Method for acquiring overall stress state of crossing section of product oil pipeline

Abstract

The invention discloses a method for acquiring the overall stress state of a product oil pipeline crossing section, which comprises the following steps of: firstly, collecting the pipe diameter, span, wall thickness, material, yield strength and other basic and field information of a pipeline, and completing early-stage preparation; then, contact type coercive force-stress detection is conducted on a ground pipeline (such as a buried pipeline or a crossing pipeline in-out soil section), the number of circumferential detection points is determined according to a formula related to the pipe diameter, each point is detected for three times and averaged, then stress values of the detection points are averaged to obtain section stress, the operation is repeated, and the section stress of a pipeline with the length of at least 2 m is detected every 10 cm; obtaining a foundation stress condition; performing non-contact weak magnetic detection on the pipeline to obtain a magnetic signal, and performing inversion in combination with the stress condition of the pipeline to obtain an inversion model of the weak magnetic signal and the stress of the pipeline; and finally, carrying non-contact weak magnetic detection equipment by using an unmanned aerial vehicle, and detecting the spanning pipeline according to the inversion model to obtain the overall stress distribution condition of the spanning pipeline. Through strong and weak magnetism combined detection, stress conditions of pipelines made of different materials can be obtained, the overall stress condition of the spanning pipeline can be obtained on the ground without personnel reaching the periphery of the pipeline, and safe and stable operation of a pipeline system is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas pipeline detection, and particularly relates to a method for obtaining stress overall state of product oil pipeline crossing section. BACKGROUND

[0002] As the core conveying carrier of oil and natural gas, the safe and stable operation of the pipeline is directly related to the industrial production efficiency, people's livelihood guarantee and ecological environment safety. Among them, the crossing section pipeline is subjected to complex loads such as medium pressure, self weight, wind load, temperature change, earthquake action, foundation settlement and third party disturbance, and stress concentration is easily generated, which becomes the key risk point in the pipeline system. Therefore, it is urgent to obtain the stress overall state of the crossing section pipeline. However, due to the influence of the crossing structure, personnel cannot reach the periphery of the pipeline. The traditional stress acquisition methods such as ultrasonic stress detection have certain limitations, and an efficient technical method for obtaining the stress overall state of the crossing section pipeline is needed to ensure the safe and stable operation of the pipeline system. SUMMARY

[0003] In view of the above problems, the present application provides a method for obtaining stress overall state of product oil pipeline crossing section. By the stress detection method combining strong and weak magnetism, the ground pipeline is detected by contact type detection through the coercive force-stress detection on the ground, and the basic stress condition of the pipeline is obtained. The magnetic signal of the pipeline is obtained by using non-contact weak magnetic detection. According to the stress condition of the pipeline, the magnetic signal obtained by the weak magnetic detection is inverted to obtain the inversion model of the weak magnetic signal and the stress of the pipeline. Then, the stress of the crossing pipeline is detected by using the unmanned aerial vehicle carrying the non-contact weak magnetic detection device, and the overall stress condition of the crossing pipeline can be obtained on the ground.

[0004] The method can obtain the stress condition of the pipeline with different materials, and according to the collected weak magnetic signal, the overall stress level of the pipeline can be inverted. It should be pointed out that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs. The main steps of the method for obtaining stress overall state of product oil pipeline crossing section are as follows:

[0005] Main steps

[0006] S1, data collection, collect pipeline basic information and field information, including: pipe diameter, pipeline span, wall thickness, pipeline material, yield strength. Complete the preliminary work of the method for obtaining stress overall state of product oil pipeline crossing section

[0007] S2, ground pipeline stress condition acquisition, contact coercivity-stress detection is carried out on the ground pipeline (such as buried pipeline or crossing pipeline entering and exiting the soil section), and stress detection is carried out on n circumferential directions of the pipeline. The number of detection points n is related to the pipe diameter, and the calculation method is shown in formula (1). Each point is detected 3 times, and the average of three times is taken as the detection result; the stress values of the n detection points are averaged to obtain the stress value of the pipeline section at this point. Repeat the operation, and detect the stress of at least 2m long pipeline every 10cm, and obtain the pipeline foundation stress condition.

[0008]

[0009] In the formula: n is the number of detection points; [ ] is the integral symbol; d is the pipe diameter, mm.

[0010] S3, the pipeline is detected by non-contact weak magnetic detection, the weak magnetic signal of the pipeline is obtained, the magnetic signal obtained by the weak magnetic detection is inverted according to the pipeline stress condition, and the inversion model of the weak magnetic signal and the pipeline stress is obtained. As shown in formula (2).

[0011]

[0012] In the formula: σ is the stress value of the pipeline, MPa; is the yield strength of the pipeline, MPa; G is the magnetic signal of the pipeline; A is the material coefficient of the pipeline.

[0013] S4, according to the inversion model of the weak magnetic signal and the pipeline stress, the non-contact weak magnetic detection equipment is carried on the unmanned aerial vehicle, the crossing pipeline is detected, and the overall stress distribution of the crossing pipeline is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the examples of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only designed for some embodiments of the present application, and are not limited to the present application.

[0015] Figure 1 It is a schematic diagram of the contact coercivity-stress detection result of the crossing pipeline entering and exiting the soil section in the examples of the present application

[0016] Figure 2 It is a schematic diagram of the pipeline magnetic signal obtained in the examples of the present application

[0017] Figure 3 It is a schematic diagram of the overall stress distribution of the crossing pipeline in the examples of the present application DETAILED EMBODIMENT

[0018] For the purposes of making the objects, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings understood by persons having ordinary skills in the art to which the present disclosure belongs. The clock directions and the x, y, and z directions used in the present application are only used to represent the relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship can also change accordingly. The present application will be further described below with reference to the drawings and embodiments.

[0019] S1, in one embodiment, data collection, collection of pipeline basic information and field information, where the cross product oil pipeline, pipeline material for X60 steel, pipeline diameter is 417 mm, pipeline wall thickness is 7.7 mm, pipeline yield strength is 415 MPa, pipeline span is 40 m.

[0020] S2, in one embodiment, the ground pipeline stress situation is obtained, the contact coercivity-stress detection is performed on the earth section of the ground pipeline crossing pipeline, the stress is calculated by formula (3), and the stress of four circumferential directions of the pipeline is detected. Each point is detected three times, and the average value of three times is taken as the detection result; the stress values of the four detection points are averaged to obtain the stress value of the pipeline section. Repeat the operation, and the stress of the pipeline is detected every 10 cm, and the stress of each section is detected to obtain the stress situation of the pipeline foundation, as shown in Figure 1 .

[0021]

[0022] S3, in one embodiment, the pipeline is subjected to non-contact weak magnetic detection, the weak magnetic signal of the pipeline is obtained, and the obtained pipeline magnetic signal is as shown in Figure 2 . According to the pipeline stress situation, the magnetic signal obtained by the weak magnetic detection is inversed to obtain the inversion model of the weak magnetic signal and the pipeline stress. As shown in formula (2).

[0023]

[0024] S4, in one embodiment, according to the inversion model of the weak magnetic signal and the pipeline stress, the non-contact weak magnetic detection equipment is carried by the unmanned aerial vehicle to detect the crossing pipeline, and the overall stress distribution of the crossing pipeline is obtained, as shown in Figure 3 .

[0025] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not deviate from the technical solution of the present application. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A method for obtaining the overall stress state of a product oil pipeline crossing section, characterized in that, Comprise the following steps: S1, data collection, collect basic information and field information of pipeline, including: pipe diameter, pipeline span, wall thickness, pipe material, yield strength. Complete a product pipeline crossing section stress overall state acquisition of the preliminary work; S2, ground pipeline stress acquisition, contact coercivity-stress detection is carried out on the ground pipeline (such as buried pipeline or crossing pipeline in and out of the soil section), and stress detection is carried out in n circumferential directions. The number of detection points n is related to the pipe diameter, and the calculation method is shown in formula (1). Each point is detected 3 times, and the average value of three times is taken as the detection result; the stress values of n detection points are averaged to obtain the stress value of the pipeline section. Repeat the operation, and detect the stress of each section every 10 cm for a pipeline of at least 2 m long to obtain the pipeline basic stress condition, ， In the formula: n is the number of detection points; [ ] is the integral symbol; d is the pipe diameter, mm; S3, non-contact weak magnetic detection is carried out on the pipeline to obtain the weak magnetic signal of the pipeline, and the magnetic signal obtained by the weak magnetic detection is inversed according to the pipeline stress condition to obtain the inversion model of the weak magnetic signal and the pipeline stress. As shown in formula (2): ， where: σ is the pipe stress value, MPa; is the pipe yield strength, MPa; G is the pipe magnetic signal; A is the pipe material coefficient; S4, according to the inversion model of the weak magnetic signal and the pipeline stress, the non-contact weak magnetic detection equipment is carried on the unmanned aerial vehicle to detect the crossing pipeline and obtain the overall stress distribution of the crossing pipeline.

2. The method for obtaining the stress general state of a product oil pipeline crossing section according to claim 1, characterized in that: In step S2, the ground pipeline stress acquisition, contact coercivity-stress detection is carried out on the ground pipeline (such as buried pipeline or crossing pipeline in and out of the soil section).

3. The method for obtaining the stress general state of a product oil pipeline crossing section according to claim 1, characterized in that: In step S3, the inversion model of the weak magnetic signal and the pipeline stress is established.

4. The method for obtaining the stress general state of a product oil pipeline crossing section according to claim 1, characterized in that: In step S4, according to the inversion model of the weak magnetic signal and the pipeline stress, the non-contact weak magnetic detection equipment is carried on the unmanned aerial vehicle to detect the crossing pipeline and obtain the overall stress distribution of the crossing pipeline.

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