Device and method for monitoring corrosion in pipeline

Abstract

The invention provides a pipeline internal corrosion monitoring device which comprises a monitoring pipe section, a monitoring test piece assembly is arranged in the monitoring pipe section, the monitoring test piece assembly is provided with a first monitoring surface and a second monitoring surface which are opposite to each other, and the first monitoring surface faces and is close to a part of the pipe inner wall of the monitoring pipe section and forms a closed space with the pipe inner wall; and the second monitoring surface faces the flowing medium in the monitoring pipe section. According to the invention, the actual corrosion state of the supervision inner wall can be obtained, and the accuracy of pipe inner wall corrosion evaluation is improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas gathering and transportation technology, and more specifically, to a pipeline corrosion monitoring device and method. Background Technology

[0002] Oil and gas field gathering and transmission pipelines, as well as long-distance pipelines, are frequently plagued by corrosion problems (e.g., electrochemical corrosion). Two types of corrosion form at the interface between the pipe's inner wall and the corrosive fluid medium: first, corrosion caused by contact between the pipe's inner wall and the corrosive fluid medium, which is usually a uniform corrosion pattern; second, localized corrosion occurring in a relatively closed environment between the pipe's inner wall and the fouling deposits, including crevice corrosion, oxygen concentration cell corrosion, and bacterial corrosion. Although the second type of corrosion is localized, it causes more severe damage to the pipeline.

[0003] Currently, the corrosion monitoring method using corrosive plates is commonly used in the oil and gas industry. This method involves suspending a test piece perpendicular to the direction of the fluid flow inside the pipeline. However, this method can only detect corrosion at the interface between the corrosive medium and the test piece, but it cannot detect localized corrosion within the relatively enclosed environment of the pipe wall. This leads to a significant discrepancy between the monitored corrosion and the actual corrosion conditions on the pipe wall, making it impossible to infer the corrosion state of the pipe wall from the monitoring test. Summary of the Invention

[0004] One object of the present invention is to provide a corrosion monitoring device and method for pipelines, which can obtain the actual corrosion state of the pipeline wall and improve the accuracy of corrosion assessment of the pipeline wall.

[0005] According to the present invention, a pipeline corrosion monitoring device includes a monitoring pipe section, wherein a monitoring test piece assembly is disposed therein. The monitoring test piece assembly has a first monitoring surface and a second monitoring surface facing away from each other. The first monitoring surface faces and is close to a portion of the inner wall of the monitoring pipe section and forms a closed space with the inner wall of the pipe. The second monitoring surface faces the flowing medium inside the monitoring pipe section.

[0006] In a preferred embodiment, the second monitoring surface is parallel to the axis of the monitoring pipe segment.

[0007] In a preferred embodiment, a plurality of the monitoring test piece assemblies are provided within the monitoring pipe section.

[0008] In a preferred embodiment, a plurality of grooves extending along the axial direction of the monitoring pipe section are provided along the inner wall of the monitoring pipe section, and each monitoring test piece assembly is disposed in each of the grooves and abuts against the side wall surface of the groove.

[0009] In a preferred embodiment, the monitoring strip assembly is formed by bonding two monitoring strips together and insulating them together.

[0010] In a preferred embodiment, the monitoring tube segment includes a first receiving portion, a second receiving portion, and a connector disposed between the first receiving portion and the second receiving portion and connecting the two. The groove is provided along the inner wall of the first receiving portion and the second receiving portion, and the end face of the groove along the length direction abuts against the end face of the connector.

[0011] In a preferred embodiment, both the first receiving portion and the second receiving portion are made of a transparent material.

[0012] In a preferred embodiment, the first receiving portion and the second receiving portion are provided with flanges at the ends away from the joint.

[0013] In a preferred embodiment, the pipeline corrosion monitoring device further includes shut-off valves disposed upstream and downstream of the monitored pipe section and a drain outlet disposed between the monitored pipe section and the downstream shut-off valve.

[0014] The present invention also provides a method for monitoring corrosion inside pipelines, utilizing a pipeline corrosion monitoring device according to any one of claims 1 to 9, characterized in that it comprises:

[0015] S1. After cleaning and weighing multiple test pieces, apply adhesive to one side of each test piece and bond two test pieces together as a group to form a test piece assembly.

[0016] S2. The monitoring test piece assembly is placed in the groove of the first and second accommodating parts, with the first monitoring surface facing and close to a portion of the inner wall of the monitoring pipe section and forming a closed space with the inner wall, and the second monitoring surface facing the flowing medium in the monitoring pipe section and in contact with the flowing medium.

[0017] S3. Connect the ends of the first receiving part and the second receiving part to the connector respectively to assemble the monitoring pipe section, and use the monitoring pipe section as a bypass pipe of the pipe under test;

[0018] S4. During the monitoring process, the monitoring pipe section and the tested pipe flow simultaneously. The flow pattern and flow state of the fluid inside the monitoring pipe section, as well as the changes in the corrosion morphology of the monitoring test piece assembly, are observed through the first and second accommodating parts.

[0019] S5. Close the upstream and downstream shut-off valves of the monitoring pipe section and open the drain port. After depressurization and drainage, disassemble the monitoring pipe section, take out the monitoring test piece assembly from the groove, and analyze the monitoring test piece assembly.

[0020] In a preferred embodiment, analyzing the monitoring test piece assembly in step S5 includes:

[0021] S51. Macroscopic observation, microscopic corrosion morphology observation, corrosion product analysis, and corrosion rate calculation are performed on the first and second monitoring surfaces of the monitoring test piece assembly, respectively, to obtain data on local corrosion in the closed environment and data on electrochemical corrosion at the interface of the flowing medium.

[0022] S52. Compare and analyze the corrosion data of the first monitoring surface and the second monitoring surface to obtain the differences in corrosion between the two environments of the inner wall of the pipe.

[0023] This invention monitors a pipe section by installing a monitoring strip assembly. The monitoring strip assembly has a first monitoring surface and a second monitoring surface facing away from each other. The first monitoring surface faces and is close to a portion of the inner wall of the pipe section, forming a closed space with the inner wall. The second monitoring surface faces the flowing medium inside the pipe section. This allows for simultaneous monitoring of localized corrosion caused by the relatively closed environment between the inner wall and the fouling, as well as corrosion caused by the contact between the inner wall and the corrosive fluid medium. Based on the monitoring results, the actual corrosion state of the inner wall can be determined, improving the accuracy of the assessment of inner wall corrosion.

[0024] The monitoring section has multiple monitoring sample components, which can significantly increase the amount of test data obtained in each monitoring, thereby saving the manpower and material resources required for the test.

[0025] The second monitoring surface of the monitoring strip assembly is parallel to the axis of the monitoring pipe section, that is, parallel to the flow direction of the flowing medium in the monitoring pipe section. This makes the contact between the second monitoring surface of the monitoring strip assembly and the flowing medium in the pipe similar to the contact between the inner wall of the pipe and the flowing medium in an actual pipeline. The second monitoring surface will not obstruct the flowing medium in the monitoring pipe section, and the flowing medium in the monitoring pipe section will not have an impact on the second monitoring surface, thereby improving the accuracy of the monitoring results.

[0026] This invention features multiple grooves extending along the axial direction of the monitoring pipe section on its inner wall. Each monitoring strip assembly is disposed within each groove and abuts against the side wall of the groove. This allows the first monitoring surface of the monitoring strip assembly and the groove to form a closed space. On the one hand, this facilitates localized corrosion caused by the relatively closed environment formed between the inner wall of the monitoring pipe and the dirt on the inner wall. On the other hand, the grooves effectively protect the monitoring strip assembly from damage caused by other substances mixed into the monitoring pipe section.

[0027] The present invention monitors a tube segment comprising a first receiving portion, a second receiving portion, and a connector disposed between the first receiving portion and the second receiving portion and connecting the two portions. Grooves are provided along the inner walls of the first receiving portion and the second receiving portion. The end faces of the grooves of the first receiving portion and the second receiving portion respectively abut against the two end faces of the connector. While connecting the ends of the first receiving portion and the second receiving portion, the connector can seal the opening end of the groove along the length direction, thereby restricting the axial movement of the monitoring test piece assembly. Attached Figure Description

[0028] Figure 1 A schematic diagram of the overall structure of the pipeline corrosion monitoring device according to the present invention is shown.

[0029] Figure 2 A schematic diagram of the monitoring pipe section according to the present invention is shown.

[0030] Figure 3 A schematic diagram of the cross-sectional structure of the monitoring pipe section according to the present invention at point 1-1 is shown.

[0031] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0032] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "upstream," "inner," "outer," "convex," "concave," "far away," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0034] In this invention, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, an integral part, or an abutment; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] like Figure 1 As shown, the pipeline corrosion monitoring device 100 of the present invention includes a monitoring pipe section a, shut-off valves b disposed upstream and downstream of the monitoring pipe section a, and a drain outlet c disposed between the monitoring pipe section a and the downstream shut-off valve b. The monitoring pipe section a is configured as a bypass pipe to the pipeline A under test. During the monitoring process, the monitoring pipe section a and the pipeline A under test flow simultaneously. When the flowing medium flows through the monitoring test piece assembly 2 in the monitoring pipe section a, corrosion-related information can be obtained through test piece analysis. Before disassembling the monitoring pipe section a, the shut-off valves b upstream and downstream of the monitoring pipe section a can be closed, and the drain outlet c can be opened for pressure relief and drainage. Subsequently, the monitoring pipe section a can be disassembled.

[0036] like Figure 2 and Figure 3 As shown, a monitoring strip assembly 2 is installed within monitoring pipe section a. Within monitoring pipe section a, the monitoring strip assembly 2 has a first monitoring surface and a second monitoring surface facing away from each other. The first monitoring surface faces and is close to a portion of the inner wall of monitoring pipe section a, forming a closed space with the inner wall to monitor localized corrosion caused by the relatively closed environment formed between the inner wall and the fouling. The second monitoring surface faces the flowing medium within monitoring pipe section a and is in full contact with the flowing medium to monitor corrosion caused by the contact between the inner wall and the corrosive fluid medium. Optionally, the monitoring strip assembly 2 is constructed as an elongated strip. It should be noted that the closed spaces mentioned in this invention are relatively closed spaces, not absolutely sealed spaces.

[0037] This invention monitors a section of pipe a by installing a monitoring strip assembly 2, which has a first monitoring surface and a second monitoring surface facing away from each other. The first monitoring surface faces and is close to a portion of the inner wall of the pipe section a, forming a closed space with the inner wall. The second monitoring surface faces the flowing medium inside the pipe section a. This invention enables the monitoring strip assembly 2 to simultaneously monitor localized corrosion caused by the relatively closed environment between the inner wall and the dirt on the inner wall, as well as corrosion caused by the contact between the inner wall and the corrosive fluid medium. Based on the monitoring results, the actual corrosion state of the inner wall can be known, thus improving the accuracy of the assessment of corrosion on the inner wall.

[0038] In one or more embodiments, the monitoring pipe section a has multiple monitoring test piece assemblies 2, which can significantly increase the amount of test data obtained in each monitoring, thereby saving manpower and material resources required for the test.

[0039] In one or more embodiments, the second monitoring surface is parallel to the axis of the monitoring pipe segment a.

[0040] Since the second monitoring surface of the monitoring strip assembly 2 is parallel to the axis of the monitoring pipe section a, that is, parallel to the flow direction of the flowing medium in the monitoring pipe section a, the contact mode between the second monitoring surface of the monitoring strip assembly 2 and the flowing medium in the pipe is similar to the contact mode between the inner wall of the pipe and the flowing medium in the actual pipeline. The second monitoring surface will not block the flowing medium in the monitoring pipe section a, and the flowing medium in the monitoring pipe section a will not have an impact on the second monitoring surface, thereby improving the accuracy of the monitoring results.

[0041] In one or more embodiments, a plurality of grooves 21 extending along the axial direction of the monitoring pipe segment a are provided along the inner wall of the monitoring pipe segment a. Each monitoring test piece assembly 2 is disposed in each groove 21 and abuts against the side wall surface of the groove 21, so that the first monitoring surface and the groove 21 form a closed space for monitoring localized corrosion caused by the relatively closed environment formed between the inner wall of the pipe and the dirt on the inner wall. The groove 21 is configured to form a convex groove radially outward from the monitoring pipe segment a, and its length should be set to accommodate the monitoring test piece assembly 2.

[0042] The present invention provides multiple grooves 21 extending along the axial direction of the monitoring pipe section a along the inner wall of the monitoring pipe section a, with each monitoring strip assembly 2 disposed in each groove 21 and abutting against the side wall surface of the groove 21. This allows the first monitoring surface of the monitoring strip assembly 2 and the groove 21 to form a closed space. On the one hand, this facilitates localized corrosion caused by the relatively closed environment formed between the inner wall of the monitoring pipe and the dirt on the inner wall; on the other hand, the grooves 21 can effectively protect the monitoring strip assembly 2 and prevent it from being damaged by other substances mixed in with the monitoring pipe section a.

[0043] In one or more embodiments, a plurality of grooves 21 are distributed in a circular pattern along the inner wall of the monitoring pipe segment a.

[0044] In one or more embodiments, the monitoring strip assembly 2 is formed by two monitoring strips being bonded together face to face and insulated. Alternatively, the monitoring strip assembly 2 is formed by bonding two monitoring strips together.

[0045] The present invention uses a test piece assembly 2, which is formed by two test pieces being attached face to face and insulated together. This allows both surfaces of the test piece assembly 2 to have corrosion monitoring functions. It can monitor local corrosion caused by the relatively closed environment formed between the inner wall of the pipe and the dirt on the inner wall, as well as corrosion caused by the contact between the inner wall of the pipe and the corrosive fluid medium. This improves the efficiency of corrosion monitoring and reduces the manpower and material resources required for the test.

[0046] In one or more embodiments, the monitoring tube segment a includes a first receiving portion 11, a second receiving portion 12, and a connector 4 disposed between the end of the first receiving portion 11 and the end of the second receiving portion 12, connecting the ends of the two portions. Optionally, the first receiving portion 11 and the second receiving portion 12 have the same structure, both configured as cylindrical sections with openings at both ends and having the same axis. Multiple grooves 21 extending along the axis of the first receiving portion 11 and the second receiving portion 12 are provided along their inner walls. Multiple monitoring test piece assemblies 2 are located within corresponding grooves 21 of the first receiving portion 11 and the second receiving portion 12, and the ends of the monitoring test piece assemblies 2 abut against the two end faces of the connector 4.

[0047] This invention monitors a pipe section a comprising a first receiving portion 11, a second receiving portion 12, and a connector 4 disposed between and connecting the first receiving portion 11 and the second receiving portion 12. Grooves 21 are provided along the inner walls of the first receiving portion 11 and the second receiving portion 12. The end faces of the grooves 21 of each of the first and second receiving portions 11 abut against the two end faces of the connector 4 along the length direction. While connecting the ends of the first and second receiving portions 11 and 12, the connector 4 can seal the open ends of the grooves 21 along the length direction, thereby restricting the axial movement of the monitoring test piece assembly 2. Optionally, the first and second receiving portions 11 and the connector 4 are connected by threads.

[0048] In one or more embodiments, both the first receiving portion 11 and the second receiving portion 12 are made of a transparent material, such as plexiglass.

[0049] The present invention makes both the first receiving part 11 and the second receiving part 12 transparent, so that the flow state of the internal flowing medium and the corrosion process of the test piece assembly 2 can be observed through the first receiving part 11 and the second receiving part 12.

[0050] In one or more embodiments, the monitoring pipe section a of the present invention further includes a flange 1, which is disposed at the end of the first receiving part 11 and the second receiving part 12 away from the joint 4, and the flange can be flexibly installed and removed between the monitoring pipes.

[0051] Based on the aforementioned pipeline corrosion monitoring device 100, the present invention also provides a pipeline corrosion monitoring method for monitoring localized corrosion caused by a relatively closed environment formed between the inner wall of the pipe and the inner wall fouling, and for monitoring corrosion caused by contact between the inner wall of the pipe and a corrosive fluid medium, including:

[0052] S1. After cleaning and weighing multiple test pieces, apply an adhesive (e.g., Vaseline) to one side of each test piece and bond two test pieces together as a group to form a test piece assembly 2.

[0053] S2. The monitoring test piece assembly 2 is placed in the groove 21 of the first receiving part 11 and the second receiving part 12. The first monitoring surface faces and is close to the inner wall of the monitoring pipe section a and forms a closed space with the inner wall to monitor the local corrosion caused by the relatively closed environment formed between the inner wall of the pipe and the dirt on the inner wall. The second monitoring surface faces the flowing medium in the monitoring pipe section a and is in contact with the flowing medium.

[0054] S3. Connect the end of the first receiving part 11 and the end of the second receiving part 12 to the connector 4 to assemble a monitoring pipe section a, and use the monitoring pipe section a as a bypass pipe of the pipe A under test.

[0055] S4. During the monitoring process, the monitoring pipe section a and the tested pipe A flow simultaneously. The flow pattern, flow state and corrosion morphology of the flow medium inside the monitoring pipe section a are observed through the transparent first containment part 11 and second containment part 12.

[0056] S5. Close the upstream and downstream shut-off valves b of monitoring pipe section a and open the drain outlet c. After depressurization and drainage, disassemble monitoring pipe section a and remove the monitoring test piece assembly 2 in the groove 21. Analyze the monitoring test piece assembly 2.

[0057] In one or more embodiments, step S5 includes: S51, performing macroscopic observation on the first monitoring surface and the second monitoring surface of the monitoring test piece assembly 2, observing the microscopic corrosion morphology using an electron microscope (SEM), analyzing corrosion products using XRD, and calculating the corrosion rate using the weight loss method, so as to obtain data on local corrosion in the closed environment and data on corrosion at the interface of the flowing medium, respectively; S52, comparing and analyzing the corrosion data of the first monitoring surface and the second monitoring surface to obtain the corrosion differences between the two environments of the inner wall of the pipe.

[0058] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A pipeline internal corrosion monitoring device, comprising a monitoring pipe section, a monitoring coupon assembly is arranged in the monitoring pipe section, the monitoring coupon assembly has a first monitoring surface and a second monitoring surface which are opposite to each other, the first monitoring surface faces and is close to a part of the inner wall of the monitoring pipe section and forms a closed space with the inner wall, and the second monitoring surface faces a flowing medium in the monitoring pipe section.

2. The pipe internal corrosion monitoring device of claim 1, wherein, The second monitoring surface is parallel to the axis of the monitoring pipe section.

3. The pipe internal corrosion monitoring device of claim 1, wherein, A plurality of monitoring coupon assemblies are arranged in the monitoring pipe section.

4. The pipe internal corrosion monitoring device of claim 3, wherein, A plurality of grooves extending along the axis of the monitoring pipe section are arranged along the inner wall of the monitoring pipe section, and each monitoring coupon assembly is arranged in each groove and abuts against the side wall of the groove.

5. The pipe internal corrosion monitoring apparatus of claim 1, wherein, The monitoring coupon assembly is formed by two monitoring coupons which are adhered to each other and insulatedly connected.

6. The pipe internal corrosion monitoring device of claim 4, wherein, The monitoring pipe section comprises a first accommodating part, a second accommodating part, and a joint arranged between the first accommodating part and the second accommodating part and connecting the two parts, the grooves are arranged along the inner walls of the first accommodating part and the second accommodating part, and the end faces of the grooves in the length direction abut against the end faces of the joint.

7. The pipe internal corrosion monitoring device of claim 6, wherein, The first accommodating part and the second accommodating part are both made of transparent material.

8. The pipe internal corrosion monitoring device of claim 6, wherein, Flanges are arranged at the end parts of the first accommodating part and the second accommodating part away from the joint.

9. The pipe internal corrosion monitoring apparatus of claim 1, wherein, Further comprising a shut-off valve arranged upstream and downstream of the monitoring pipe section and a blowdown port arranged between the monitoring pipe section and the downstream shut-off valve.

10. A method of monitoring internal corrosion of a pipeline using the internal corrosion monitoring device according to any one of claims 1 to 9, characterized by, Comprising: S1, cleaning and weighing a plurality of monitoring coupons, coating adhesive on one side of each coupon and adhering two coupons together to form a monitoring coupon assembly; S2, arranging the monitoring coupon assembly in the grooves of the first accommodating part and the second accommodating part, the first monitoring surface faces and is close to a part of the inner wall of the monitoring pipe section and forms a closed space with the inner wall, and the second monitoring surface faces and contacts the flowing medium in the monitoring pipe section; S3, connecting the end parts of the first accommodating part and the second accommodating part to the joint to assemble the monitoring pipe section, and arranging the monitoring pipe section as a bypass pipeline of the measured pipeline; S4, during the monitoring process, the monitoring pipe section and the measured pipeline flow at the same time, and the flow pattern, flow state of the flowing medium in the monitoring pipe section and the corrosion morphology change of the monitoring coupon assembly are observed through the first accommodating part and the second accommodating part. S5, closing the shut-off valves upstream and downstream of the monitoring pipe section, opening the blowdown port, disassembling the monitoring pipe section after pressure relief and blowdown, taking out the monitoring coupon assembly from the grooves, and analyzing the monitoring coupon assembly.

11. The method for monitoring corrosion inside a pipeline according to claim 10, characterized in that, The analysis of the monitoring coupon assembly in step S5 comprises: S51, performing macroscopic observation, microscopic corrosion morphology observation, analyzing corrosion products, and calculating corrosion rate on the first monitoring surface and the second monitoring surface of the monitoring coupon assembly respectively to obtain data of local corrosion in a closed environment and data of uniform corrosion at the interface of a flowing medium respectively; S52, comparing and analyzing the corrosion data of the first monitoring surface and the second monitoring surface to obtain the corrosion difference of the two environments of the inner wall of the pipeline.

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