A multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas

Abstract

The present invention discloses a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas, including a multi-field coupling monitoring subsystem placed on site and a monitoring and early warning subsystem placed on the server side. The multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a pipe surrounding soil temperature monitoring device. The pipeline strain monitoring device includes a strain sensor, a strain sensor protective cover, a monitoring section protection, a lead-out cable, and a cable protection tube. The strain sensor needs to be installed on the surface of the pipeline steel body, and the strain sensor is protected by a strain sensor protective cover. The outside of the protective cover is completely covered with a viscoelastic paste to play a waterproof and moisture-proof role, thereby extending the service life of the sensor. The monitoring and early warning system provided by the present invention is safe and reliable, can ensure the long-term and stable operation of the monitoring device, provide continuous and effective monitoring data, and timely issue early warning information based on the monitoring data to prevent pipeline accidents caused by frost heave and thaw settlement.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas pipeline and frozen soil monitoring, and in particular to a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas. Background Art

[0002] Frozen soil refers to soil or rock layers with a temperature below 0°C and containing ice. In my country, frozen soil is mainly distributed in the high-latitude areas of Northeast China and the high-altitude areas of Northwest China. Taking the Greater Khingan Range in Northeast China as an example, the average minimum temperature in winter is below -25°C, and the extreme low temperature is even below -50°C, which provides good conditions for the existence of frozen soil. When oil and gas pipelines pass through frozen soil areas, the surface cover conditions along the pipelines are destroyed due to the construction and operation of the pipelines. In particular, the pipelines that transport oil at positive temperatures as heat sources affect the hydrothermal state of the frozen soil along the pipelines, changing the physical and mechanical properties of the frozen soil, resulting in constant changes in the frozen soil environment, the southern boundary of seasonal frozen soil moving northward, and the degradation of permafrost has become a prominent problem along the pipelines. In this process, due to the influence of differential frost heave of frozen soil, the pipelines have different degrees of uplift and deformation, and local pipelines have even been lifted out of the ground by frost heave hills and warped; due to the influence of uneven thawing and settlement, the pipe base soil has seriously sunk and many exposed and suspended pipes have appeared. Affected by this, the pipeline will generate additional axial stress and bending stress under the action of external load, which can easily cause stress concentration in the pipeline. When the force exceeds the ultimate strength of the material, the pipeline will fail and be damaged.

[0003] In the prior art, some scholars have carried out some work on frozen soil temperature monitoring and pipeline deformation monitoring, but the existing monitoring is mainly based on single factor monitoring, such as frozen soil temperature monitoring (patent application number: 201922373591.8, patent application number: 201710755510.3, patent application number: 201210135934.7), pipeline deformation monitoring (patent application number: 201120429619.6, patent application number: 201110456598.1). The only comprehensive monitoring case that considers the temperature of the pipeline body and the surrounding temperature (patent application number: 201210137964.1) can only monitor the soil temperature and moisture content close to the pipeline, with a limited monitoring range, and can only monitor the displacement changes of the pipeline in the horizontal and vertical directions, and cannot reflect the axial deformation of the pipeline. In actual applications, it was also found that the degradation of the permafrost around the pipeline was increasingly obvious due to the thermal radiation of the pipeline, and the scope and depth of the affected permafrost continued to increase. Only focusing on the temperature changes of the permafrost on the pipeline surface and adjacent pipelines could not reflect the interaction between the pipeline and the permafrost, and could no longer meet the actual monitoring needs. In addition, due to the freezing and pulling effect of the permafrost, the borehole protection pipe was easily pulled out of the ground, resulting in the part of the temperature sensor chain exposed on the surface no longer being able to monitor the permafrost temperature, and the temperature sensors below the surface were misplaced, and the monitoring data was no longer the temperature value of the same layer of soil. At the same time, with the increase in the operating years, the monitoring device was damaged to varying degrees due to the repeated freezing and thawing of the permafrost, but it was difficult to achieve in-situ repair. Reinstallation not only increased the monitoring cost, but also caused differences between the new monitoring position and the original position, and the monitoring data was not directly comparable. More importantly, the axial stress of the pipeline is the most direct indicator for evaluating the safety of the pipeline. Although the existing method of calculating the mechanical state of the pipeline based on theoretical models by measuring the local displacement of the pipeline can reflect the stress characteristics of the pipeline to a certain extent, the assumptions based on this method may not be consistent with the actual situation, and there are errors in the measured displacement. Therefore, the calculation results cannot truly reflect the stress state of the pipeline and cannot be directly used to evaluate the safety of the pipeline. Summary of the invention

[0004] In order to solve the current situation that the monitoring factors in the existing monitoring technology are single, the interaction between pipes and soil cannot be effectively reflected, the monitoring device is easily damaged and difficult to repair in situ, and the monitoring indicators cannot be directly used to evaluate the safety of pipelines, the present invention provides a coupled monitoring and early warning system that can be used for long-term monitoring of the strain of the pipeline body and the temperature of the frozen soil around the pipeline in a field environment. By long-term monitoring of the microscopic deformation (strain) of the pipeline body and the soil temperature in a larger range around the pipe, attention is paid to the interaction between the frozen soil and the pipeline, and the influence of the frost heave and thaw settlement of the frozen soil on the mechanical properties of the pipeline and the temperature distribution characteristics of the soil around the pipe during positive temperature transportation of the pipeline are accurately grasped. A pipeline intrinsic safety monitoring and early warning system is established to realize automatic collection, remote transmission, automatic analysis, and forecast and early warning of monitoring data.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas, characterized in that it comprises a multi-field coupling monitoring subsystem placed at the monitoring site and a monitoring and early warning subsystem placed at the server end;

[0006] The multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a pipe surrounding soil temperature monitoring device; the pipeline strain monitoring device includes a strain sensor, a strain sensor protection cover, a monitoring section protection, a monitoring section lead-out cable, and a cable protection tube; the strain sensor is installed on the surface of the pipeline steel body using spot welding technology, the strain sensor is protected by a strain sensor protection cover, and the monitoring section is protected by an anti-corrosion tape and a cold wrap tape; the monitoring section lead-out cable is coiled above the pipeline in an S shape along the pipeline axis direction, and is protected by a cold wrap tape and a rubber sheet; the monitoring section lead-out cable is introduced into the surface integrated field monitoring station using the outer protective layer of the temperature sensor chain and the cable protection tube;

[0007] The pipe perimeter soil temperature monitoring device comprises a temperature sensor, a temperature sensor chain, a heat insulating cushion layer, an inner protective layer of the temperature sensor chain, an outer protective layer of the temperature sensor chain, an outer protective layer fixed expansion anchor, a temperature sensor chain lead-out cable and a cable protection tube; the temperature sensor chain is formed by a plurality of temperature sensors connected in parallel by a bus design, and each temperature sensor is provided with insulation protection; the internal bus of the temperature sensor chain is coiled in an S shape on the internal reinforcing ribs to increase the strength of the temperature sensor chain and prevent the frozen soil from frost heaving and thawing and sinking and pulling to damage the temperature sensor chain; a waterproof outer coat made of a heat conductive material is arranged on the outside of the temperature sensor chain to prevent water from entering the temperature sensor chain and causing a short circuit in the temperature sensor; outside the temperature sensor chain and between adjacent temperature sensors An insulating cushion layer is added to prevent air circulation in different layers from affecting the accuracy of frozen soil temperature measurement; the inner protective layer of the temperature sensor chain is fixed in the outer protective layer of the temperature sensor chain, and its bottom is sealed and the top is sealed with a waterproof joint to prevent the temperature sensor chain inserted therein from freezing and failing, and to facilitate the later repair of the temperature sensor chain; a fixed expansion anchor is provided at the bottom of the outer protective layer of the temperature sensor chain to fix the outer protective layer of the temperature sensor chain at a specified depth of frozen soil to prevent the outer protective layer of the temperature sensor chain from freezing and pulling out due to repeated frost heaving and thawing of the frozen soil; the lead-out cable of the temperature sensor chain is led out from the top of the inner protective layer of the temperature sensor chain using a waterproof joint and is introduced into the integrated surface field monitoring station using a cable protection tube.

[0008] The monitoring and early warning subsystem includes a data center, a system display platform and an early warning information release platform; after receiving the remotely sent data, the data center screens the data to determine that the data is accurate, performs background analysis and calculation, automatically calculates the pipeline stress at any position in the circumferential direction of the pipeline, draws contour maps and layered color maps of the frozen soil temperature distribution around the pipe within the monitoring range of the same period, and displays them on the system display platform; the data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. When the additional axial tensile and compressive stresses of the pipeline reach or exceed the set threshold, the system automatically releases early warning information to the early warning information release platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of text messages through the early warning information release platform.

[0009] In the above, the monitoring and early warning subsystem specifically includes the following steps:

[0010] Step 1: The data center enters the on-site pipeline strain monitoring data and the soil temperature monitoring data around the pipe into the pre-stored database;

[0011] Step 2: Filter the data in the pre-stored database; data screening is divided into two sub-steps: valid data screening and abnormal data screening; suppose that m data collection commands are issued each time data is collected, and n groups of data are successfully collected, then valid data screening and abnormal data screening are performed on the n groups of data in turn; valid data screening is to perform preliminary screening on the above n groups of data according to the sensor range, and remove invalid data that exceeds the sensor range, leaving n2 groups of data; abnormal data screening is to use the Grubbs test method to define the critical value Gp(n2) of the Grubbs test with a detection level of 5% for the remaining n2 groups of data, and calculate the mean of the remaining n2 groups of data in turn Standard Deviation and the Grubbs test statistic for each group Select the maximum Grubbs test statistic value G among the remaining n2 groups of data k (G k =max(G i )) for analysis, if G k >Gp(n2) indicates that the kth data is an abnormal value, and the kth data needs to be removed, and the above abnormal data screening process is repeated for the remaining n2=n2-1 groups of data until G k <Gp(n2), indicating that the remaining data are not abnormal values, the remaining data are retained and the average value of the remaining data is taken as the data after the measurement result value screening, and the data screening is ended at the same time;

[0012] Step 3: Perform pipeline strain / stress analysis and soil temperature field analysis around the pipe for the filtered data in step 2; Based on the plane section assumption and superposition principle in elastic theory, calculate the pipeline strain value at any position of the monitoring section according to the three sets of strain data on the monitoring section at the same time. The specific calculation steps are as follows:

[0013] The pipe strain consists of membrane strain, y-direction bending strain and z-direction bending strain. Suppose the membrane strain, maximum y-direction bending strain and maximum z-direction bending strain of the monitored section are ε m , According to the superposition principle, the strain at any point on the pipe cross section is:

[0014]

[0015] The monitored strain values ​​at the top and left and right sides of the pipeline are U(0,r o ), Its m , The relationship is as follows:

[0016] Formula 2:

[0017] Formula 3:

[0018] Formula 4: The film strain of the monitoring section represented by the monitoring strain and the maximum bending in the y and z directions are obtained from formula 2-4:

[0019] Formula 5:

[0020] Formula 6:

[0021] Formula 7: Combining the bending strains in the y and z directions, the maximum bending strain of the cross section can be obtained as follows:

[0022]

[0023] The angle at which the maximum bending strain occurs is, Formula 9:

[0024]

[0025] Accordingly, the maximum and minimum axial strains of the monitoring section are as follows: Formula 10:

[0026]

[0027] The axial strain at any point in the pipe cross section represented by the monitored strain is, Formula 11:

[0028]

[0029] Similarly, the maximum axial strain at each angle of the monitoring section can be obtained from the above formula: Formula 12:

[0030]

[0031] The average axial strain of the monitoring section is, Formula 13:

[0032]

[0033] The bending strain of the monitored section is, Formula 14:

[0034]

[0035] According to the pipeline stress-strain relationship curve, the maximum axial stress, average axial stress, and bending stress values ​​at each angle of the monitoring section are obtained by formula 12-formula 14. The circumferential force of the pipeline in each monitoring section is intuitively displayed on the system display platform, and the maximum axial stress, average axial stress, and bending stress values ​​of different monitoring sections are marked;

[0036] According to the temperature measurement results of each temperature sensor chain around the pipe, the soil temperature at different horizontal and vertical positions around the pipeline is calculated by interpolation method, and the contour map and layered color map of soil temperature distribution around the pipe are drawn. The distribution of frozen soil temperature at different positions on the soil temperature monitoring section around the pipe is intuitively displayed on the system display platform, thereby judging the distribution area of ​​frozen soil and the freeze-thaw state;

[0037] Step 4: Conduct pipe-soil interaction analysis; combine pipeline strain monitoring data with soil temperature data around the pipe to analyze the relationship between the mechanical state of the pipeline and the freeze-thaw state of the frozen soil;

[0038] Step 5: Conduct monitoring and early warning analysis; the data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. According to the ratio of the maximum value of the pipeline axial additional tensile and compressive stress to the allowable value of the axial additional tensile and compressive stress calculated in the third step, the corresponding early warning information is published to the early warning information publishing platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of SMS through the early warning information publishing platform. The specific steps are as follows:

[0039] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 30% of the allowable values ​​of the additional axial tensile and compressive stresses, the warning information release platform will release a blue warning message and automatically push the blue warning message to the designated user's mobile phone;

[0040] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 60% of the allowable values ​​of the additional axial tensile and compressive stress, the early warning information release platform will release a yellow early warning message and automatically push the yellow early warning message to the designated user's mobile phone;

[0041] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 90% of the allowable values ​​of the additional axial tensile and compressive stresses, the early warning information release platform will issue a red warning message and automatically push the red warning message to the designated user's mobile phone.

[0042] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: by carrying out coupled monitoring of pipeline body strain and frozen soil temperature around the pipeline, the present invention can not only directly and accurately grasp the stress state of the pipeline, but also monitor the frozen soil conditions around the pipeline during the same period, and provide basic data support for comprehensive analysis of the interaction between pipelines and frozen soil. At the same time, the monitoring and early warning subsystem issues early warning information based on the monitoring data, which helps to ensure the safety of pipeline operation. The present invention is equipped with extremely strong protection measures to avoid damage to sensors under repeated frost heave and thaw settlement; a fixing device for the outer protective layer of the temperature sensor chain is provided to prevent the outer protective layer from being exposed to the surface due to frozen soil frost heave; an inner protective layer of the temperature sensor chain is provided to repair the temperature sensor chain at the lowest cost when necessary. At the same time, the monitoring devices can be prepared in advance, reducing the workload of on-site construction and facilitating on-site installation. The monitoring and early warning system provided by the present invention is safe and reliable, can ensure the long-term and stable operation of the monitoring device, provide continuous and effective monitoring data, and timely issue early warning information based on the monitoring data to prevent pipeline accidents under the influence of frost heave and thaw settlement. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0044] Figure 1 It is a schematic diagram of a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas in an embodiment of the present invention.

[0045] Figure 2 This is one of the schematic diagrams of the multi-field coupling monitoring subsystem in the embodiment of the present invention.

[0046] Figure 3 Schematic diagram of strain sensor installation in an embodiment of the present invention.

[0047] Figure 4 Schematic diagram of the temperature sensing chain structure in an embodiment of the present invention.

[0048] Figure 5 This is the second schematic diagram of the multi-field coupling monitoring subsystem in the embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Embodiment 1

[0051] In order to solve the problem that the existing monitoring elements of pipelines in frozen soil areas are single or the monitoring elements are indirect elements, the embodiment of the present invention provides a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas. The technical solution is as follows:

[0052] like Figure 1 As shown, an embodiment of the present invention provides a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas, the system comprising a multi-field coupling monitoring subsystem placed at a monitoring site and a monitoring and early warning subsystem placed at a server end.

[0053] like Figure 2 , Figure 5As shown, the multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a pipe surrounding soil temperature monitoring device. The pipeline strain monitoring device includes a strain sensor (the strain sensor can be a vibrating string type or a fiber Bragg grating type. If it is a fiber Bragg grating strain sensor, a fiber Bragg grating temperature sensor must be added for temperature compensation), a strain sensor protection cover, a monitoring section protection, a monitoring section lead cable, and a cable protection tube; the strain sensor is installed on the steel surface of the pipeline using spot welding technology, the strain sensor is protected by a strain sensor protection cover, and the monitoring section is protected by an anti-corrosion tape and a cold wrap tape; the monitoring section lead cable is S-shaped and coiled above the pipeline along the pipeline axis, using a cold wrap tape and a rubber sheet. Protection; Use the outer protective layer of the temperature sensor chain and the cable protection tube to lead the monitoring section lead-out cable into the integrated surface field monitoring station; In order to effectively calculate the stress distribution in the circumferential direction of a monitoring section 201 of the pipeline 203, at least 3 sets of axial strain sensors are installed on a group of monitoring sections 201 (if it is a fiber Bragg grating strain sensor, a fiber Bragg grating temperature sensor must be added for temperature compensation). The axial strain sensor can be installed at any position on the circumference of the monitoring section 201. In order to facilitate on-site installation and subsequent analysis and calculation, it is preferred to install the axial strain sensor on the top and left and right sides of the pipeline. The entire monitoring section 201 is fixed and protected with anti-corrosion tape and cold wrapping tape to prevent the soil around the pipe from squeezing and shearing the sensor and cable. The lead-out cable 202 of the monitoring section 201 is S-shaped and coiled above the pipeline 203 along the pipeline axis, and is protected with cold wrapping tape and rubber sheet to prevent foreign objects in the trench backfill and soil above the pipeline from squeezing and damaging the cable. The cable leading out of the monitoring section 201 is introduced into the integrated surface field monitoring station using the temperature sensor chain outer protective layer 12 and the cable protection tube 204. The monitoring section 201 is the basic unit for pipeline strain monitoring. The number of sections is flexibly designed according to the actual monitoring pipe section length. It is recommended to arrange at least 3 groups of monitoring sections in the frozen soil section. Combined monitoring can obtain more abundant pipeline position information.

[0054] The soil temperature monitoring device around the pipe includes a temperature sensor (the temperature sensor can be a resistive type, a digital type, or a fiber grating type), a temperature sensing chain 13, a thermal insulation cushion, an inner protective layer 11 of the temperature sensing chain, an outer protective layer 12 of the temperature sensing chain, an outer protective layer fixed expansion anchor, a temperature sensing chain lead-out cable, and a cable protection tube 204.

[0055] The temperature sensing chain 13 is formed by connecting multiple temperature sensors in parallel using a bus design, and each temperature sensor uses insulation protection; the internal bus of the temperature sensing chain is coiled in an S shape on the internal reinforcing ribs to increase the strength of the temperature sensing chain to prevent the frozen soil from frost heaving and thawing and pulling to damage the temperature sensing chain. A waterproof coat made of heat-conducting material is set on the outside of the temperature sensing chain to prevent water from entering the temperature sensing chain and causing a short circuit in the temperature sensor; an insulation cushion layer is added outside the temperature sensing chain and between adjacent temperature sensors to prevent air circulation in different layers from affecting the accuracy of frozen soil temperature measurement; the protective layer 11 inside the temperature sensing chain is fixed In the outer protective layer 12 of the temperature sensor chain, its bottom is sealed and the top is sealed with a waterproof joint, which can prevent the temperature sensor chain inserted therein from being frozen and ineffective, and at the same time facilitate the later repair of the temperature sensor chain; a fixed expansion anchor is provided at the bottom of the outer protective layer 12 of the temperature sensor chain, which can fix the outer protective layer of the temperature sensor chain at a specified depth of the frozen soil, and prevent the outer protective layer of the temperature sensor chain from being frozen and pulled out due to repeated frost heaving and thawing of the frozen soil; the lead-out cable of the temperature sensor chain is led out from the top of the inner protective layer of the temperature sensor chain using a waterproof joint, and is introduced into the surface integrated field monitoring station using a cable protection tube 204.

[0056] The pipeline strain monitoring device and the soil temperature monitoring device around the pipe are both introduced into the temperature control box of the surface integrated field monitoring station 206 through the cable protection tube 204. The solar panel 205 placed outside the box and the battery inside the box are used to power the multi-field coupling monitoring subsystem, ensuring that the collection equipment is online for 24 hours, the data transmission equipment transmits data regularly, and the temperature inside the temperature control box is constant.

[0057] like Figure 3 As shown, the strain sensor 301 is installed on the steel body surface of the pipeline 302 using spot welding technology, so that the strain sensor 301 is tightly connected to the steel body of the pipeline 302, and the microscopic deformation of the pipeline 302 body is truly reflected; the strain sensor 301 is protected by a strain sensor protective cover to prevent the strain sensor 301 from being squeezed by foreign objects such as frozen soil around the pipe and causing failure; the strain sensor protective cover is fully covered with viscoelastic paste to prevent water vapor from entering and causing corrosion of the pipeline 302 body and rust of the strain sensor. The outer insulation layer 303 of the pipeline in the frozen soil area is restored to reduce the heat conduction of the pipeline body to the soil around the pipeline.

[0058] like Figure 4As shown, the temperature sensing chain is composed of multiple temperature sensors 402, which can be resistive, digital, distributed or quasi-distributed optical fiber temperature sensors. The temperature sensing chain has built-in reinforcement ribs, which can prevent the temperature sensing chain from being damaged by the frost heave and thaw sinking and pulling of the frozen soil, and facilitate implantation to the specified depth at the bottom of the borehole when the temperature sensing chain is replaced later. The spacing between the temperature sensors 402 and the length of the temperature sensing chain can be flexibly set according to monitoring needs. For seasonal frozen soil layers with obvious temperature changes and significant degradation areas, it is recommended that the temperature sensors 402 be densely distributed, and for permanent frozen soil areas, the sensors can be sparsely distributed. The temperature sensing chain is wrapped with a waterproof outer coat 401 made of thermal conductive material to prevent the temperature sensor from being short-circuited due to water ingress into the temperature sensing chain; an insulating cushion layer 403 is added between the temperature sensors to prevent air circulation at different levels from affecting the accuracy of frozen soil temperature measurement. The temperature sensing chain can be customized in advance according to the design, and the auxiliary materials can be installed indoors to save on-site installation time. The temperature sensing chain is set on the outer surface of the pipeline and in the frozen soil around the pipeline. When setting the temperature sensor chain on the outer surface of the pipeline, it is necessary to excavate and expose the pipe body, lay the temperature sensor chain around the pipe, and add protective measures to protect the temperature sensor chain; the temperature sensor chain is led out of the ground using an outer protective pipe 405 just above the pipeline, and the outer protective pipe is made upright, and the pipeline is backfilled, with the backfill soil basically level with the top of the protective pipe.

[0059] When setting up a temperature sensor chain around a pipeline, it is necessary to position it on a line perpendicular to the pipe axis, and use a drill to drill to the specified depth before implanting the outer protective tube 405 of the temperature sensor chain. The outer protective tube 405 of the temperature sensor chain is made of ABS material and consists of a straight-through, a flexible joint, an elbow, a blind cap, etc. The outer protective tube can be flexibly combined according to the drilling depth. The bottom of the outer protective tube 405 is blocked and equipped with an expansion anchor. After implantation to the specified depth, continue to apply force, and the bottom expansion anchor can automatically open and expand to grab the surrounding soil, so as to fix the bottom of the outer protective tube 405, which can effectively prevent the outer protective tube from freezing and pulling out due to repeated frost heaving and thawing of frozen soil.

[0060] After the outer protective tube 405 is fixed, the temperature sensor chain with the insulation layer 403 is inserted into the inner protective tube 404, the bottom of the inner protective tube 404 is blocked, and the inner protective tube 404 is fixed in the bottom clamping hole of the outer protective tube 405. The top of the inner protective tube 404 is blocked with a waterproof connector, and the cable at the end of the temperature sensor chain is led out by the waterproof connector.

[0061] The inner protective tube 404 can prevent freezing in the hole. If the sensor chain fails later, the surface can be partially excavated to expose the top of the inner protective tube 404. After the damaged sensor chain is pulled out, a temperature sensor chain of the same specification can be re-implanted to complete the sensor chain repair. The operation is simple and the on-site earthwork workload is small, avoiding time-consuming and wasteful re-drilling.

[0062] Each longitudinal temperature sensor chain lead-out cable is led to the integrated field monitoring station temperature control box through a shallow underground cable trough near the surface. The temperature sensor chain lead-out cable is worn in a cable protection tube with good elasticity, low temperature resistance and corrosion resistance, and the cable trough is filled with sand to minimize cable damage caused by strong surface frost heave and thaw settlement, extending the service life of the temperature sensor chain.

[0063] The present invention is equipped with extremely strong protection measures to prevent damage to the sensor under repeated frost heave and thaw settlement; a fixing device for the outer protection tube 405 of the temperature sensor chain is provided to prevent the outer protection tube 405 from being exposed to the surface due to frost heave of frozen soil; an inner protection layer 404 of the temperature sensor chain is provided to facilitate repairing the temperature sensor chain at the lowest cost when necessary.

[0064] The pipeline strain monitoring section and the soil temperature monitoring section around the pipe can be flexibly networked according to the monitoring environment and monitoring needs. For pipelines with a single heat source, considering the symmetry of thermal radiation, monitoring the soil temperature on one side of the pipeline can reflect the temperature around the pipeline. When there is a sufficient on-site investigation, it is recommended to place the temperature monitoring section in places with higher soil content such as adjacent water and catchment areas. For the case of two parallel pipes with two heat sources, consider setting up a temperature monitoring section in the middle area of ​​the two parallel pipes.

[0065] The on-site integrated field monitoring station uses anti-freeze pull technology to effectively prevent the base from being exposed to the surface due to frost heave.

[0066] The integrated field monitoring station is equipped with a temperature-controlled chassis, a solar power supply device outside the chassis, and a large-capacity battery, a collector, a transmission module and a lightning protection device inside the chassis, which can provide 24-hour online measurement for the collection and transmission equipment. When the temperature is lower than the set temperature limit, the insulated chassis can automatically heat up to avoid failure of the collection and transmission equipment in extremely cold conditions.

[0067] The monitoring and early warning system is deployed on a designated server (physical server or cloud server). The monitoring and early warning system includes a data center, a system display platform and an early warning information release platform.

[0068] The on-site monitoring data can be transmitted to the designated server through the data transmission module. To prevent interference with command signals, the host computer issues commands and the lower computer transmits data using encryption.

[0069] After the data center receives the remotely sent data, it screens the data and confirms that the data is accurate, then performs background analysis and calculation. It can automatically calculate the pipeline stress at any position in the circumferential direction of the pipeline, and intuitively display the circumferential force of the pipeline in each monitoring section on the system display platform, marking the maximum axial stress, average axial stress, and bending stress values ​​of different monitoring sections; based on the temperature measurement results of each temperature sensor chain around the pipe, the soil temperature at different horizontal and vertical positions around the pipeline is calculated using the interpolation method, and the contour map of the frozen soil temperature distribution around the pipe within the monitoring range during the same period and the layered color map are drawn for display on the system display platform.

[0070] The data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. When the pipeline axial additional tensile and compressive stress reaches or exceeds the set threshold, the system automatically publishes the early warning information to the early warning information release platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of text messages through the early warning information release platform.

[0071] Embodiment 2

[0072] Based on the first embodiment, Figure 1 A further embodiment is a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas, including a multi-field coupling monitoring subsystem placed on site and a monitoring and early warning subsystem placed on the server side. The multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a pipe surrounding soil temperature monitoring device. The pipeline strain monitoring device includes a strain sensor (the strain sensor can be a vibrating string type or a fiber grating type. If it is a fiber grating strain sensor, a fiber grating temperature sensor needs to be added for temperature compensation), a strain sensor protective cover, a monitoring section protection, a lead-out cable, and a cable protection tube. The strain sensor needs to be installed on the surface of the steel body of the pipeline, and the strain sensor is protected by a strain sensor protective cover. The outside of the protective cover is completely covered with a viscoelastic paste to play a waterproof and moisture-proof role and extend the service life of the sensor.

[0073] In order to effectively calculate the stress distribution in the circumferential direction of a monitoring section of the pipeline, at least three sets of strain sensors are installed on a group of monitoring sections (if the fiber grating strain sensor is used, a fiber grating temperature sensor must be added for temperature compensation), and the monitoring section is fixed and protected with anti-corrosion tape and cold wrap tape.

[0074] The cable leading out of the monitoring section 201 is laid in an S shape along the top of the pipeline axis and protected with cold wrap tape and rubber sheet to prevent foreign objects in the trench backfill and the soil above the pipeline from squeezing and damaging the cable; the temperature sensor chain outer protective layer 12 and the cable protection tube 204 are used to introduce it into the surface integrated field monitoring station.

[0075] The soil temperature monitoring device around the pipe includes a temperature sensor (the temperature sensor can be a resistance type, a digital type, or a fiber grating type), a temperature sensor chain 13, an inner protective layer 11 of the temperature sensor chain, an outer protective layer 12 of the temperature sensor chain, an outer protective layer fixed expansion anchor, a temperature sensor chain lead-out cable, and a cable protection tube 204. The temperature sensor chain 13 is composed of multiple temperature sensors, and the temperature sensor setting spacing and the setting length of the temperature sensor chain 13 can be flexibly set according to actual monitoring needs. The temperature sensor chain 13 is set on the outer surface of the pipeline and in the frozen soil around the pipeline. According to symmetry, a temperature sensor is set on the top, side wall, and bottom of the pipeline respectively, and the temperature sensor distribution is reasonably set from the top of the pipeline to the ground surface according to the buried depth of the pipeline; on the side of the pipeline where the heat effect is more obvious, multiple temperature sensor chains are set along the direction perpendicular to the pipeline axis, and the temperature sensor chain 13 is vertically distributed in the frozen soil layer. The length of the temperature sensor chain 13 and the setting density of the temperature sensor are set according to actual needs. The temperature sensing chain inner protective layer 11 is arranged outside the temperature sensing chain 13, and the temperature sensing chain and the inner protective layer are arranged in the temperature sensing chain outer protective layer 12. The temperature sensing chain outer protective layer 12 is permanently fixed in the frozen soil layer to locate and prevent the temperature sensing chain 13 from being damaged by the frozen soil. The temperature sensing chain 13 is connected to the cable protection pipe near the surface and introduced into the integrated field monitoring station on the surface.

[0076] The strain sensor lead-out cable and the temperature sensor chain lead-out cable are connected to the strain collector or temperature collector in the temperature control chassis of the integrated field monitoring station, and are connected to the designated server-side data center through the DTU data transmission module. The field monitoring data can be transmitted to the data center in real time, and instructions from the server-side data center can also be received and corresponding operations performed.

[0077] A monitoring and early warning subsystem is deployed on the server side, which includes a data center, a system display platform and an early warning information release platform. After receiving the remotely sent data, the data center screens the data to determine that the data is accurate, and then performs background analysis and calculation. It can automatically calculate the pipeline stress at any position in the circumferential direction of the pipeline, draw contour maps and layered color maps of the frozen soil temperature distribution around the pipe within the monitoring range of the same period, and display them on the system display platform. The data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. When the additional axial tensile and compressive stresses of the pipeline reach or exceed the set threshold, the system automatically releases the early warning information to the early warning information release platform, and the early warning information release platform automatically pushes the early warning information to the designated user's mobile phone in the form of text messages.

[0078] The specific steps are as follows:

[0079] Step 1: The data center enters the on-site pipeline strain monitoring data and the soil temperature monitoring data around the pipe into the pre-stored database;

[0080] Step 2: Filter the data in the pre-stored database. Data screening is divided into two sub-steps: valid data screening and abnormal data screening. If m data collection commands are issued each time data is collected, and n groups of data are successfully collected, valid data screening and abnormal data screening are performed on the n groups of data in turn. Valid data screening is to conduct a preliminary screening of the above n groups of data based on the sensor range, eliminate invalid data that exceeds the sensor range, and leave n2 groups of data. Abnormal data screening is to define the critical value Gp(n2) of the Grubbs test with a detection level of 5% for the remaining n2 groups of data according to the Grubbs test method, and calculate the mean of the remaining n2 groups of data in turn. Standard Deviation and the Grubbs test statistic for each group Select the maximum Grubbs test statistic value G among the remaining n2 groups of data k (G k =max(G i )) for analysis, if G k >Gp(n2) indicates that the kth data is an abnormal value, and the kth data needs to be removed, and the above abnormal data screening process is repeated for the remaining n2=n2-1 groups of data until G k <Gp(n2), indicating that the remaining data are not abnormal values, the remaining data are retained and the average value of the remaining data is taken as the data after the measurement result value is filtered, and the data filtering is ended at the same time.

[0081] Step 3: Perform pipeline strain / stress analysis and soil temperature field analysis around the pipe for the filtered data in step 2. Based on the plane section assumption and superposition principle in elastic theory, the pipeline strain value at any position of the monitoring section can be calculated based on the three sets of strain data on the monitoring section at the same time (three sets of strain data and one set of temperature data when using fiber Bragg grating strain monitoring sensors). The specific calculation process is as follows:

[0082] The pipe strain consists of membrane strain, y-direction bending strain and z-direction bending strain. Suppose the membrane strain, maximum y-direction bending strain and maximum z-direction bending strain of the monitored section are ε m , According to the superposition principle, the strain at any point on the pipe cross section is:

[0083]

[0084] For the preferred axial strain sensor installation method mentioned in Example 1, the monitored strain values ​​at the top of the pipeline and on the left and right sides are U(0, r o ), Its m , The relationship is as follows:

[0085] Formula 2:

[0086] Formula 3:

[0087] Formula 4: From the above formulas 2-4, the monitoring section film strain represented by the monitoring strain and the maximum bending in the y and z directions are obtained respectively:

[0088] Formula 5:

[0089] Formula 6:

[0090] Formula 7:

[0091] Combining the bending strains in the y and z directions, the maximum bending strain of the cross section can be obtained as follows:

[0092]

[0093] The angle at which the maximum bending strain occurs is, Formula 9:

[0094]

[0095] Accordingly, the maximum and minimum axial strains of the monitoring section are as follows: Formula 10:

[0096]

[0097] The axial strain at any point in the pipe cross section represented by the monitored strain is, Formula 11:

[0098]

[0099] Similarly, the maximum axial strain at each angle of the monitoring section can be obtained from the above formula: Formula 12:

[0100]

[0101] The average axial strain of the monitoring section is, Formula 13:

[0102]

[0103] The bending strain of the monitored section is, Formula 14:

[0104]

[0105] According to Formula 12-Formula 14 and the pipeline stress-strain relationship curve, the maximum axial stress, average axial stress and bending stress values ​​at each angle of the monitored section can be obtained.

[0106] According to the temperature measurement results of each temperature sensor chain around the pipe, the soil temperature at different horizontal and vertical positions around the pipeline is calculated by interpolation method, and the soil temperature contour map and layered color map around the pipe are drawn to intuitively show the distribution of frozen soil temperature at different positions on the soil temperature monitoring section around the pipe, thereby judging the frozen soil distribution area and melting range.

[0107] Step 4: Analyze the pipe-soil interaction. Combine the pipeline strain monitoring data with the soil temperature data around the pipe to analyze the relationship between the mechanical state of the pipeline and the freeze-thaw state of the frozen soil. Generally speaking, when the surface soil around the pipe melts, the bending stress and axial stress of the pipeline tend to increase. However, due to the differences in the melting range and melting depth of the frozen soil around the pipe at different locations, the stress state of the pipeline varies. It is necessary to comprehensively analyze the interaction between the two in combination with the specific soil temperature field distribution around the pipe and the stress state of the pipeline.

[0108] Step 5: Conduct monitoring and early warning analysis. The data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and takes the pipeline intrinsic safety monitoring and early warning as the core. According to the ratio of the maximum value of the pipeline axial additional tensile and compressive stress to the allowable value of the axial additional tensile and compressive stress obtained by the third step analysis and calculation, the corresponding early warning information is issued to the early warning information release platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of SMS through the early warning information release platform. The specific steps are as follows:

[0109] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 30% of the allowable values ​​of the additional axial tensile and compressive stresses, the warning information release platform will release a blue warning message and automatically push the blue warning message to the designated user's mobile phone;

[0110] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 60% of the allowable values ​​of the additional axial tensile and compressive stresses, the early warning information release platform will issue a yellow early warning message and automatically push the yellow early warning message to the designated user's mobile phone terminal;

[0111] When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 90% of the allowable values ​​of the additional axial tensile and compressive stresses, the early warning information release platform will issue a red warning message and automatically push the red warning message to the designated user's mobile phone.

[0112] In summary, the present invention can directly and accurately grasp the stress state of the pipeline and monitor the frozen soil conditions around the pipeline by carrying out coupled monitoring of the pipeline body strain and the temperature of the frozen soil around the pipeline, thereby providing basic data support for the comprehensive analysis of the interaction between the pipeline and the frozen soil. At the same time, the monitoring and early warning system issues early warning information based on the monitoring data, which helps to ensure the safety of pipeline operation.

[0113] The present invention is equipped with extremely strong protection measures to prevent damage to sensors under repeated frost heave and thaw settlement; a fixing device for the outer protective layer of the temperature sensor chain is provided to prevent the protective layer from being exposed to the surface due to the influence of frozen soil frost heave; an inner protective layer of the temperature sensor chain is provided to repair the temperature sensor chain at the lowest cost when necessary. At the same time, the monitoring devices can be prepared in advance to reduce the workload of on-site construction and facilitate on-site installation. The monitoring and early warning system provided by the present invention is safe and reliable, can ensure the long-term and stable operation of the monitoring device, provide continuous and effective monitoring data, and timely issue early warning information based on the monitoring data to prevent pipeline accidents under the influence of frost heave and thaw settlement.

[0114] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas, characterized in that: It includes a multi-field coupling monitoring subsystem placed at the monitoring site and a monitoring and early warning subsystem placed at the server end; The multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a pipe surrounding soil temperature monitoring device; the pipeline strain monitoring device includes a strain sensor, a strain sensor protection cover, a monitoring section protection, a monitoring section lead-out cable, and a cable protection tube; the strain sensor is installed on the surface of the pipeline steel body using spot welding technology, the strain sensor is protected by a strain sensor protection cover, and the monitoring section is protected by an anti-corrosion tape and a cold wrap tape; the monitoring section lead-out cable is coiled above the pipeline in an S shape along the pipeline axis direction, and is protected by a cold wrap tape and a rubber sheet; the monitoring section lead-out cable is introduced into the surface integrated field monitoring station using the outer protective layer of the temperature sensor chain and the cable protection tube; The pipe perimeter soil temperature monitoring device comprises a temperature sensor, a temperature sensor chain, a heat insulating cushion layer, an inner protective layer of the temperature sensor chain, an outer protective layer of the temperature sensor chain, an outer protective layer fixed expansion anchor, a temperature sensor chain lead-out cable and a cable protection tube; the temperature sensor chain is formed by a plurality of temperature sensors connected in parallel by a bus design, and each temperature sensor is provided with insulation protection; the internal bus of the temperature sensor chain is coiled in an S shape on the internal reinforcing ribs to increase the strength of the temperature sensor chain and prevent the frozen soil from frost heaving and thawing and sinking and pulling to damage the temperature sensor chain; a waterproof outer coat made of a heat conductive material is arranged on the outside of the temperature sensor chain to prevent water from entering the temperature sensor chain and causing a short circuit in the temperature sensor; outside the temperature sensor chain and between adjacent temperature sensors Add a thermal insulation cushion layer to prevent air circulation at different layers from affecting the accuracy of frozen soil temperature measurement; the inner protective layer of the temperature sensor chain is fixed in the outer protective layer of the temperature sensor chain, and its bottom is sealed and the top is sealed with a waterproof joint to prevent the temperature sensor chain inserted therein from freezing and failure, and to facilitate the later repair of the temperature sensor chain; a fixed expansion anchor is provided at the bottom of the outer protective layer of the temperature sensor chain to fix the outer protective layer of the temperature sensor chain at a specified depth of frozen soil to prevent the outer protective layer of the temperature sensor chain from freezing and pulling out due to repeated frost heaving and thawing of frozen soil; the lead-out cable of the temperature sensor chain is led out from the top of the inner protective layer of the temperature sensor chain using a waterproof joint and introduced into the integrated surface field monitoring station using a cable protection tube; The monitoring and early warning subsystem specifically includes the following steps: Step 1: The data center enters the on-site pipeline strain monitoring data and the soil temperature monitoring data around the pipe into the pre-stored database; Step 2: Filter the data in the pre-stored database; data filtering is divided into two sub-steps: valid data filtering and abnormal data filtering; Assume that m data collection commands are issued each time data is collected, and n sets of data are successfully collected. Then, valid data screening and abnormal data screening are performed on the n sets of data in turn. Valid data screening is to conduct preliminary screening of the above n groups of data according to the sensor range, remove invalid data that exceeds the sensor range, and the remaining n2 groups of data; abnormal data screening is to use the Grubbs test method to define the critical value Gp(n2) of the Grubbs test with a detection level of 5% for the remaining n2 groups of data, and calculate the mean of the remaining n2 groups of data in turn Standard Deviation and the Grubbs test statistic for each group Select the maximum Grubbs test statistic value G among the remaining n2 groups of data k (G k =max(G i )) for analysis, if G k >Gp(n2) indicates that the kth data is an abnormal value, and the kth data needs to be removed, and the above abnormal data screening process is repeated for the remaining n2=n2-1 groups of data until G k <Gp(n2), indicating that the remaining data are not abnormal values, the remaining data are retained and the average value of the remaining data is taken as the data after the measurement result value screening, and the data screening is ended at the same time; Step 3: Perform pipeline strain / stress analysis and soil temperature field analysis around the pipe for the filtered data in step 2; based on the plane section assumption and superposition principle in elastic theory, calculate the pipeline strain value at any position of the monitoring section according to the three sets of strain data on the monitoring section at the same time. The specific calculation steps are as follows: The pipeline strain is composed of film strain, y-direction bending strain and z-direction bending strain. Let the film strain of the monitoring section, the maximum y-direction bending strain and the maximum z-direction bending strain be ε m , According to the superposition principle, the strain at any point on the pipe cross section is: The monitored strain values ​​at the top and left and right sides of the pipeline are U(0,r o ), Its m , The relationship is as follows: Formula 2: Formula 3: Equation 4: The film strain of the monitoring section represented by the monitoring strain and the maximum bending in the y and z directions are obtained from formula 2-4: Formula 5: Formula 6: Formula 7: Combining the bending strains in the y and z directions, the maximum bending strain of the cross section can be obtained as follows: The angle at which the maximum bending strain occurs is, Formula 9: Accordingly, the maximum and minimum axial strains of the monitoring section are as follows: Formula 10: The axial strain at any point in the pipe cross section represented by the monitored strain is, Formula 11: Similarly, the maximum axial strain at each angle of the monitoring section can be obtained from the above formula: Formula 12: The average axial strain of the monitoring section is, Formula 13: The bending strain of the monitored section is, Formula 14: According to the pipeline stress-strain relationship curve, the maximum axial stress, average axial stress, and bending stress values ​​at each angle of the monitoring section are obtained by formula 12-formula 14. The circumferential force of the pipeline in each monitoring section is intuitively displayed on the system display platform, and the maximum axial stress, average axial stress, and bending stress values ​​of different monitoring sections are marked; According to the temperature measurement results of each temperature sensor chain around the pipe, the soil temperature at different horizontal and vertical positions around the pipeline is calculated by interpolation method, and the contour map and layered color map of soil temperature distribution around the pipe are drawn. The distribution of frozen soil temperature at different positions on the soil temperature monitoring section around the pipe is intuitively displayed on the system display platform, thereby judging the distribution area of ​​frozen soil and the freeze-thaw state; Step 4: Conduct pipe-soil interaction analysis; combine pipeline strain monitoring data with soil temperature data around the pipe to analyze the relationship between the mechanical state of the pipeline and the freeze-thaw state of the frozen soil; Step 5: Conduct monitoring and early warning analysis; the data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. According to the ratio of the maximum value of the pipeline axial additional tensile and compressive stress to the allowable value of the axial additional tensile and compressive stress calculated in the third step, the corresponding early warning information is published to the early warning information publishing platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of SMS through the early warning information publishing platform. The specific steps are as follows: When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 30% of the allowable values ​​of the additional axial tensile and compressive stresses, the warning information release platform will release a blue warning message and automatically push the blue warning message to the designated user's mobile phone; When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 60% of the allowable values ​​of the additional axial tensile and compressive stresses, the early warning information release platform will issue a yellow early warning message and automatically push the yellow early warning message to the designated user's mobile phone terminal; When the additional axial tensile and compressive stress values ​​of the pipeline reach or exceed 90% of the allowable values ​​of the additional axial tensile and compressive stresses, the early warning information release platform will issue a red warning message and automatically push the red warning message to the designated user's mobile phone.

2. The multi-field coupling monitoring and early warning system for buried oil and gas pipelines in frozen soil areas according to claim 1 is characterized in that: The monitoring and early warning subsystem includes a data center, a system display platform and an early warning information release platform; after receiving the remotely sent data, the data center screens the data to determine that the data is accurate, performs background analysis and calculation, automatically calculates the pipeline stress at any position in the circumferential direction of the pipeline, draws contour maps and layered color maps of the frozen soil temperature distribution around the pipe within the monitoring range of the same period, and displays them on the system display platform; the data center integrates the pipeline strain analysis results and the soil temperature distribution around the pipe, and conducts pipeline intrinsic safety monitoring and early warning analysis based on the pipeline stress analysis results. When the additional axial tensile and compressive stresses of the pipeline reach or exceed the set threshold, the system automatically releases early warning information to the early warning information release platform, and the early warning information is automatically pushed to the designated user's mobile phone in the form of text messages through the early warning information release platform.

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