A third-party damage simulation method for buried pipelines

Abstract

This application discloses a method for simulating third-party damage to buried pipelines, which relates to the field of pipeline testing technology. Specifically, a wedge-shaped mold is used to press different indentations on the surface of a first specimen using different simulated pressure loads. The damage parameters of each indentation are then obtained, and a mapping relationship model between the simulated pressure load and the damage parameters is established based on the corresponding relationship between the damage parameters of each indentation and each simulated pressure load. The damage parameters of the third-party damage on the pipe to be tested are then obtained and input into the above mapping relationship model to obtain the corresponding simulated pressure load. The corresponding simulated pressure load is then applied to the surface of a second specimen to obtain an experimental specimen having an indentation simulating the third-party damage. This method is simple, convenient, and easy to implement. It can accurately simulate the on-site third-party damage conditions of buried pipelines, facilitate hydrogen embrittlement performance testing of different third-party damages, and establish a correlation between damage parameters and hydrogen embrittlement performance of the pipe.

Description

Technical Field

[0001] The present application relates to the technical field of pipeline testing, and in particular to a method for simulating third-party damage to buried pipelines. Background Art

[0002] In recent years, my country has seen rapid development in infrastructure construction across transportation, postal and telecommunications, energy and power, and real estate development. These construction activities can easily cause third-party damage, such as scratches or dents, to nearby oil and gas pipelines. This third-party damage causes irreversible plastic deformation in the pipelines, which is essentially the proliferation and movement of dislocations. This alters hydrogen permeation behavior and hydrogen embrittlement susceptibility. Currently, the mechanisms by which third-party damage influences pipeline hydrogen embrittlement performance remain largely unknown, posing a serious threat to the safe operation of oil and gas pipelines.

[0003] Therefore, there is an urgent need to provide a reliable simulation method to accurately simulate the third-party damage conditions of buried pipelines, facilitate the hydrogen embrittlement performance testing of different third-party damages, establish the correlation between damage parameters and hydrogen embrittlement performance of pipes, and evaluate the hydrogen embrittlement risk of buried pipelines with third-party damage. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for simulating third-party damage to buried pipelines, accurately simulate the on-site third-party damage conditions of buried pipelines, facilitate hydrogen embrittlement performance testing for different third-party damages, establish a correlation between damage parameters and hydrogen embrittlement performance of pipes, and evaluate the hydrogen embrittlement risk of buried pipelines with third-party damage.

[0005] To achieve the above technical objectives, the present application provides a method for simulating third-party damage to buried pipelines, which is characterized by comprising the steps of:

[0006] S1, applying multiple different simulated pressure loads on the surface of the first specimen to obtain multiple different indentations;

[0007] S2, obtaining damage parameters of each of the indentations, and establishing a mapping relationship model between the simulated pressure load and the damage parameters based on the corresponding relationship between the damage parameters of each of the indentations and each of the simulated pressure loads;

[0008] S3, obtaining damage parameters of third-party damage on the pipe to be tested and inputting them into the mapping relationship model to obtain corresponding simulated pressure load;

[0009] S4, applying the corresponding simulated pressure load on the surface of the second sample to obtain an experimental sample with an indentation simulating the third-party damage.

[0010] Furthermore, the indentation is formed by pressing with a wedge-shaped mold, and the simulated pressure load is between 10N and 10000N.

[0011] Furthermore, the damage parameters include pit depth and grain deformation zone range.

[0012] Furthermore, the second sample is a standard tensile rod.

[0013] It can be seen from the above technical solutions that the third-party damage simulation method for buried pipelines designed in this application specifically first applies multiple different simulated pressure loads on the surface of the first sample to obtain multiple different indentations; then obtains the damage parameters of each indentation, and based on the correspondence between the damage parameters of each indentation and each simulated pressure load, establishes a mapping relationship model between the simulated pressure load and the damage parameters; then obtains the damage parameters of the third-party damage on the pipe to be tested, and inputs them into the above mapping relationship model to obtain the simulated pressure load corresponding to the third-party damage; after determining the simulated pressure load corresponding to the third-party damage, applies the corresponding simulated pressure load on the surface of the second sample to obtain an experimental sample with an indentation simulating the third-party damage. This method of the present application is simple, convenient, and easy to implement. It can accurately simulate the third-party damage working conditions of the buried pipeline on-site, facilitates hydrogen embrittlement performance testing of different third-party damages, and establishes a correlation between damage parameters and hydrogen embrittlement performance of the pipe. According to the hydrogen embrittlement performance, the safety risk level of the third-party damage can be clarified, which is of great significance to the safety evaluation of oil and gas pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0015] Figure 1 This is a flow chart of a third-party damage simulation method for buried pipelines provided in this application;

[0016] Figure 2 This is a further flow chart of step S5 of a third-party damage simulation method for buried pipelines provided in this application;

[0017] Figure 3 Schematic diagram of the standard tensile rod structure;

[0018] Figure 4a This is the metallographic image of the pit depth measurement of the indentation under 2500N load conditions;

[0019] Figure 4b Metallographic image of the grain deformation zone measured for the indentation under a load of 2500N. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions of the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present application, not all of them. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the embodiments of the present application.

[0021] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0022] In the description of the embodiments of the present application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, replaceable connections, or integral connections. They can also refer to mechanical connections or electrical connections. They can also refer to direct connections or indirect connections through an intermediate medium. They can also refer to internal connections between two components. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0023] The embodiment of the present application discloses a method for simulating third-party damage to a buried pipeline.

[0024] See also Figure 1 As shown, an embodiment of a third-party damage simulation method for buried pipelines provided in the embodiments of the present application includes:

[0025] step:

[0026] S1, applying a plurality of different simulated pressure loads on the surface of the first sample to obtain a plurality of different indentations. It should be noted that this step is to apply different simulated pressure loads to press different indentations on the surface of the first sample.

[0027] S2: Obtain damage parameters for each indentation, and establish a mapping relationship model between the simulated pressure load and the damage parameters based on the corresponding relationship between the damage parameters of each indentation and each simulated pressure load. It should be noted that the mapping relationship model is derived from the corresponding relationship between the damage parameters of each indentation and each simulated pressure load.

[0028] S3, obtain the damage parameters of the third-party damage on the pipe to be tested and input them into the mapping relationship model to obtain the corresponding simulated pressure load. It should be noted that, with regard to the acquisition of the damage parameters of the third-party damage on the pipe to be tested, specifically, sampling the third-party damage on the pipe to be tested on site, and then measuring the damage parameters of the sampled third-party damage, that is, obtaining the damage physical characteristic parameters of the third-party damage. The execution subject of this step can be a corresponding data processing module, including but not limited to mobile phones and computers with data processing capabilities. By inputting the damage parameters of the third-party damage into the mapping relationship model, the simulated pressure load data corresponding to the third-party damage can be calculated.

[0029] S4, applying a corresponding simulated pressure load on the surface of the second sample to obtain an experimental sample with an indentation simulating third-party damage. In this application, the first sample and the second sample are both made of the same material as the pipe to be tested.

[0030] This method is simple, convenient, and easy to implement. It can accurately simulate the conditions of third-party damage in buried pipelines, facilitate hydrogen embrittlement performance testing for different third-party damage conditions, and establish a correlation between damage parameters and the hydrogen embrittlement performance of pipe materials. Furthermore, based on the hydrogen embrittlement performance, the safety risk level of third-party damage can be determined, which is of great significance for the safety assessment of oil and gas pipelines.

[0031] The above is the first embodiment of a third-party damage simulation method for buried pipelines provided by the embodiment of the present application. The following is the second embodiment of a third-party damage simulation method for buried pipelines provided by the embodiment of the present application. For details, please refer to Figures 1 to 3 、 Figure 4a as well as Figure 4b .

[0032] Based on the solution of the above embodiment 1:

[0033] Furthermore, as for the preparation of indentations, they can be formed by pressing with a wedge-shaped mold, and the simulated pressure load can be between 10N and 10,000N. Of course, other related devices and equipment can also be used to prepare indentations, without limitation. Taking a wedge-shaped mold as an example, S1 specifically uses a wedge-shaped mold to press different indentations on the surface of the first specimen using different simulated pressure loads to achieve damage simulation under different forces.

[0034] Furthermore, the damage parameters include the pit depth and the range of the grain deformation zone. That is, the damage parameters to be measured in this application include the pit depth and the range of the grain deformation zone.

[0035] Furthermore, in order to facilitate the subsequent hydrogen embrittlement test of the prepared experimental sample, the second sample can be a standard tensile rod, and its specific structure is as follows: Figure 3As shown, both ends also have threaded structures to facilitate connection with the tensile machine during subsequent tensile testing. Taking this as an example, the S4 specifically applies a corresponding simulated pressure load at the center position of the gauge length section on the surface of the standard tensile rod.

[0036] The following slow tensile tests can be performed based on the third-party damage simulation method:

[0037] S5: Perform slow tensile tests on the experimental and control specimens to obtain the hydrogen embrittlement sensitivity coefficients of the experimental and control specimens, respectively. The control specimen is a standard tensile rod without an indentation. It should be noted that the control specimen is a standard tensile rod simulating a buried pipe without third-party damage. Specifically, the test is conducted on both an undamaged standard tensile rod and an indented standard tensile rod.

[0038] S6 compares the hydrogen embrittlement sensitivity coefficients of the experimental samples with those of the control samples to determine the impact of third-party damage on the hydrogen embrittlement performance of the pipe. Based on the impact results, the safety risk level of third-party damage is determined. This allows for a more accurate assessment of buried pipelines with third-party damage, enabling more appropriate maintenance measures to be implemented for these buried pipelines.

[0039] like Figure 2 As shown in the figure, for the slow tensile test of the sample, the details are as follows:

[0040] S51, coating the silicone on the standard tensile rod to be tested and leaving a predetermined exposed area. It should be noted that the coating of the silicone can be performed manually or by a corresponding coating device, without limitation.

[0041] S52: Pass the coated standard tensile rod through a dielectric box with the exposed area positioned within the dielectric box. The dielectric box is filled with a soil simulating solution. It should be noted that the soil simulating solution is prepared by drying and grinding the obtained on-site soil into a fine powder, which is then mixed with water in a specific ratio, preferably a 1:1 ratio, to form a simulated solution.

[0042] S53: Connect the three-electrode system consisting of the standard tensile rod, auxiliary electrode, and reference electrode passing through the dielectric box to a potentiostat, forming a complete closed circuit with the soil simulation solution in the dielectric box. In this step, the cathodic protection potential of the potentiostat is set by adjusting the potentiostat control panel. The reference electrode is a CSE (copper-copper sulfate electrode). The cathodic protection potential can be between -0.85V and -1V, specifically -1V.

[0043] S54, connect the stretching machine to the two ends of the standard stretching rod passing through the medium box and perform slow stretching. It should be noted that after the stretching ends of the stretching machine are connected to the two ends of the standard stretching rod, the stretching machine can be controlled to stretch the experimental sample. When performing the slow stretching test, the strain rate is preferably 10 -6 s -1 .

[0044] S55, obtaining the cross-sectional shrinkage of the standard stretched rod after slow stretching, and inputting the obtained cross-sectional shrinkage into a preset hydrogen embrittlement sensitivity coefficient calculation formula to obtain the corresponding hydrogen embrittlement sensitivity coefficient. It should be noted that the preset hydrogen embrittlement sensitivity coefficient calculation formula is:

[0045] Hydrogen embrittlement sensitivity coefficient = (section reduction 无损伤空拉试样 - Area reduction 土壤+阴保 ) / area reduction 无损伤空拉试样 ×100%, where the cross-sectional shrinkage is 无损伤空拉试样 The cross-sectional shrinkage is the ratio of the cross-sectional shrinkage measured by the slow tensile test of the undamaged standard tensile rod in air. 土壤+阴保 It is the cross-sectional shrinkage rate measured in step S54.

[0046] Furthermore, in order to improve the reliability of the slow tensile test, two specimens were prepared for each pressure load, that is, two repeated specimens were prepared under each pressure load condition.

[0047] Based on the solution of the second embodiment above, when the simulated pressure load corresponding to the actual third-party damage is known (taking two third-party damage locations as an example, and corresponding simulated pressure loads of 1000N and 2500N respectively), the experimental process is as follows:

[0048] 1. X80 tubing was prepared into standard tensile bars with a gauge section of φ5mm x 25mm. Using a wedge-shaped die, indentations were made at the center of the corresponding gauge sections on the surface of the standard tensile bars under loads of 1000N and 2500N, respectively, to simulate damage under different forces. During this process, two test specimens were prepared under each load condition, resulting in two test specimens each under a 1000N load and a 2500N load.

[0049] 2. Select an experimental specimen under each load, observe the metallographic structure of the simulated damage (indentation), measure the pit depth and grain deformation zone range corresponding to the simulated damage, and judge whether the measured damage physical characteristic parameters meet the preset range error with the actual corresponding third-party damage physical characteristic parameters to ensure that the prepared experimental specimen is accurate.

[0050] 3. Select another experimental sample and a control sample under each load to conduct a slow tensile test. Specifically, take the experimental sample as an example, seal the experimental sample with silicone, and expose 1cm 2 The test specimen has an M10mm×16mm threaded structure at both ends and is installed between the upper and lower chucks of the tensile machine (the upper and lower chucks provide the tensile load). At the same time, the test specimen is passed through a medium box, in which a soil simulation solution that can simulate the soil environment is placed.

[0051] 4. Connect the three-electrode system consisting of the standard tensile rod (working electrode), auxiliary electrode, and reference electrode to the potentiostat, forming a complete closed circuit with the dielectric in the dielectric box. Adjust the potential parameters on the potentiostat control panel to set the cathodic protection potential to -1.0V.

[0052] 5. Carry out slow tensile test and measure the cross-sectional shrinkage of experimental specimens and control specimens respectively.

[0053] During the above experimental process, a tensile test of a control sample in an empty tensile state was added, that is, a tensile test with air in the medium box.

[0054] The data obtained based on the above experiments are shown in the following table:

[0055]

[0056] As shown in the table above, under the conditions of this simulated soil solution and cathodic protection potential, the hydrogen embrittlement sensitivity coefficient under undamaged conditions is 20.1%, while under third-party damage conditions with loads of 1000N and 2500N, the coefficients are 60.7% and 82.5%, respectively, both significantly greater than 35%. This indicates that the 1000N and 2500N loads correspond to third-party damaged pipelines, indicating a high risk of hydrogen embrittlement. The fracture surfaces of the slow tensile test specimens exhibit brittle fracture characteristics, indicating a low pipeline safety rating and requiring prompt repair or replacement. Furthermore, to ensure safe pipeline operation, the total depth of third-party damage should be limited to 365μm.

[0057] The above is a detailed introduction to a third-party damage simulation method for buried pipelines provided by this application. For those skilled in the art, based on the ideas of the embodiments of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A third-party damage simulation method for buried pipelines, characterized in that: Including steps: S1, applying multiple different simulated pressure loads on the surface of the first specimen to obtain multiple different indentations; S2, obtaining damage parameters of each of the indentations, and establishing a mapping relationship model between the simulated pressure load and the damage parameters based on the corresponding relationship between the damage parameters of each of the indentations and each of the simulated pressure loads, wherein the damage parameters include the pit depth and the range of the grain deformation zone; S3, obtaining damage parameters of third-party damage on the pipe to be tested and inputting them into the mapping relationship model to obtain corresponding simulated pressure load; S4, applying the corresponding simulated pressure load on the surface of the second sample to obtain an experimental sample with an indentation simulating the third-party damage.

2. A third-party damage simulation method for buried pipelines according to claim 1, characterized in that: The indentation is formed by pressing with a wedge-shaped die, and the simulated pressure load is between 10N and 10000N.

3. A third-party damage simulation method for buried pipelines according to claim 1, characterized in that: The second specimen is a standard tensile bar.

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