CN111623733A - Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area - Google Patents
Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area Download PDFInfo
- Publication number
- CN111623733A CN111623733A CN202010613181.0A CN202010613181A CN111623733A CN 111623733 A CN111623733 A CN 111623733A CN 202010613181 A CN202010613181 A CN 202010613181A CN 111623733 A CN111623733 A CN 111623733A
- Authority
- CN
- China
- Prior art keywords
- pipeline
- monitoring
- strain
- data
- early warning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/04—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring the deformation in a solid, e.g. by vibrating string
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/18—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge using photoelastic elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/14—Supports; Fastening devices; Arrangements for mounting thermometers in particular locations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K3/00—Thermometers giving results other than momentary value of temperature
- G01K3/08—Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values
- G01K3/14—Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values in respect of space
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K2219/00—Thermometers with dedicated analog to digital converters
Abstract
The invention discloses a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil area. The multi-field coupling monitoring subsystem comprises a pipeline strain monitoring device and a soil temperature monitoring device around the pipeline. The pipeline strain monitoring device comprises a strain sensor, a strain sensor protective cover, a monitoring section protection, a leading-out cable and a cable protection pipe. The strain sensor needs to be installed on the surface of a pipeline steel body, the strain sensor is protected by a strain sensor protective cover, the protective cover is completely covered by viscoelastic paste, the waterproof and moistureproof effects are achieved, and the service life of the sensor is prolonged. The monitoring and early warning system provided by the invention is safe and reliable, can ensure long-term and stable operation of a monitoring device, provides continuous and effective monitoring data, and timely issues early warning information based on the monitoring data to prevent pipeline accidents caused by frost heaving and thaw collapse.
Description
Technical Field
The invention relates to the technical field of oil and gas pipelines and frozen soil monitoring, in particular to a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil area.
Background
The frozen soil is a soil layer or rock stratum with the temperature lower than 0 ℃ and containing ice, and is mainly distributed in northeast high-latitude areas and northwest high-altitude areas in China. Taking the northeast great Xingan mountain area as an example, the lowest temperature in winter is averagely below-25 ℃, and the extremely low temperature is even lower than-50 ℃, thereby providing good conditions for the occurrence of frozen soil. When an oil and gas pipeline passes through a frozen soil area, the ground surface coverage conditions along the pipeline are damaged under the influence of pipeline construction and operation, particularly, the pipeline for normal-temperature petroleum conveying is used as a heat source to influence the hydrothermal state of the frozen soil along the pipeline, the physical and mechanical properties of the frozen soil are changed, the frozen soil environment is continuously changed, the seasonal frozen soil moves to the south and the north, and the degradation of the frozen soil for many years becomes a prominent problem along the pipeline. In the process, the pipelines have different degrees of uplift deformation due to the influence of the difference frost heaving of the frozen soil, and the local pipelines are even lifted out of the ground by frost heaving to be in a warping shape; due to the influence of uneven melt-sinking, the pipe foundation soil is seriously sunk and a plurality of exposed pipes and hanging pipes appear. Under the influence, the pipeline generates axial additional stress and bending stress under the action of external load, the stress concentration of the pipeline is easily caused, and the pipeline is failed and damaged when the stress exceeds the ultimate strength of the material.
In the prior art, some work is carried out by scholars around frozen soil temperature monitoring and pipeline deformation monitoring, but the existing monitoring mainly adopts single factor monitoring, for example, frozen soil temperature monitoring (patent application number: 201922373591.8, patent application number: 201710755510.3, patent application number: 201210135934.7) and pipeline deformation monitoring (patent application number: 201120429619.6, patent application number: 201110456598.1) are carried out, only a comprehensive monitoring case (patent application number: 201210137964.1) considering the temperature of a pipeline body and the temperature around the pipeline can only monitor the temperature and the water content of soil at the position close to the pipeline, the monitoring range is limited, and only displacement changes of the pipeline in the horizontal direction and the vertical direction can be monitored, and axial deformation of the pipeline cannot be reflected. In practical application, the degradation of frozen soil around a pipeline is increasingly obvious under the influence of heat radiation of the pipeline, the range and the depth of the influenced frozen soil are continuously increased, the interaction between the pipeline and the frozen soil cannot be reflected only by focusing on the temperature change of the frozen soil on the surface of the pipeline and the adjacent pipeline, and the actual monitoring requirement cannot be met. In addition, due to the influence of frozen soil freezing and pulling, the drilling protection tube is easy to pull out of the ground, so that the temperature sensing chain exposed out of the ground can not monitor the temperature of the frozen soil any more, and the temperature sensor below the ground is staggered, so that the monitoring data are not the temperature value of the soil in the same layer any more. Meanwhile, along with the increase of the operating life, the monitoring device is damaged in different degrees due to the repeated frost heaving and thaw settlement of the frozen soil, in-situ repair is difficult to realize, the reinstallation increases the monitoring cost, the new monitoring position is different from the original position, and the monitoring data does not have direct comparability. More importantly, the axial stress of the pipeline is the most direct index for evaluating the safety of the pipeline. Although the existing method for calculating the mechanical state of the pipeline by measuring the local displacement of the pipeline and based on a theoretical model can reflect the stress characteristics of the pipeline to a certain extent, the assumed condition based on the method is not necessarily consistent with the actual condition, and the measured displacement has errors, so that the calculation result cannot truly reflect the stress state of the pipeline and cannot be directly used for evaluating the safety of the pipeline.
Disclosure of Invention
In order to solve the problems that monitoring factors are single, pipe soil interaction cannot be effectively reflected, a monitoring device is easy to damage and difficult to repair in situ and monitoring indexes cannot be directly used for evaluating whether the pipeline is safe or not in the prior art, the invention provides a coupling monitoring and early warning system which can be used for monitoring pipeline body strain and pipeline surrounding frozen soil temperature in a field environment for a long time.
In order to solve the technical problems, the invention provides the following technical scheme: a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil area is characterized by comprising a multi-field coupling monitoring subsystem arranged on a monitoring field and a monitoring and early warning subsystem arranged at a server end;
the multi-field coupling monitoring subsystem comprises a pipeline strain monitoring device and a soil temperature monitoring device around the pipeline; the pipeline strain monitoring device comprises a strain sensor, a strain sensor protective cover, a monitoring section protection, a monitoring section leading-out cable and a cable protection pipe; the strain sensor is installed on the surface of the pipeline steel body by using a spot welding technology, a strain sensor protective cover is used for protecting the strain sensor, and an anti-corrosion belt and a cold winding belt are used for protecting the monitoring section; the monitoring section lead-out cable is coiled above the pipeline in an S shape along the axis direction of the pipeline and is protected by a cold winding belt and a rubber plate; leading the cable led out of the monitoring section into an integrated field monitoring station on the earth surface by using an outer protection layer of the temperature sensing chain and a cable protection pipe;
the soil temperature monitoring device around the pipe comprises a temperature sensor, a temperature sensing chain, a heat insulation cushion layer, a temperature sensing chain inner protection layer, a temperature sensing chain outer protection layer, an outer protection layer fixing expansion anchor, a temperature sensing chain leading-out cable and a cable protection pipe; the temperature sensing chain is formed by connecting a plurality of temperature sensors in parallel by adopting a bus design, and each temperature sensor is insulated and protected; the internal bus of the temperature sensing chain is coiled on the internal reinforcing rib in an S shape, the strength of the temperature sensing chain is increased, frozen soil is prevented from being frozen and expanded, the temperature sensing chain is prevented from being damaged by thawing, sinking and dragging, and a waterproof coat made of a heat conduction material is arranged outside the temperature sensing chain, so that the temperature sensor is prevented from being short-circuited due to water entering the temperature sensing chain; a heat insulation cushion layer is added between the outer part of the temperature sensing chain and the adjacent temperature sensor, so that the influence of air circulation at different layers on the measurement accuracy of the frozen soil temperature is prevented; the inner protection layer of the temperature sensing chain is fixed in the outer protection layer of the temperature sensing chain, the bottom of the inner protection layer is plugged, the top of the inner protection layer is plugged by a waterproof joint, and the inner protection layer is used for preventing the temperature sensing chain penetrating into the inner protection layer from being failed by freezing and facilitating the later-stage repair of the temperature sensing chain; the bottom of the outer protection layer of the temperature sensing chain is provided with a fixed expansion anchor which is used for fixing the outer protection layer of the temperature sensing chain at a specified depth of frozen soil and preventing the outer protection layer of the temperature sensing chain from being frozen and pulled under the repeated freezing swelling and thawing sinking action of the frozen soil; the temperature sensing chain lead-out cable is led out from the top of the inner protection layer of the temperature sensing chain by using a waterproof connector and is led into the earth surface integrated field monitoring station by using a cable protection pipe.
The monitoring and early warning subsystem comprises a data center, a system display platform and an early warning information release platform; after the data center receives the remote sending data and the data are screened and determined to be accurate and correct, background analysis and calculation are carried out, the pipeline stress at any position in the circumferential direction of the pipeline is automatically calculated, a contour map and a layered color map of the temperature distribution of the surrounding frozen soil in the synchronous monitoring range are drawn and displayed on a system display platform; the data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, automatically issues early warning information to an early warning information issuing platform when the axial additional tensile and compressive stress of the pipeline reaches or exceeds a set threshold value, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message form through the early warning information issuing platform.
In the foregoing, the monitoring and early warning subsystem specifically includes the following steps:
the first step is as follows: the data center records the field pipeline strain monitoring data and the soil temperature monitoring data around the pipeline into a pre-stored database;
the second step is that:screening data in a pre-stored database; the data screening is divided into two sub-steps of effective data screening and abnormal data screening; issuing data acquisition commands for m times when data are acquired each time, and acquiring n groups of data successfully, then performing effective data screening and abnormal data screening on the n groups of data in sequence; the effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data; the abnormal data is screened for the remaining n according to the Grabbs test method2The data acquisition detection level was 5% defining the critical value Gp (n) of the Grabbs test2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And the Grabbs test statistic for each group number
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is an abnormal value, the k data needs to be removed, and the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) If the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the data after the screening of the current measurement result value, and the data screening is ended;
the third step: performing pipeline strain/stress analysis and soil temperature field analysis around the pipeline according to the screened data in the second step; based on the assumption and superposition principle of a flat section in the elasticity theory, 3 groups of strain data on the monitoring section at the same time are obtained (the strain value of the pipeline at any position of the monitoring section is calculated, and the specific calculation steps are as follows:
the pipeline strain is formed by film strain, y-direction bending strain andz-direction bending strain. The strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
the monitoring strain values of the top and the left and the right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
the monitored cross-sectional film strain and the maximum bending in the y-direction and z-direction, respectively, represented by the monitored strain are obtained from equations 2-4:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
obtaining maximum axial stress, average axial stress and bending stress values of each angle of the monitoring section according to a pipeline stress-strain relation curve by a formula 12-a formula 14, visually displaying the stress of the pipeline in the circumferential direction of each monitoring section on a system display platform, and labeling the maximum axial stress, the average axial stress and the bending stress values of different monitoring sections;
according to the temperature measurement results of all temperature sensing chains around the pipe, calculating the soil temperature at different horizontal and vertical positions around the pipe by using an interpolation method, drawing a contour map and a layered color map of the soil temperature distribution around the pipe, and visually displaying the distribution conditions of the frozen soil temperature at different positions on the soil temperature monitoring section around the pipe on a system display platform, thereby judging the frozen soil distribution area and the freeze-thaw state;
the fourth step: performing pipe-soil interaction analysis; analyzing the correlation between the mechanical state of the pipeline and the freeze-thaw state of frozen soil by combining pipeline strain monitoring data and soil temperature data around the pipeline;
the fifth step: monitoring and early warning analysis is carried out; the data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, issues corresponding early warning information to an early warning information issuing platform according to the proportion of the maximum value of the axial additional tensile stress and the maximum value of the compressive stress of the pipeline, which is obtained by analysis and calculation in the third step, accounts for the allowable value of the axial additional tensile stress and the compressive stress, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message mode through the early warning information issuing platform, and the method comprises the:
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues blue early warning information and automatically pushes the blue early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues yellow early warning information and automatically pushes the yellow early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues red early warning information and automatically pushes the red early warning information to a mobile phone end of an appointed user.
Compared with the prior art, the invention has the following beneficial effects: according to the pipeline stress monitoring system, the pipeline stress state can be directly and accurately mastered by carrying out coupling monitoring on the pipeline body strain and the temperature of the frozen soil around the pipeline, the situation of the frozen soil around the pipeline in the same period can be monitored, basic data support is provided for comprehensively analyzing the interaction between the pipeline and the frozen soil, and meanwhile, the monitoring and early warning subsystem issues early warning information according to the monitoring data, so that the pipeline operation safety is favorably ensured. The invention is provided with strong protection measures, and can avoid the damage of the sensor under the actions of repeated frost heaving and thaw collapse; the temperature sensing chain outer protective layer fixing device is arranged to prevent the outer protective layer from being exposed out of the ground surface due to the influence of frozen soil; an inner protective layer of the temperature sensing chain is provided for repairing the temperature sensing chain if necessary with minimal cost. Meanwhile, the monitoring device can be prepared in advance, the workload of site construction is reduced, and the site installation is convenient. The monitoring and early warning system provided by the invention is safe and reliable, can ensure long-term and stable operation of a monitoring device, provides continuous and effective monitoring data, and timely issues early warning information based on the monitoring data to prevent pipeline accidents caused by frost heaving and thaw collapse.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a permafrost region in an embodiment of the invention.
FIG. 2 is a schematic diagram of a multi-field coupled monitoring subsystem in an embodiment of the invention.
FIG. 3 is a schematic view of a strain sensor installation in an embodiment of the invention.
FIG. 4 is a schematic diagram of a temperature sensing chain structure according to an embodiment of the present invention.
FIG. 5 is a schematic diagram of a second embodiment of the multi-field coupled monitoring subsystem.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
In order to solve the problem that the monitoring elements of the pipeline in the existing frozen soil area are single or the monitoring elements are indirect, the embodiment of the invention provides a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in the frozen soil area, and the technical scheme is as follows:
as shown in fig. 1, the embodiment of the invention provides a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil region.
As shown in fig. 2 and 5, the multi-field coupling monitoring subsystem includes a pipeline strain monitoring device and a soil temperature monitoring device around the pipeline. The pipeline strain monitoring device comprises a strain sensor (the strain sensor can be of a vibrating wire type or a fiber grating type, if the strain sensor is a fiber grating strain sensor, a fiber grating temperature sensor is required to be additionally arranged for temperature compensation), a strain sensor protective cover, a monitoring section protection, a monitoring section leading-out cable and a cable protective pipe; the strain sensor is installed on the surface of the pipeline steel body by using a spot welding technology, a strain sensor protective cover is used for protecting the strain sensor, and an anti-corrosion belt and a cold winding belt are used for protecting the monitoring section; the monitoring section lead-out cable is coiled above the pipeline in an S shape along the axis direction of the pipeline and is protected by a cold winding belt and a rubber plate; leading the cable led out of the monitoring section into an integrated field monitoring station on the earth surface by using an outer protection layer of the temperature sensing chain and a cable protection pipe; in order to effectively calculate the stress distribution of the pipeline 203 in the circumferential direction of the pipeline at a certain monitoring section 201 of the pipeline 203, at least 3 sets of axial strain sensors (if the axial strain sensors are fiber grating strain sensors, fiber grating temperature sensors are required to be additionally arranged for temperature compensation) are installed on one group of monitoring sections 201, the axial strain sensors can be installed at any position of the circumference of the monitoring sections 201, and the axial strain sensors are preferably installed at the top and the left and right sides of the pipeline in order to facilitate field installation and later analysis and calculation. The whole monitoring section 201 is fixed and protected by using an anti-corrosion tape and a cold winding tape, and the extrusion and shearing of soil around the pipe and the sensor and the cable are avoided. The leading-out cable 202 of the monitoring section 201 is S-shaped and is coiled above the pipeline 203 along the axis direction of the pipeline, and is protected by a cold winding belt and a rubber plate, so that the cable is prevented from being extruded and damaged by foreign matters in soil above the pipeline and backfilled in a pipe ditch. The cable led out from the monitoring section 201 is led into an integrated field monitoring station on the earth surface by using the outer protective layer 12 of the temperature sensing chain and the cable protection pipe 204. The monitoring section 201 is a basic unit for pipeline strain monitoring, the number of sections is flexibly designed according to the length of an actual monitoring pipe section, at least 3 groups of monitoring sections are recommended to be arranged in a frozen soil section, and richer pipeline configuration information can be obtained through combined monitoring.
The soil temperature monitoring device around the pipe comprises a temperature sensor (the temperature sensor can be a resistance type, a digital type or a fiber grating type), a temperature sensing chain 13, a heat insulation cushion layer, a temperature sensing chain inner protection layer 11, a temperature sensing chain outer protection layer 12, an outer protection layer fixing expansion anchor, a temperature sensing chain leading-out cable and a cable protection pipe 204.
The temperature sensing chain 13 is formed by connecting a plurality of temperature sensors in parallel by adopting a bus design, and each temperature sensor is insulated and protected; the internal bus of the temperature sensing chain is coiled on the internal reinforcing rib in an S shape, the strength of the temperature sensing chain is increased, frozen soil is prevented from being frozen and expanded, the temperature sensing chain is prevented from being damaged by thawing, sinking and dragging, and a waterproof coat made of a heat conduction material is arranged outside the temperature sensing chain, so that the temperature sensor is prevented from being short-circuited due to water entering the temperature sensing chain; a heat insulation cushion layer is added between the outer part of the temperature sensing chain and the adjacent temperature sensor, so that the influence of air circulation at different layers on the measurement accuracy of the frozen soil temperature is prevented; the inner protection layer 11 of the temperature sensing chain is fixed in the outer protection layer 12 of the temperature sensing chain, the bottom of the inner protection layer is plugged, the top of the inner protection layer is plugged by a waterproof joint, the temperature sensing chain penetrating into the inner protection layer can be prevented from being failed by freezing, and meanwhile, the later-stage temperature sensing chain repair is facilitated; the fixed expansion anchor is arranged at the bottom of the outer protection layer 12 of the temperature sensing chain, so that the outer protection layer of the temperature sensing chain can be fixed at a specified depth of frozen soil, and the phenomenon of freezing and pulling of the outer protection layer of the temperature sensing chain under the repeated freezing swelling and thawing sinking action of the frozen soil can be prevented; the temperature sensing chain lead-out cable is led out from the top of the inner protection layer of the temperature sensing chain by using a waterproof connector and is led into the earth surface integrated field monitoring station by using a cable protection pipe 204.
The pipeline strain monitoring device and the soil temperature monitoring device around the pipeline are introduced into a temperature control cabinet of the earth surface integrated field monitoring station 206 through a cable protection pipe 204, a solar cell panel 205 arranged outside the cabinet and a storage battery in the cabinet supply power to the multi-field coupling monitoring subsystem, 24-hour online measurement of the acquisition equipment is ensured, data are transmitted by data transmission equipment at regular time, and the temperature in the temperature control cabinet is constant.
As shown in fig. 3, the strain sensor 301 is mounted on the surface of the steel body of the pipeline 302 by using a spot welding technology, so that the strain sensor 301 is tightly connected with the steel body of the pipeline 302, and the microscopic deformation of the body of the pipeline 302 is truly reflected; the strain sensor 301 is protected by a strain sensor protective cover, so that the strain sensor 301 is prevented from being out of work due to extrusion of foreign matters such as frozen soil around the pipe; the viscoelastic paste is used for fully covering the outside of the strain sensor protective cover, so that the strain sensor protective cover is waterproof and moistureproof, and prevents water vapor from entering the pipeline 302 to cause corrosion and rusting of the strain sensor. And the outer heat-insulating layer 303 of the pipeline in the frozen soil area is recovered, so that the heat of the pipeline body is reduced to be conducted to the soil around the pipeline.
As shown in fig. 4, the temperature sensing chain is composed of a plurality of temperature sensors 402, and the temperature sensors 402 can be resistive, digital, distributed, or quasi-distributed fiber optic temperature sensors. The built-in strengthening rib of temperature sensing chain can avoid frozen soil frost heaving, melt to sink and pull the effect of dragging and damage temperature sensing chain on the one hand, and on the other hand is convenient for implant the appointed degree of depth in drilling bottom when temperature sensing chain is changed in the later stage. The distance between the temperature sensors 402 and the length of the temperature sensing chain can be flexibly set according to monitoring requirements, the temperature change of seasonal frozen soil layers is obvious, the temperature sensors 402 are suggested to be densely distributed in a degradation significant area, and the sensors can be sparsely distributed in a permanent frozen soil area. A waterproof coat 401 made of heat conduction materials is coated outside the temperature sensing chain, so that the temperature sensor is prevented from being short-circuited due to water entering the temperature sensing chain; a thermal insulation cushion layer 403 is added between the temperature sensors, so that the influence of air circulation of different layers on the measurement accuracy of the frozen soil temperature is avoided. The temperature sensing chain can be customized in advance according to the design, and auxiliary materials can be installed indoors, so that the field installation time is saved. The temperature sensing chain is arranged on the outer surface of the pipeline and in frozen soil around the pipeline. When the outer surface of the pipeline is provided with the temperature sensing chain, the pipe body needs to be excavated and exposed, the temperature sensing chain is arranged around the pipe, and protective measures are added to protect the temperature sensing chain; the temperature sensing chain is led out of the earth surface just above the pipeline by using an outer protection pipe 405, the outer protection pipe is made to be vertical, the pipeline is backfilled, and the backfilled soil is basically level to the top end of the protection pipe.
When the temperature sensing chain is arranged around the pipeline, the temperature sensing chain needs to be positioned on a line perpendicular to the direction of the tubular shaft, and the temperature sensing chain is implanted into the outer-layer protection pipe 405 after the temperature sensing chain is drilled to a specified depth by using a drilling machine. The outer protection tube 405 of the temperature sensing chain is made of ABS materials, and comprises a through hole, a union joint, an elbow, a blank cap and the like, the outer protection tube can be flexibly combined according to the drilling depth, the bottom of the outer protection tube 405 is plugged and provided with an expansion anchor, the bottom expansion anchor can be automatically opened and expanded to grab and buckle the surrounding soil after the outer protection tube is implanted into the specified depth, the bottom of the outer protection tube 405 is fixed, and the phenomenon of frost heaving and frost heaving of the outer protection tube under the repeated frost heaving and thawing sinking action can be effectively prevented.
After the outer protection pipe 405 is fixed, a temperature sensing chain with a heat insulation layer 403 penetrates into the inner protection pipe 404, the bottom end of the inner protection pipe 404 is plugged, and the inner protection pipe 404 is placed into a bottom clamping hole of the outer protection pipe 405 to be fixed. The top end of the inner layer protection pipe 404 is plugged by a waterproof connector, and a cable at the tail end of the temperature sensing chain is led out by the waterproof connector.
The inlayer protection tube 404 can prevent downthehole freezing, if the later stage sensing chain became invalid, but local excavation earth's surface exposes inlayer protection tube 404 top, will damage the sensing chain and pull out the back, implants the temperature sensing chain of the same specification again, can accomplish the sensing chain and restore, and is easy and simple to handle, and on-the-spot earthwork work load is little, and is consuming time and wasting resources when avoiding creeling again.
And leading the cables led out by the longitudinal temperature sensing chains to the temperature control cabinet of the integrated field monitoring station at the position close to the ground surface through underground shallow cable grooves. The temperature sensing chain leads out a cable protection pipe which has good external penetration flexibility, low temperature resistance and corrosion resistance, sand is used for replacement and filling in a cable groove, the damage of the cable caused by frost heaving and thawing sinking of the ground surface is reduced to the maximum extent, and the service life of the temperature sensing chain is prolonged.
The invention is provided with strong protection measures, and can avoid the damage of the sensor under the actions of repeated frost heaving and thaw collapse; the outer protection pipe 405 fixing device of the temperature sensing chain is arranged to prevent the outer protection pipe 405 from being exposed out of the ground due to frozen soil; an inner protective layer 404 of the temperature sensing chain is provided to facilitate repair of the temperature sensing chain at minimal cost, if necessary.
The pipeline strain monitoring section and the soil temperature monitoring section around the pipeline can be flexibly networked according to monitoring environment and monitoring requirements, the heat radiation symmetry is considered for the pipeline with a single heat source, the soil temperature on one side of the monitoring pipeline can reflect the ambient temperature condition of the pipeline, and when sufficient site investigation is carried out, the temperature monitoring section is suggested to be placed in places with higher soil content such as adjacent water and catchment areas. For the case of dual-tube parallel dual heat sources, it is contemplated to provide a temperature monitoring profile in the middle region of the dual-tube parallel.
The field integrated field monitoring station uses an anti-freezing pulling technology, and can effectively prevent the base from being affected by freezing and expansion to expose the earth surface.
The integrated field monitoring station is provided with a temperature control case, a solar power supply device is arranged outside the case, a large-capacity storage battery, a collection instrument, a transmission module and a lightning arrester are arranged in the case, 24-hour online measurement of collection and transmission equipment can be achieved, when the temperature is lower than a set temperature limit value, the temperature of the heat preservation case can be automatically raised, and collection and transmission equipment failure under an extremely cold working condition is avoided.
The monitoring and early warning system is arranged at a designated server side (an entity server or a cloud server), and comprises a data center, a system display platform and an early warning information release platform.
The site can transmit the site monitoring data to a designated server through the data transmission module. In order to prevent the interference of the command signal, the command issued by the upper computer and the data transmitted by the lower computer are encrypted.
After the data center receives the remote sending data, the data are screened, after the data are determined to be accurate, background analysis calculation is carried out, the pipeline stress at any position in the circumferential direction of the pipeline can be automatically calculated, the stress in the circumferential direction of the pipeline of each monitoring section is visually displayed on a system display platform, and the maximum axial stress, the average axial stress and the bending stress value of different monitoring sections are marked; and calculating the soil temperature at different horizontal and vertical positions around the pipeline by using an interpolation method according to the temperature measurement result of each temperature sensing chain around the pipeline, and drawing a contour map and a layered color map of the temperature distribution of the frozen soil around the pipeline in the synchronous monitoring range to display at the system display platform end.
The data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, automatically issues early warning information to an early warning information issuing platform when the axial additional tensile and compressive stress of the pipeline reaches or exceeds a set threshold value, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message form through the early warning information issuing platform.
Example two
On the basis of the first embodiment, as shown in fig. 1, the further embodiment is a multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil region, which comprises a multi-field coupling monitoring subsystem arranged on the field and a monitoring and early warning subsystem arranged at a server end. The multi-field coupling monitoring subsystem comprises a pipeline strain monitoring device and a soil temperature monitoring device around the pipeline. The pipeline strain monitoring device comprises a strain sensor (the strain sensor can be of a vibrating wire type or a fiber grating type, and if the strain sensor is a fiber grating strain sensor, a fiber grating temperature sensor needs to be additionally arranged for temperature compensation), a strain sensor protective cover, a monitoring section protection, a leading-out cable and a cable protective pipe. The strain sensor needs to be installed on the surface of a pipeline steel body, the strain sensor is protected by a strain sensor protective cover, the protective cover is completely covered by viscoelastic paste, the waterproof and moistureproof effects are achieved, and the service life of the sensor is prolonged.
In order to effectively calculate the stress distribution of the pipeline in the circumferential direction of a certain monitoring section of the pipeline, at least 3 sets of strain sensors are installed on one group of monitoring sections (if the fiber grating strain sensors are additionally provided with fiber grating temperature sensors for temperature compensation), and the monitoring sections are fixed and protected by using an anti-corrosion tape and a cold winding tape.
The cable led out from the monitoring section 201 is laid in an S shape along the top of the pipeline axis direction and protected by a cold winding belt and a rubber plate, so that the cable is prevented from being squeezed by foreign matters in soil above the pipeline and damaged after being backfilled by a pipe ditch; the temperature sensing chain outer protective layer 12 and the cable protection tube 204 are used for being introduced into an integrated field monitoring station on the earth surface.
The soil temperature monitoring device around the pipe comprises a temperature sensor (the temperature sensor can be a resistance type, a digital type or a fiber grating type), a temperature sensing chain 13, a temperature sensing chain inner protection layer 11, a temperature sensing chain outer protection layer 12, an outer protection layer fixed expansion anchor, a temperature sensing chain leading-out cable and a cable protection pipe 204. The temperature sensing chain 13 is composed of a plurality of temperature sensors, and the setting distance of the temperature sensors and the setting length of the temperature sensing chain 13 can be flexibly set according to the actual monitoring requirement. The temperature sensing chain 13 is arranged on the outer surface of the pipeline and in the frozen soil around the pipeline. According to symmetry, the top, the side wall and the bottom of the pipeline are respectively provided with a temperature sensor, and the temperature sensors are reasonably distributed from the top of the pipeline to the ground surface according to the buried depth of the pipeline; on the more obvious one side of pipeline influence of being heated, set up many temperature sensing chains along perpendicular pipeline axis direction, temperature sensing chain 13 vertical distribution is in the frozen soil layer, and temperature sensing chain 13 length, temperature sensor set up the density and set up according to actual need. The temperature sensing chain 13 is externally provided with a temperature sensing chain inner protection layer 11, the temperature sensing chain and the inner protection layer are arranged in a temperature sensing chain outer protection layer 12, and the temperature sensing chain outer protection layer 12 is permanently fixed in a frozen soil layer and used for positioning and preventing the temperature sensing chain 13 from being dragged by frozen soil and damaged. The temperature sensing chain 13 is converged into a cable protection pipe at the position close to the earth surface and is led into an earth surface integrated field monitoring station.
The strain sensor lead-out cable and the temperature sensing chain lead-out cable are connected with a strain acquisition instrument or a temperature acquisition instrument in a temperature control cabinet of the integrated field monitoring station, and are connected with a data center at a designated server end through a DTU data transmission module, so that field monitoring data can be transmitted to the data center in real time, and instructions from the data center at the server end can be received and corresponding operations can be executed.
A monitoring and early warning subsystem is arranged at the server side and comprises a data center, a system display platform and an early warning information release platform; after the data center receives the remote sending data, after the data is screened and determined to be accurate and correct, background analysis and calculation are carried out, the pipeline stress at any position in the circumferential direction of the pipeline can be automatically calculated, a pipeline surrounding frozen soil temperature distribution contour map and a layered color map in a synchronous monitoring range are drawn, and the contour map and the layered color map are displayed at a system display platform end; the data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, automatically issues early warning information to the early warning information issuing platform when the axial additional tensile and compressive stress of the pipeline reaches or exceeds a set threshold value, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message mode by the early warning information issuing platform.
The method comprises the following specific steps:
the first step is as follows: the data center records the field pipeline strain monitoring data and the soil temperature monitoring data around the pipeline into a pre-stored database;
the second step is that: and screening the data in the pre-stored database. The data screening is divided into two sub-steps of effective data screening and abnormal data screening. If m data acquisition commands are issued each time data is acquired, and n groups of data are successfully acquired, effective data screening and abnormal data screening are sequentially executed on the n groups of data. The effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data. The abnormal data is screened for the remaining n according to the Grabbs test method2The data acquisition detection level was 5% defining the critical value Gp (n) of the Grabbs test2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And Grabbs per group numberChecking statistical values
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is an abnormal value, the k data needs to be removed, and the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) And if the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the data after the screening of the current measurement result value, and the data screening is ended.
The third step: and analyzing the pipeline strain/stress and the soil temperature field around the pipeline according to the screened data in the second step. Based on the principle of plane section assumption and superposition in the elastic theory, the pipeline strain value of any position of the monitoring section can be calculated according to 3 groups of strain data (3 groups of strain data and 1 group of temperature data when the fiber bragg grating strain monitoring sensor is used) on the monitoring section at the same moment, and the specific calculation process is as follows:
the pipe strain is composed of film strain, y-direction bending strain, and z-direction bending strain. The strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
for the preferred axial strain sensor mounting method mentioned in the first embodiment, it can be obtained that the monitored strain values at the top and left and right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
from the above equations 2-4, the monitored cross-sectional film strain and the maximum y-direction and z-direction bending expressed by the monitored strain are respectively:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
the maximum axial stress, the average axial stress and the bending stress value of each angle of the monitored section can be obtained according to the stress-strain relation curve of the pipeline by the formulas 12 to 14.
According to the temperature measurement results of all temperature sensing chains around the pipe, the soil temperatures at different horizontal and vertical positions around the pipe are calculated by an interpolation method, a contour map and a layered color chart of the soil temperature around the pipe are drawn, the distribution conditions of the frozen soil temperatures at different positions on the soil temperature monitoring section around the pipe are visually represented, and therefore the distribution area and the melting range of the frozen soil are judged.
The fourth step: and performing pipe-soil interaction analysis. And analyzing the correlation between the mechanical state of the pipeline and the freeze-thaw state of the frozen soil by combining the pipeline strain monitoring data and the soil temperature data around the pipeline. Generally speaking, when soil on the surface layer around the pipe melts, the bending stress and the axial stress of the pipeline show an increasing trend, but the stress states of the pipeline are different due to the difference between the melting range and the melting depth of the frozen soil around the pipe at different positions, and the interaction between the distribution condition of the temperature field of the soil around the pipe and the stress state of the pipeline needs to be comprehensively analyzed.
The fifth step: and carrying out monitoring and early warning analysis. The data center synthesizes the pipeline strain analysis result and the temperature distribution of soil around the pipeline, and takes the intrinsic safety monitoring and early warning of the pipeline as a core, and issues corresponding early warning information according to the proportion of the maximum value of the axial additional tensile stress and the maximum value of the compressive stress of the pipeline, which are obtained by analysis and calculation in the third step, to an early warning information issuing platform, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message form through the early warning information issuing platform, and the concrete steps are as follows:
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues blue early warning information and automatically pushes the blue early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues yellow early warning information and automatically pushes the yellow early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues red early warning information and automatically pushes the red early warning information to a mobile phone end of an appointed user.
In conclusion, by carrying out coupling monitoring on the strain of the pipeline body and the temperature of the frozen soil around the pipeline, the stress state of the pipeline can be directly and accurately mastered, the situation of the frozen soil around the pipeline in the same period can be monitored, basic data support is provided for comprehensively analyzing the interaction between the pipeline and the frozen soil, and meanwhile, the monitoring and early warning system issues early warning information according to the monitoring data, so that the safety of pipeline operation is favorably ensured.
The invention is provided with strong protection measures, and can avoid the damage of the sensor under the actions of repeated frost heaving and thaw collapse; the temperature sensing chain outer protective layer fixing device is arranged to prevent the protective layer from being exposed out of the ground due to frozen soil; an inner protective layer of the temperature sensing chain is provided for repairing the temperature sensing chain if necessary with minimal cost. Meanwhile, the monitoring device can be prepared in advance, the workload of site construction is reduced, and the site installation is convenient. The monitoring and early warning system provided by the invention is safe and reliable, can ensure long-term and stable operation of a monitoring device, provides continuous and effective monitoring data, and timely issues early warning information based on the monitoring data to prevent pipeline accidents caused by frost heaving and thaw collapse.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. A multi-field coupling monitoring and early warning system for buried oil and gas pipelines in a frozen soil area is characterized by comprising a multi-field coupling monitoring subsystem arranged on a monitoring field and a monitoring and early warning subsystem arranged at a server end;
the multi-field coupling monitoring subsystem comprises a pipeline strain monitoring device and a soil temperature monitoring device around the pipeline; the pipeline strain monitoring device comprises a strain sensor, a strain sensor protective cover, a monitoring section protection, a monitoring section leading-out cable and a cable protection pipe; the strain sensor is installed on the surface of the pipeline steel body by using a spot welding technology, a strain sensor protective cover is used for protecting the strain sensor, and an anti-corrosion belt and a cold winding belt are used for protecting the monitoring section; the monitoring section lead-out cable is coiled above the pipeline in an S shape along the axis direction of the pipeline and is protected by a cold winding belt and a rubber plate; leading the cable led out of the monitoring section into an integrated field monitoring station on the earth surface by using an outer protection layer of the temperature sensing chain and a cable protection pipe;
the soil temperature monitoring device around the pipe comprises a temperature sensor, a temperature sensing chain, a heat insulation cushion layer, a temperature sensing chain inner protection layer, a temperature sensing chain outer protection layer, an outer protection layer fixing expansion anchor, a temperature sensing chain leading-out cable and a cable protection pipe; the temperature sensing chain is formed by connecting a plurality of temperature sensors in parallel by adopting a bus design, and each temperature sensor is insulated and protected; the internal bus of the temperature sensing chain is coiled on the internal reinforcing rib in an S shape, the strength of the temperature sensing chain is increased, frozen soil is prevented from being frozen and expanded, the temperature sensing chain is prevented from being damaged by thawing, sinking and dragging, and a waterproof coat made of a heat conduction material is arranged outside the temperature sensing chain, so that the temperature sensor is prevented from being short-circuited due to water entering the temperature sensing chain; a heat insulation cushion layer is added between the outer part of the temperature sensing chain and the adjacent temperature sensor, so that the influence of air circulation at different layers on the measurement accuracy of the frozen soil temperature is prevented; the inner protection layer of the temperature sensing chain is fixed in the outer protection layer of the temperature sensing chain, the bottom of the inner protection layer is plugged, the top of the inner protection layer is plugged by a waterproof joint, and the inner protection layer is used for preventing the temperature sensing chain penetrating into the inner protection layer from being failed by freezing and facilitating the later-stage repair of the temperature sensing chain; the bottom of the outer protection layer of the temperature sensing chain is provided with a fixed expansion anchor which is used for fixing the outer protection layer of the temperature sensing chain at a specified depth of frozen soil and preventing the outer protection layer of the temperature sensing chain from being frozen and pulled under the repeated freezing swelling and thawing sinking action of the frozen soil; the temperature sensing chain lead-out cable is led out from the top of the inner protection layer of the temperature sensing chain by using a waterproof connector and is led into the earth surface integrated field monitoring station by using a cable protection pipe.
2. The multi-field coupling monitoring and early warning system for the buried oil and gas pipeline in the frozen soil area as claimed in claim 1, wherein the monitoring and early warning subsystem comprises a data center, a system display platform and an early warning information release platform; after the data center receives the remote sending data and the data are screened and determined to be accurate and correct, background analysis and calculation are carried out, the pipeline stress at any position in the circumferential direction of the pipeline is automatically calculated, a contour map and a layered color map of the temperature distribution of the surrounding frozen soil in the synchronous monitoring range are drawn and displayed on a system display platform; the data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, automatically issues early warning information to an early warning information issuing platform when the axial additional tensile and compressive stress of the pipeline reaches or exceeds a set threshold value, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message form through the early warning information issuing platform.
3. The system of claim 2, wherein the monitoring and early warning subsystem specifically comprises the steps of:
the first step is as follows: the data center records the field pipeline strain monitoring data and the soil temperature monitoring data around the pipeline into a pre-stored database;
the second step is that: screening data in a pre-stored database; the data screening is divided into two sub-steps of effective data screening and abnormal data screening; issuing data acquisition commands for m times when data are acquired each time, and acquiring n groups of data successfully, then performing effective data screening and abnormal data screening on the n groups of data in sequence; the effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data; the abnormal data is screened for the remaining n according to the Grabbs test method2The data acquisition detection level was 5% defining the critical value Gp (n) of the Grabbs test2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And the Grabbs test statistic for each group number
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is an abnormal value, the k data needs to be removed, and the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) If the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the data after the screening of the current measurement result value, and the data screening is ended;
the third step: performing pipeline strain/stress analysis and soil temperature field analysis around the pipeline according to the screened data in the second step; based on the assumption and superposition principle of a flat section in an elasticity theory, the pipeline strain value of any position of the monitoring section is calculated according to 3 groups of strain data on the monitoring section at the same moment, and the specific calculation steps are as follows:
the pipeline strain consists of film strain, y-direction bending strain and z-direction bending strain; the strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
the monitoring strain values of the top and the left and the right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
the monitored cross-sectional film strain and the maximum bending in the y-direction and z-direction, respectively, represented by the monitored strain are obtained from equations 2-4:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
obtaining maximum axial stress, average axial stress and bending stress values of each angle of the monitoring section according to a pipeline stress-strain relation curve by a formula 12-a formula 14, visually displaying the stress of the pipeline in the circumferential direction of each monitoring section on a system display platform, and labeling the maximum axial stress, the average axial stress and the bending stress values of different monitoring sections;
according to the temperature measurement results of all temperature sensing chains around the pipe, calculating the soil temperature at different horizontal and vertical positions around the pipe by using an interpolation method, drawing a contour map and a layered color map of the soil temperature distribution around the pipe, and visually displaying the distribution conditions of the frozen soil temperature at different positions on the soil temperature monitoring section around the pipe on a system display platform, thereby judging the frozen soil distribution area and the freeze-thaw state;
the fourth step: performing pipe-soil interaction analysis; analyzing the correlation between the mechanical state of the pipeline and the freeze-thaw state of frozen soil by combining pipeline strain monitoring data and soil temperature data around the pipeline;
the fifth step: monitoring and early warning analysis is carried out; the data center integrates the pipeline strain analysis result and the temperature distribution of soil around the pipeline, carries out pipeline intrinsic safety monitoring and early warning analysis by taking the pipeline stress analysis result as a main part, issues corresponding early warning information to an early warning information issuing platform according to the proportion of the maximum value of the axial additional tensile stress and the maximum value of the compressive stress of the pipeline, which is obtained by analysis and calculation in the third step, accounts for the allowable value of the axial additional tensile stress and the compressive stress, and automatically pushes the early warning information to a mobile phone end of an appointed user in a short message mode through the early warning information issuing platform, and the method comprises the:
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues blue early warning information and automatically pushes the blue early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues yellow early warning information and automatically pushes the yellow early warning information to a mobile phone end of an appointed user;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, the early warning information issuing platform issues red early warning information and automatically pushes the red early warning information to a mobile phone end of an appointed user.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010613181.0A CN111623733A (en) | 2020-06-30 | 2020-06-30 | Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010613181.0A CN111623733A (en) | 2020-06-30 | 2020-06-30 | Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111623733A true CN111623733A (en) | 2020-09-04 |
Family
ID=72259529
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010613181.0A Pending CN111623733A (en) | 2020-06-30 | 2020-06-30 | Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111623733A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112050971A (en) * | 2020-08-13 | 2020-12-08 | 北京车和家信息技术有限公司 | Cooling loop temperature sensor signal checking method, device, equipment and medium |
| CN112268782A (en) * | 2020-10-22 | 2021-01-26 | 常州大学 | Test device for simulating pipeline mechanical reaction in frozen soil environment |
| CN112393707A (en) * | 2020-11-17 | 2021-02-23 | 中国地质科学院岩溶地质研究所 | Shallow soil cave recognition early warning device and using method thereof |
| CN113155015A (en) * | 2021-03-24 | 2021-07-23 | 中国石油大学(华东) | Strain monitoring method and system during pipeline operation |
| CN114199679A (en) * | 2021-12-09 | 2022-03-18 | 南京大学 | Optical fiber drawing-based distributed in-situ testing device and method for frozen soil multi-physical-property parameters |
| CN116296856A (en) * | 2023-05-17 | 2023-06-23 | 国网吉林省电力有限公司辽源供电公司 | Frozen soil detection device and method for power transmission and distribution in northern severe cold region |
| CN117366481A (en) * | 2023-12-08 | 2024-01-09 | 中国科学院西北生态环境资源研究院 | Device and method for monitoring moving distance of buried heating oil pipeline in permafrost region |
-
2020
- 2020-06-30 CN CN202010613181.0A patent/CN111623733A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112050971A (en) * | 2020-08-13 | 2020-12-08 | 北京车和家信息技术有限公司 | Cooling loop temperature sensor signal checking method, device, equipment and medium |
| CN112050971B (en) * | 2020-08-13 | 2023-02-28 | 北京车和家信息技术有限公司 | Cooling loop temperature sensor signal checking method, device, equipment and medium |
| CN112268782A (en) * | 2020-10-22 | 2021-01-26 | 常州大学 | Test device for simulating pipeline mechanical reaction in frozen soil environment |
| CN112393707A (en) * | 2020-11-17 | 2021-02-23 | 中国地质科学院岩溶地质研究所 | Shallow soil cave recognition early warning device and using method thereof |
| CN113155015A (en) * | 2021-03-24 | 2021-07-23 | 中国石油大学(华东) | Strain monitoring method and system during pipeline operation |
| CN114199679A (en) * | 2021-12-09 | 2022-03-18 | 南京大学 | Optical fiber drawing-based distributed in-situ testing device and method for frozen soil multi-physical-property parameters |
| CN116296856A (en) * | 2023-05-17 | 2023-06-23 | 国网吉林省电力有限公司辽源供电公司 | Frozen soil detection device and method for power transmission and distribution in northern severe cold region |
| CN116296856B (en) * | 2023-05-17 | 2023-08-01 | 国网吉林省电力有限公司辽源供电公司 | Frozen soil detection device and method for power transmission and distribution in northern severe cold region |
| CN117366481A (en) * | 2023-12-08 | 2024-01-09 | 中国科学院西北生态环境资源研究院 | Device and method for monitoring moving distance of buried heating oil pipeline in permafrost region |
| CN117366481B (en) * | 2023-12-08 | 2024-02-06 | 中国科学院西北生态环境资源研究院 | Device and method for monitoring moving distance of buried heating oil pipeline in permafrost region |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111623733A (en) | Multi-field coupling monitoring and early warning system for underground oil and gas pipelines in frozen soil area | |
| Wang et al. | Pipeline–permafrost interaction monitoring system along the China–Russia crude oil pipeline | |
| CN109736895A (en) | A kind of tunnel deformation warning monitoring system | |
| CN103591982B (en) | A kind of monitoring method of electric power tunnel structure problem | |
| CN111609808A (en) | Deformation monitoring system for oil-gas pipeline of water-sealed tunnel | |
| CN112504336A (en) | Landslide area pipeline deformation monitoring system | |
| CN105806311A (en) | Optical fiber slope dam displacement settlement monitoring system | |
| RU2571497C1 (en) | Method to monitor technical state of above-surface pipelines under permafrost conditions | |
| CN104236623A (en) | Multifunctional automated monitoring system for frost heaving of water conveyance canal | |
| Inaudi et al. | Long-range pipeline monitoring by distributed fiber optic sensing | |
| CN109853578B (en) | Foundation pit structure with real-time monitoring and early warning functions and construction method thereof | |
| CN108225265A (en) | A kind of soft soil roadbed deformation remote comprehensive monitoring system and installation method | |
| CN113450542B (en) | Real-time monitoring system and method for rock soil water content below urban traffic key road | |
| CN204479065U (en) | A kind of High Precision Traverses formula tunneling boring stability of slope monitor and early warning system | |
| CN207799866U (en) | A kind of strike-slip fault High Cut Slope safety monitoring system based on high and cold mountain area | |
| CN113007611A (en) | Monitoring system for gas pipeline crossing river bottom | |
| CN103195072B (en) | Algorithm for speculating freezing curtain development situation | |
| CN211504049U (en) | Multi-field coupling monitoring and early warning device for underground oil and gas pipelines in frozen soil area | |
| CN212721525U (en) | Deformation and leakage monitoring system for long-distance heat-insulation conveying pipeline | |
| CN113091826B (en) | Multifunctional device for monitoring geological environment of coal mining subsidence area | |
| Inaudi et al. | Distributed fiber-optic sensing for long-range monitoring of pipelines | |
| CN213748552U (en) | Landslide area pipeline deformation monitoring system | |
| CN102677645A (en) | Multi-field coupling real-time sensing method for horizontal frozen soil | |
| CN115355056A (en) | Automatic monitoring system for stress performance of urban railway river-crossing tunnel composite lining structure | |
| CN210775478U (en) | Soil freezing depth testing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |