any one of claims 1-3 includes a shaped B-type sleeve guard plate (1) and a filling material (3); the filling material (3) is circumferentially coated on the defective part of the oil and gas pipeline (2); the shaped B-type sleeve guard plate (1) is sleeved and pressed on the filling material (3); the two ends of the shaped B-type sleeve guard plate (1) are respectively welded to the oil and gas pipeline (2); the shaped B-type sleeve guard plate (1) includes an upper guard plate (11) and a lower guard plate (12); the longitudinal section of the upper guard plate (11) and the lower guard plate (12) are both semi-arc structures; the upper guard plate (11) and the lower guard plate (12) are respectively fastened and pressed on the filling material (3); and the upper guard plate (11) and the lower guard plate (12) are welded and fixed at their opposite positions.

5. An axial defect repair structure for an oil and gas pipeline as defined in claim 4, wherein, The middle section of the upper guard plate (11) is a horizontal structure, and the two ends are constricted structures, forming an inclination angle (111) of the upper guard plate transition section at the constricted end; the filling material (3) is between the middle section of the upper guard plate (11) and the oil and gas pipeline (2); wherein, the gap between the constricted end and the oil and gas pipeline (2) is 0~5mm, the gap between the middle section and the oil and gas pipeline (2) is 10mm~15mm, and the inclination angle (111) of the upper guard plate transition section does not exceed 30°.

6. An oil and gas pipeline axial defect repair structure according to claim 4, wherein, The middle section of the lower guard plate (12) is a horizontal structure, and the two ends are constricted structures, forming a lower guard plate transition section inclination angle (121) at the constricted end; the filling material (3) is between the middle section of the lower guard plate (12) and the oil and gas pipeline (2); wherein, the gap between the constricted end and the oil and gas pipeline (2) is 0~5mm, the gap between the middle section and the oil and gas pipeline (2) is 10mm~15mm, and the lower guard plate transition section inclination angle (121) does not exceed 30°.

7. The structure for repairing axial defects of an oil and gas pipeline according to claim 4, wherein The coating thickness of the filler material (3) on the oil and gas pipeline (2) is 15mm to 20mm.

8. The structure for repairing axial defects of an oil and gas pipeline according to claim 4, wherein The axial length center of the filling material (3) is aligned with the axial length center of the defect in the oil and gas pipeline (2).

Images