Online Monitoring Device and Method for External Corrosion of Submarine Pipelines

Abstract

The present invention relates to the technical field of subsea pipeline corrosion detection, and specifically discloses an on-line monitoring device and method for external corrosion of subsea pipelines. The device includes a probe mechanism, and the probe mechanism includes a probe body and a permanent magnet cylinder. The probe mechanism includes a probe body and a permanent magnet cylinder. The permanent magnet cylinder includes a first cylinder section and a second cylinder section arranged along the axis direction of the probe body. The first cylinder section is wrapped outside the probe body. One end of the second cylinder section away from the first cylinder section forms an adsorption end face for adsorbing to the pipeline to be measured. A containing cavity for containing a coupling agent is jointly formed between the inner cavity of the second cylinder section and the probe body, and a conveying pipeline for conveying the coupling agent is connected to the containing cavity. The probe mechanism of the present invention has a simple structure, can be adsorbed and fixed to the pipeline to be measured for a long time, realizes long-term on-line detection of subsea pipelines, and at the same time can select a more suitable coupling agent according to needs to improve the accuracy of ultrasonic detection data.

Description

Technical Field

[0001] The present invention relates to the technical field of subsea pipeline corrosion detection, and particularly to an on-line monitoring device and method for external corrosion of subsea pipelines. Background Art

[0002] As one of the five major transportation modes, pipelines have the advantages of high safety, good continuity, and large transportation volume, and are widely used in the transportation of offshore oil and gas. However, since subsea pipelines are exposed to seawater, and the ocean is an extremely corrosive environment, various steel facilities are extremely prone to corrosion and damage in the marine environment. The corrosion of metal structures is more serious than that on land. Physical, chemical, and biological factors can all cause corrosion. Moreover, once corrosion damage occurs, repair is extremely difficult and the consequences are unthinkable.

[0003] At present, most of the long-distance pipelines in China have been in service for more than 20 years. The pipelines are frequently perforated due to corrosion damage, and the repair and renewal rate is relatively high. The corrosion and leakage of pipelines not only pollute the environment, but also cause irreparable economic losses to the country. Therefore, while the pipeline construction is developing rapidly, how to ensure the safe operation of pipelines has become an increasingly important issue.

[0004] An ultrasonic detection device can be used to detect the deformation and corrosion of pipelines and determine whether the pipe wall becomes thinner. However, the ultrasonic detection device has relatively strict requirements for the detection environment. The reason is that when there is air between the ultrasonic probe and the workpiece to be detected, the ultrasonic wave will be reflected and cannot enter the workpiece to be detected. In order to enable the ultrasonic wave to penetrate smoothly into the workpiece to be detected, a sound-transmitting coupling medium (i.e., coupling agent) needs to be applied between the ultrasonic probe and the detection surface of the workpiece to be detected to exclude the air here. Due to different condition factors such as the material of the workpiece to be detected, the surface roughness, and the detection method (such as upward detection or side detection), the applicable coupling agent material and viscosity are also different. Otherwise, it will affect the accuracy of the final ultrasonic detection data. Therefore, choosing a suitable coupling agent is crucial for the accuracy of ultrasonic detection data.

[0005] Since subsea pipelines are immersed in the seabed for a long time, only seawater can be used as the coupling agent, and it is difficult to select a suitable ultrasonic detection coupling agent according to different condition factors of subsea pipelines, resulting in low accuracy of the detected data and poor detection effect. In addition, each detection requires transporting the ultrasonic detection device to each detection point for detection, making it difficult to realize the on-line detection of subsea pipelines. Summary of the Invention

[0006] The object of the present invention is to provide an on-line monitoring device and method for external corrosion of submarine pipelines in view of the existing technical status. The probe mechanism of the present invention has a simple structure, can be adsorbed and fixed on the pipeline to be measured for a long time, realizes long-term on-line detection of submarine pipelines, and can select a more suitable coupling agent according to needs to improve the accuracy of ultrasonic detection data.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] On the one hand, the present invention provides an on-line monitoring device for external corrosion of submarine pipelines, including a probe mechanism. The probe mechanism includes a probe body and a permanent magnet cylinder. The permanent magnet cylinder includes a first cylinder section and a second cylinder section arranged along the axis direction of the probe body. The first cylinder section is wrapped outside the probe body. One end of the second cylinder section away from the first cylinder section forms an adsorption end face for adsorbing to the pipeline to be measured. A receiving cavity for accommodating a coupling agent is jointly formed between the inner cavity of the second cylinder section and the probe body, and a conveying pipeline for conveying the coupling agent is connected to the receiving cavity.

[0009] Preferably, the permanent magnet cylinder includes at least two splicing blocks, the splicing blocks are radially distributed, the cross-section of the splicing blocks is in a fan-shaped ring structure, and the side walls of adjacent splicing blocks adsorb to each other.

[0010] Preferably, the first cylinder section adsorbs to the outer wall of the probe body.

[0011] Preferably, there is a clearance fit between the first cylinder section and the probe body.

[0012] Preferably, a fixing collar assembly is further provided outside the permanent magnet cylinder. The fixing collar assembly includes a limiting ring arranged along the axis direction of the permanent magnet cylinder. At least two arc-shaped pressing blocks are provided between the limiting ring and the permanent magnet cylinder. The arc-shaped pressing blocks are radially distributed, and each arc-shaped pressing block is connected with an adjusting rod for driving the arc-shaped pressing block to move in the radial direction. One end of the adjusting rod away from the arc-shaped pressing block penetrates through the limiting ring and is connected with a locking member.

[0013] Preferably, the arc-shaped pressing blocks and the splicing blocks are arranged in a staggered manner, and the central angle corresponding to the arc-shaped pressing blocks is greater than or equal to the central angle corresponding to the splicing blocks.

[0014] Preferably, the coupling agent is any one or a combination of industrial butter, lubricating grease, industrial vaseline, machine oil, glycerin, chemical paste or water glass.

[0015] Preferably, the on-line monitoring device for external corrosion of submarine pipelines includes:

[0016] Multiple ultrasonic thickness gauges are used to collect and record the wall thickness data of the pipeline to be measured. The ultrasonic thickness gauge includes an instrument body and the above-mentioned probe mechanism;

[0017] A main control computer is used to process the wall thickness data of the pipeline to obtain the corrosion condition of the pipeline to be measured;

[0018] An underwater robot is used to transmit the wall thickness data of the pipeline to be measured collected by the ultrasonic thickness gauge to the main control computer.

[0019] On the other hand, the present invention also provides an on-line monitoring method for external corrosion of submarine pipelines, including the following steps:

[0020] Adsorb multiple probe mechanisms on each detection point of the pipeline to be measured respectively;

[0021] Regularly collect the wall thickness data of the pipeline to be measured through multiple ultrasonic thickness gauges;

[0022] The underwater robot transmits the wall thickness data of the pipeline to be measured collected by the ultrasonic thickness gauge to the main control computer;

[0023] The main control computer processes the wall thickness data of the pipeline to obtain the corrosion condition of the pipeline to be measured.

[0024] The beneficial effects of the present invention are as follows:

[0025] In the present invention, a permanent magnet cylinder is enclosed around the probe body. The magnetic adsorption effect of the permanent magnet cylinder can firmly fix the probe body on the pipeline to be measured for a long time. Therefore, the external corrosion condition of the submarine pipeline can be detected online for a long time. The fixing method of the probe mechanism is simple and can be applied to pipelines to be measured with different diameters. At the same time, a closed cavity for accommodating the coupling agent is formed between the probe body and the wall surface of the pipeline to be measured through the permanent magnet cylinder, isolating the coupling agent from the external environment, so that the coupling agent can be used in the submarine environment. Therefore, a more suitable coupling agent can be selected according to needs, improving the accuracy of ultrasonic detection data. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the probe mechanism of the present invention installed on the pipeline to be measured.

[0027] Figure 2 It is a schematic internal structure diagram of the probe mechanism of the present invention.

[0028] Figure 3 It is a schematic structural diagram of the probe mechanism of the present invention.

[0029] Figure 4 It is a schematic structural diagram of the probe mechanism of the present invention from another perspective.

[0030] Figure 5 It is an exploded view of the probe mechanism of the present invention.

[0031] Figure 6 This is a schematic structural diagram of the fixed collar assembly of the present invention.

[0032] Figure 7 This is a schematic structural diagram of the on-line monitoring device for external corrosion of submarine pipelines of the present invention.

[0033] Figure 8 This is another schematic structural diagram of the on-line monitoring device for external corrosion of submarine pipelines of the present invention. Detailed implementation manners

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0035] Embodiment 1

[0036] Please refer to Figures 1 to 2 As shown, the present invention provides an on-line monitoring device for external corrosion of submarine pipelines, including a probe mechanism 1. The probe mechanism 1 includes a probe body 11 and a permanent magnet cylinder 12. In this embodiment, the permanent magnet cylinder 12 can be an alloy permanent magnet material, such as neodymium iron boron permanent magnet material, samarium cobalt permanent magnet material, alnico permanent magnet material, etc., or can also be a ferrite permanent magnet material. The permanent magnet cylinder 12 includes a first cylinder section 121 and a second cylinder section 122 arranged along the axis direction of the probe body 11. The first cylinder section 121 is wrapped outside the probe body 11. One end of the second cylinder section 122 away from the first cylinder section 121 forms an adsorption end face 123 for adsorbing to the pipeline 5 to be measured. A containing cavity 124 for containing a coupling agent is jointly formed between the inner cavity of the second cylinder section 122 and the probe body 11. And a conveying pipeline 14 for conveying the coupling agent is connected to the containing cavity 124. In this embodiment, the conveying pipeline 14 penetrates through the probe body 11 and extends into the containing cavity 124. In another implementation manner, the conveying pipeline 14 can also enter the containing cavity 124 by penetrating through the permanent magnet cylinder 12.

[0037] Refer to Figure 1 、 Figure 2 and Figure 4 As shown, during use, the permanent magnet cylinder 12, the conveying pipeline 14 and the probe body 11 are assembled. By using the magnetic adsorption effect of the permanent magnet cylinder 12, the probe body 11 is adsorbed and fixed on the outer wall of the pipeline 5 to be measured through the adsorption end face 123. Subsequently, the coupling agent is conveyed and filled into the containing cavity 124 through the conveying pipeline 14, and then the detection operation can be carried out.

[0038] In the present invention, a permanent magnet cylinder 12 is enclosed around the probe body 11. By using the magnetic adsorption of the permanent magnet cylinder 12, the probe body 11 can be firmly fixed on the pipeline 5 to be measured for a long time. Thus, the external corrosion of the submarine pipeline can be detected online for a long time. The fixing method of the probe mechanism 1 is simple and can be applied to pipelines 5 to be measured with different diameters. At the same time, a closed accommodating cavity 124 for accommodating the coupling agent is formed between the probe body 11 and the wall surface of the pipeline 5 to be measured through the permanent magnet cylinder 12, isolating the coupling agent from the external environment, so that the coupling agent can be used in the submarine environment. Therefore, a more suitable coupling agent can be selected according to needs, improving the accuracy of ultrasonic detection data.

[0039] In a specific embodiment, when the diameter of the pipeline 5 to be measured is much larger than the diameter of the permanent magnet cylinder 12, the mounting surface of the permanent magnet cylinder 12 tends to be a plane relative to the adsorption end surface 123. After the permanent magnet cylinder 12 is adsorbed on the pipeline 5, there is no gap at the connection between the two. At this time, the permanent magnet cylinder 12 can be an integral structure.

[0040] In another preferred specific embodiment, the permanent magnet cylinder 12 is a split type. Specifically, as shown in Figure 2 and Figure 5 The permanent magnet cylinder 12 includes at least two splicing blocks 125. In this embodiment, the permanent magnet cylinder 12 includes six splicing blocks 125. The splicing blocks 125 are radially distributed. The cross-section of the splicing blocks 125 is in a sector ring structure, and the side walls of adjacent splicing blocks 125 adsorb to each other.

[0041] In this embodiment, the permanent magnet cylinder 12 is set as a split type structure. When the diameter of the pipeline 5 to be measured is small, the vertical staggering degree of the splicing blocks 125 can be adjusted to make the adsorption end surface 123 form a curved surface parallel to the mounting surface of the pipeline 5 to be measured. Thus, the gap between the permanent magnet cylinder 12 and the pipeline 5 to be measured can be reduced, so that the permanent magnet cylinder 12 with the same diameter can be applied to pipelines 5 to be measured with more diameters.

[0042] On the other hand, setting the permanent magnet cylinder 12 as a split type structure is more convenient for disassembly and is beneficial for cleaning and maintenance.

[0043] The first cylinder section 121 adsorbs to the outer wall of the probe body 11.

[0044] There is a clearance fit between the first cylinder section 121 and the probe body 11.

[0045] See Figures 3 to 5As shown in the figure, a fixing collar assembly 13 is further provided outside the permanent magnet cylinder 12. The fixing collar assembly 13 includes a limiting ring 131 arranged along the axis direction of the permanent magnet cylinder 12. At least two arc-shaped pressing blocks 132 are provided between the limiting ring 131 and the permanent magnet cylinder 12. The arc-shaped pressing blocks 132 are radially distributed, and each arc-shaped pressing block 132 is respectively connected with an adjusting rod 133 for driving the arc-shaped pressing block 132 to move in the radial direction. The end of the adjusting rod 133 away from the arc-shaped pressing block 132 penetrates through the limiting ring 131 and is connected with a locking member 134. In this embodiment, the locking member 134 is a hexagonal nut, and the adjusting rod 133 is screwed with the hexagonal nut. In this embodiment, the fixing collar assembly 13 includes three arc-shaped pressing blocks 132, and each arc-shaped pressing block 132 is evenly arranged in the radial direction.

[0046] During use, the arc-shaped pressing block 132 is driven by the adjusting rod 133 to move in the radial direction, pushing the splicing block 125, so that each splicing block 125 moves closer to the axis direction, and the splicing between each splicing block 125 is tighter, further improving the connection tightness and firmness between each splicing block 125.

[0047] See Figures 3 to 4 As shown in the figure, the arc-shaped pressing blocks 132 and the splicing blocks 125 are arranged alternately, so that when each arc-shaped pressing block 132 is pushed, it can act on two adjacent splicing blocks 125 at the same time, and the pushing and gathering effect is better. And the central angle degree corresponding to the arc-shaped pressing block 132 is greater than or equal to the central angle degree corresponding to the splicing block 125, so that the arc-shaped pressing block 132 has a larger pushing action surface and the pushing and gathering effect is better.

[0048] The coupling agent is any one or a combination of industrial butter, lubricating grease, industrial vaseline, machine oil, glycerin, chemical paste or water glass.

[0049] In addition, the coupling agent can also be a commercial product specially prepared according to the required sound transmission (acoustic impedance), wettability, viscosity, etc. of the coupling agent. For example, the coupling agent of Elec ultrasonic thickness gauge has good coupling performance, is environmentally friendly and easy to clean.

[0050] Embodiment 2

[0051] See Figure 1 、 Figures 7 to 8 As shown in the figure, this embodiment provides an on-line monitoring device for external corrosion of submarine pipelines, including:

[0052] Multiple ultrasonic thickness gauges are fixed on the side wall of the pipeline 5 to be measured on the seabed, and are used to collect and record the wall thickness data of the pipeline 5 to be measured. The ultrasonic thickness gauge includes an instrument main body 2 and the probe mechanism 1 in Embodiment 1; the outside of the instrument main body 2 is wrapped with a seawater pressure-bearing sleeve; during detection, the ultrasonic pulse emitted by the probe main body 11 passes through the coupling agent to reach the detection surface of the pipeline 5 to be measured, and then the pulse is reflected back to the probe main body 11, and the thickness of the measured material is determined by accurately measuring the time for the ultrasonic wave to propagate in the material;

[0053] The main control computer 3 is installed on an offshore platform or on land and is used to process the pipeline wall thickness data to obtain the corrosion condition of the pipeline 5 to be measured;

[0054] The underwater robot 4 is used to transmit the wall thickness data of the pipeline 5 to be measured collected by the ultrasonic thickness gauge to the main control computer 3. The underwater robot 4 is communicatively connected to the main control computer 3 and the ultrasonic thickness gauge respectively.

[0055] See Figure 7 As shown, in a specific embodiment, one underwater robot 4 can transmit the data of multiple ultrasonic thickness gauges. See Figure 8 As shown, in another specific embodiment, one underwater robot 4 corresponds to transmitting the data of one ultrasonic thickness gauge.

[0056] In the present invention, data is transmitted by the underwater robot 4, so that the data analysis part can be transferred to the shore for processing, which is beneficial to the long-term online real-time detection of submarine pipelines.

[0057] This embodiment also provides an online monitoring method for external corrosion of submarine pipelines using the above online detection device, including the following steps:

[0058] S1. Adsorb multiple probe mechanisms 1 on each detection point of the pipeline 5 to be measured respectively;

[0059] S2. Regularly collect the wall thickness data of the pipeline 5 to be measured through multiple ultrasonic thickness gauges;

[0060] S3. The underwater robot 4 transmits the wall thickness data of the pipeline 5 to be measured collected by the ultrasonic thickness gauge to the main control computer 3: The underwater robot 4 moves to the location of the ultrasonic thickness gauge on the seabed, receives the wall thickness data of the pipeline 5 to be measured, and then the underwater robot 4 returns to the shore and transmits the data to the main control computer 3;

[0061] S4. The main control computer 3 processes the pipeline wall thickness data to obtain the corrosion condition of the pipeline 5 to be measured.

[0062] In a specific embodiment, the master computer 3 stores the original wall thickness data corresponding to the pipeline 5 to be measured. By comparing the current wall thickness data of each detection point with the original wall thickness data, the severity of corrosion at the current detection point can be obtained. The thinner the wall thickness, the deeper the corrosion degree.

[0063] In another specific embodiment, the master computer 3 stores the historical wall thickness data of each pipeline 5 to be measured. By comparing the historical wall thickness data of the same detection point, the corrosion rate at this detection point can be obtained.

[0064] Of course, the above illustrations are only preferred embodiments of the present invention and do not limit the scope of use of the present invention. Therefore, all equivalent changes made on the principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An on-line monitoring device for external corrosion of a subsea pipeline, the pipeline being a circular pipeline, comprising a probe mechanism, characterized in that, The probe mechanism includes a probe body and a permanent magnet cylinder column. The permanent magnet cylinder column includes a first cylinder section and a second cylinder section arranged along the axis direction of the probe body. The first cylinder section is wrapped outside the probe body. One end of the second cylinder section away from the first cylinder section forms an adsorption end face for adsorbing to the pipeline to be measured. A closed accommodation cavity for accommodating a coupling agent is jointly formed between the inner wall of the second cylinder section, the probe body and the wall surface of the pipeline to be measured. And the accommodation cavity is connected with a conveying pipeline for conveying the coupling agent. The permanent magnet cylinder column includes at least six splicing blocks. The splicing blocks are circumferentially distributed around the outside of the probe body. The cross-section of the splicing block is in a fan-shaped ring structure. And the side walls of adjacent splicing blocks adsorb to each other. Adjust the vertical staggering degree of the splicing blocks so that the adsorption end face forms a curved surface parallel to the installation surface of the pipeline to be measured.

2. The on-line corrosion monitoring device for the external corrosion of submarine pipelines according to claim 1, characterized in that The first cylinder section adsorbs to the outer wall of the probe body.

3. The on-line corrosion monitoring device for the external corrosion of submarine pipelines according to claim 1, characterized in that There is a clearance fit between the first cylinder section and the probe body.

4. The on-line corrosion monitoring device for the external corrosion of submarine pipelines according to claim 1, characterized in that A fixed collar assembly is further provided outside the permanent magnet cylinder column. The fixed collar assembly includes a limiting ring sleeved outside the permanent magnet cylinder column. At least two arc-shaped pressing blocks are arranged between the limiting ring and the permanent magnet cylinder column. The arc-shaped pressing blocks are circumferentially distributed around the outside of the permanent magnet cylinder column. And each arc-shaped pressing block is respectively connected with an adjusting rod for driving the arc-shaped pressing block to move in the radial direction. The end of the adjusting rod away from the arc-shaped pressing block penetrates through the limiting ring and is connected with a locking member.

5. The on-line corrosion monitoring device for the external corrosion of submarine pipelines according to claim 4, characterized in that, The arc-shaped pressing blocks and the splicing blocks are arranged in a staggered manner. And the central angle corresponding to the arc-shaped pressing block is greater than or equal to the central angle corresponding to the splicing block.

6. The on-line corrosion monitoring device for the external corrosion of the subsea pipeline according to claim 1, wherein The coupling agent is any one or a combination of industrial butter, lubricating grease, industrial vaseline, machine oil, glycerol, chemical paste or water glass.

7. The on-line corrosion monitoring device for submarine pipelines according to any one of claims 1 to 6, characterized in that, Including: Multiple ultrasonic thickness gauges for collecting and recording the wall thickness data of the pipeline to be measured. The ultrasonic thickness gauge includes an instrument body and a probe mechanism; A main control computer for processing the wall thickness data of the pipeline to obtain the corrosion condition of the pipeline to be measured; An underwater robot for transmitting the wall thickness data of the pipeline to be measured collected by the ultrasonic thickness gauge to the main control computer.

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