Online tracking and positioning method for natural gas pipeline cleaner in mountainous area

Abstract

The invention provides an online tracking and positioning method for a natural gas pipeline cleaner in a mountainous area, and belongs to the field of natural gas pipeline maintenance. According to the method, the theoretical operation time of the pipe cleaner is calculated, the moment when the pipe cleaner reaches a valve chamber is estimated, a pressure sensor and a flow sensor at the two ends of the valve chamber are monitored in combination with an SCADA system, when the pipe cleaner passes through the valve chamber, the sensors will generate pressure and flow fluctuation, and whether the pipe cleaner passes through the valve chamber or not is judged according to whether the pressure and the flow fluctuate or not; when the pipe cleaner does not normally pass through the valve chamber, the position of the pipe cleaner is calculated through numerical simulation, and whole-course tracking and positioning of the pipe cleaner are achieved. The method can track and position the pipe cleaner in the natural gas pipeline in the mountainous area, reduces the tracking difficulty of a tracking vehicle caused by complex terrain in the mountainous area, reduces the risk of tracking personnel, reduces the probability of blockage accidents of the pipe cleaner caused by more hydrate slurry in the natural gas pipeline in the mountainous area, and ensures the safe operation of the pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of pig identification and positioning during natural gas pipeline pigging, and in particular to an online tracking and positioning method that identifies whether a pig has passed through a valve chamber based on a SCADA system and the pressure and flow fluctuations caused by the pig passing through the valve chamber, and locates the pig by numerical simulation if the pig has not passed through, thereby identifying whether the pig is operating normally. Background Art

[0002] Mountain natural gas pipelines usually pass through areas with complex terrain and changeable climates. After the construction of such pipelines is completed, they still need later maintenance. The transportation of large equipment such as pipeline cleaning equipment and pipeline inspection equipment requires a lot of manpower and material resources, and also faces the safety issues of operators. At the same time, the terrain of mountain pipelines is undulating, and there will be frequent temperature and pressure changes when laying over long distances, which will easily lead to a large amount of accumulated liquid and hydrates in the pipeline. The presence of accumulated liquid will accelerate the formation of hydrates, and the formation of hydrates will lead to a decrease in the flow area of ​​the pipeline, and eventually lead to pipeline blockage, seriously endangering the safe operation of the pipeline. Therefore, regular pipeline cleaning operations are required to ensure the normal operation of the pipeline.

[0003] During the pipe cleaning operation, the pipe cleaner will push sediments such as accumulated liquid and hydrates forward. At this time, the main sediments in the natural gas pipeline are accumulated liquid and hydrates, which combine to form natural gas slurry. The presence of slurry accelerates the formation of hydrates, resulting in faster pipeline blockage. On the other hand, it hinders the normal operation of the pipe cleaner in the pipeline. In mountainous pipelines, pipe cleaner operations also need to face complex environments such as height differences, sharp bends, and inclined sections, which also increase the risk of pipe cleaner blockage or damage. If the pipe cleaner is blocked in the mountainous pipeline but is not discovered and handled in time, natural gas will not be able to pass normally, resulting in increased pipeline pressure and reduced flow, which may eventually lead to pipeline overpressure, cause pipe bursts and generate a large number of leaks, while affecting the gas supply to downstream users. Therefore, it is necessary to monitor the operating status of the pipe cleaner in real time to ensure that the pipe cleaner can be discovered in time when it is blocked in the mountainous pipeline and take corresponding measures. Summary of the invention

[0004] The technical problem to be solved by the present invention is that in the prior art, it is difficult to conduct real-time monitoring and data transmission of a pipe cleaner in a natural gas pipeline cleaning operation in a mountainous area, and the pipe cleaner cannot be tracked and positioned in real time. A method for online tracking and positioning of a pipe cleaner is provided, which can utilize a SCADA system and numerical simulation.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: an online tracking and positioning method for a natural gas pipeline pig in a mountainous area, comprising:

[0006] S1. Obtain the valve chamber pipeline pressure, volume flow, pipeline inner diameter and the pipe length between the two valve chambers through the SCADA system;

[0007] S2. The running speed of the natural gas pipeline pig is generally 3 to 6 m / s. The running speed of the pig is determined based on the on-site construction experience, and the estimated time for the pig to pass between the valve chambers is obtained based on the length of the pipeline between the valve chambers;

[0008] S3. The pig enters the first valve chamber and the first moment of its start is recorded;

[0009] S4. The sum of the first moment and the estimated time for the pig to pass between the valve chambers is the second moment;

[0010] S5. Before the deviation threshold of the estimated time is added to the second moment, the pressure information and flow information of the sensors upstream and downstream of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pressure and flow fluctuate at the same time, it indicates that the pig passes through the valve chamber normally. If the pig does not reach the end point, this moment is recorded as the first moment, and the actions of S1-S4 are repeated;

[0011] S6. After adding the estimated time deviation threshold at the second moment, the pressure information and flow information of the sensors upstream and downstream of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pressure and flow do not fluctuate at the same time, it indicates that the pig may be blocked;

[0012] S7. Establish a numerical simulation model for natural gas flow in pipelines, including the PR gas state equation, continuity equation, and momentum equation; establish the pig motion equation; introduce the continuity equation and momentum equation of natural gas hydrate slurry;

[0013] S8. Use the natural gas pipeline SCADA system to collect the real-time pressure and flow data of the pipeline inlet and outlet as the boundary conditions of the equations in S7, and couple and solve the equations in S7 to finally obtain the running speed of the pig;

[0014] S9. Calculate the pig speed in real time, and calculate the distance the pig runs in the pipeline according to the formula, and finally obtain the position of the pig at a certain moment;

[0015] S10. Locate the position of the pig in real time until the pig passes through the valve chamber accurately, record the time and update it as the first time, and repeat the actions of S1-S9 until the entire pipeline cleaning operation is completed;

[0016] The beneficial effect of the technical solution of the present invention is as follows: the pressure-flow data of the pipe cleaner when passing through the valve chamber is monitored on the natural gas pipeline equipped with SCADA. When the pipe cleaner passes through the valve chamber, the pipeline pressure and flow will fluctuate. The passage of the pipe cleaner is identified by this feature. The estimated running time of the pipe cleaner from the upstream valve chamber to the downstream valve chamber is calculated by the running speed of the pipe cleaner and the pipe length between the valve chambers. According to the time when the pipe cleaner passes through the upstream valve chamber, the time when the pipe cleaner starts to count through the valve chamber, the estimated running time and the running time deviation threshold are combined for analysis to determine whether the pipe cleaner passes through the valve chamber. If the pipe cleaner does not pass through the valve chamber at the expected time, numerical simulation is used to track and locate the pipe cleaner until the pipe cleaner passes through the valve chamber normally. The running dynamics of the pipe cleaner can be timely understood to avoid the serious consequences caused by the blockage of the pipe cleaner due to failure to be discovered in time.

[0017] Further, S2 includes: S21, taking the pig running speed v according to the on-site construction experience. S22, calculating the time for the pig to pass through the two valve chambers according to the following formula: ΔT=L / v, where ΔT is the time for the pig to pass through the two valve chambers, L is the length of the pipeline between the valve chambers, m; v is the running speed, m / s.

[0018] The beneficial effect of adopting the above further technical scheme is: according to the expected running speed of the pipe cleaner, the expected running time of the pipe cleaner from the upstream valve chamber to the downstream valve chamber is calculated according to the running speed and the pipeline length between the upstream and downstream valve chambers, the time when the pipe cleaner arrives at the valve chamber is predicted in advance, the accuracy of the running time of the pipe cleaner is improved, the running status of the pipe cleaner is judged in time, and the operator is convenient to take corresponding measures in time.

[0019] Furthermore, the present invention adopts a SCADA system equipped with a natural gas pipeline to monitor the flow and pressure of a remote pipeline, including: a pipeline, two sensors for monitoring the flow of the pipeline upstream and downstream of the valve chamber, two sensors for monitoring the pressure of the pipeline upstream and downstream of the valve chamber, multiple data acquisition modules for collecting the output signals of the sensors and selecting a suitable communication protocol, configuring the communication interface and processing and converting the original data into a usable format, a communication module for transmitting the data to a remote control center through a wired network or a wireless network, a controller for processing and controlling the collected data, and a remote monitoring center for receiving and storing data from the field. The flow sensor and the pressure sensor are both installed on the upstream and downstream pipelines of the valve chamber, the data acquisition module is connected to the flow sensor, the data acquisition module is connected to the pressure sensor, the data acquisition module is connected to the communication module, the communication module is connected to the controller, the controller is connected to the remote control center, the flow sensor obtains the flow information of the pipeline, the pressure sensor obtains the pressure information of the pipeline, and the remote monitoring center obtains the pipe length between the valve chambers, the inner diameter of the pipeline, the first moment when the pig enters the valve chamber, and the second moment when the pig enters the downstream valve chamber.

[0020] The beneficial effect of adopting the above-mentioned further technical solution is: the SCADA system is used to transmit the flow and pressure of the pipeline to the control center in real time, and the control center monitors the fluctuations of flow and pressure, captures the flow and pressure information of the pipeline in real time, and accurately analyzes the operating position of the pipe cleaner, which can reduce the influence of the complex environment in mountainous areas, reduce the operation of manpower and vehicles, and greatly reduce tracking costs.

[0021] Further, S5 includes S51, a method for the pig to pass through the valve chamber normally, characterized in that during the normal operation of the pig, when passing through the valve, a blockage is formed in front of the valve, the fluid cannot flow freely, the pressure indicator in front of the valve will rise, after the pig passes through the pressure indicator in front of the valve, the pig blocks the flow of a part of the fluid, causing the pressure indicator behind the valve to drop, when the pig passes through the pressure indicator behind the valve, a new blockage is formed behind the valve, the pressure indicator behind the valve will rise, after the pig completely passes through the valve, the resistance of the fluid is increased, The pressure before and after the valve will increase; S52, the method for the pipe cleaner to pass through the valve chamber normally, characterized in that when the pipe cleaner is operating normally, when it passes through the flow indicators before and after the valve, the operation of the pipe cleaner increases the resistance to the flow of the fluid in the pipeline, and the flow rate decreases. When the pipe cleaner passes the flow indicator, the resistance decreases and the flow rate returns to normal; S53, when the time when the above phenomenon occurs is before the second moment plus the estimated time ΔT deviation threshold, it indicates that the pipe cleaner passes through the valve chamber normally. If the pipe cleaner does not reach the end point, the moment is recorded as the first moment T1, and the actions of S1-S4 are repeated.

[0022] The beneficial effect of adopting the above further technical solution is: by analyzing the pressure and flow fluctuations when the pig passes through the valve, it is accurately determined whether the pig passes through the valve chamber.

[0023] Furthermore, in S6, after the estimated time ΔT deviation threshold is added to the second moment, the natural gas pipeline SCADA system fails to detect flow and pressure fluctuations upstream and downstream of the valve chamber, indicating that the pipe cleaner has not passed through the valve chamber at the expected time. It is necessary to locate the pipe cleaner in time to determine whether the pipe cleaner is stuck.

[0024] The beneficial effect of adopting the above further technical solution is: by observing the flow and pressure fluctuations in the valve chamber during the expected arrival time of the pipe cleaner, preparations are made in advance to determine the position of the pipe cleaner. If no flow and pressure fluctuations occur, it is necessary to position the pipe cleaner between the valve chambers, perform numerical simulation of the pipeline between the valve chambers, calculate the position of the pipe cleaner, and promptly judge the operating status of the pipe cleaner, while ensuring the normal operation of the pipe cleaner.

[0025] Further, S7 includes, S71, PR state equation to calculate the density of natural gas in the pipeline; S72, natural gas pipeline continuity equation to calculate the tail velocity of the pig; S73, natural gas pipeline momentum equation to calculate the tail pressure P1 of the pig in the natural gas pipeline; S74, hydrate slurry continuity equation to calculate the tail velocity of the slurry; S75, hydrate slurry momentum equation to calculate the head pressure P2 of the pig; S76, pig motion equation to calculate the pig motion velocity.

[0026] The beneficial effect of adopting the above further technical solution is that: by calculating by combining various equations, the running speed of the pipe cleaning device is obtained, and whether the pipe cleaning device is in a normal operating state can be judged.

[0027] Furthermore, in S8, when the pipe cleaner fails to pass through the valve chamber within the expected time, the pipeline pressure and flow information in the valve chamber obtained by SCADA is used as the boundary condition of the equation in S7, and the PR gas state equation, the continuity equation in the natural gas pipeline, the momentum equation, the hydrate slurry continuity equation, the momentum equation, and the pipe cleaner motion equation of S7 are solved jointly to obtain the running speed of the pipe cleaner, and the running status of the pipe cleaner at this time is judged by the running speed of the pipe cleaner.

[0028] The beneficial effect of adopting the above further technical solution is that through the timely discovery of the control center and the calculation of numerical simulation, the operating status of the pipe cleaner can be judged in time, the consumption of manual work can be reduced, and the cost can be saved.

[0029] Furthermore, in S9, according to the running speed of the pipe cleaner and the distance of the pipe cleaner movement calculated by numerical simulation at the previous moment, the distance of the pipe cleaner at the next moment is calculated according to the formula, and the calculation is repeated iteratively until the pipe cleaner passes through the valve chamber.

[0030] The beneficial effect of adopting the above further technical solution is: through real-time tracking of the position of the pig, the tracking and positioning of the pig in the mountainous pipeline is achieved, the efficiency of the pigging operation is improved, and the probability of accidents is reduced.

[0031] Furthermore, the setting of the estimated time deviation threshold takes into account the layout of pipelines in mountainous areas (the pipelines have complex layouts such as bends, branches, height differences, etc.), the influence of fluid media (parameters such as flow rate, pressure, viscosity of the fluid in the pipeline are unstable or different from expectations), the internal conditions of the pipeline (the pipeline may have corrosion, scaling, deformation, deposits, etc.), and problems with the pipe cleaner itself (poor sealing performance, structural damage or quality problems).

[0032] The beneficial effect of adopting the above further technical solution is: setting the deviation threshold according to the actual situation encountered by the pig when running in the pipeline, thereby improving the accuracy of the prediction.

[0033] Furthermore, in S10, after the above steps, the pig passes through the valve chamber normally. At this time, the time when the pig passes through the valve chamber is recorded and updated to the first moment of S3, and the actions of S1 to S9 are repeated.

[0034] The beneficial effect of adopting the above further technical solution is: accurately locating the specific position of the pipe cleaning device in the pipeline and tracking it in each valve chamber interval until the pipe cleaning is completed, thereby improving the effectiveness of the method.

[0035] Beneficial effects:

[0036] The present invention obtains the valve chamber pipeline volume flow, valve chamber pipeline pressure, and pipe length between two valve chambers through the SCADA system, calculates the estimated time for the pipe cleaner to pass between the valve chambers, and records the first moment when the pipe cleaner enters the first valve chamber. The second moment is obtained according to the first moment and the estimated time. The pipeline pressure and flow information collected upstream and downstream of the valve chamber are obtained at different time periods to determine whether the pipe cleaner is operating normally or blocked. If blocked, the pipe cleaner is tracked and located by a numerical simulation method until the first moment is updated when the pipe cleaner accurately passes through the valve chamber. The above actions are repeated until the entire pipeline cleaning operation is completed. The invention solves the problem that the pipe cleaner cannot be tracked and located in real time during the cleaning of the natural gas pipeline in mountainous areas, and the problem that the blockage of the pipe cleaner cannot be discovered and handled in time due to the large amount of hydrate slurry in the natural gas pipeline in mountainous areas. The invention also solves the problem that the vehicle tracking or manual monitoring of the natural gas pipeline in mountainous areas has high maintenance costs and the safety of construction personnel cannot be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flowchart of online tracking and positioning of a pig for a natural gas pipeline in a mountainous area provided by the present invention.

[0038] Figure 2 This is a schematic diagram of the boundary during the pig's forward movement. DETAILED DESCRIPTION

[0039] like Figure 1 As shown, an embodiment of the present invention provides an online tracking and positioning method for a natural gas pipeline pig in a mountainous area, comprising:

[0040] S1. Obtain the valve chamber pipeline pressure, volume flow, pipeline inner diameter and the pipe length between the two valve chambers through the SCADA system;

[0041] S2. The running speed of the natural gas pipeline pig is generally 3 to 6 m / s. The running speed of the pig is determined based on the on-site construction experience. According to the length of the pipeline between the valve chambers, the estimated time ΔT for the pig to pass between the valve chambers is obtained;

[0042] S3. The pig enters the first valve chamber and the first moment T1 is recorded;

[0043] S4. The sum of the first moment and the estimated time ΔT for the pig to pass between the valve chambers is the second moment T2;

[0044] S5. Before the deviation threshold of the estimated time ΔT is added to the second moment, the pressure information and flow information of the sensors upstream and downstream of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pressure and flow fluctuate at the same time, it indicates that the pig passes through the valve chamber normally. If the pig does not reach the end point, the moment is recorded as the first moment T1, and the actions of S1-S4 are repeated;

[0045] S6. After adding the estimated time ΔT deviation threshold at the second moment, the pressure information and flow information of the upstream and downstream sensors of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pressure and flow do not fluctuate at the same time, it indicates that the pig may be blocked;

[0046] S7. Establish a numerical simulation model for natural gas flow in pipelines, including the PR gas state equation, continuity equation, and momentum equation; establish the pig motion equation; introduce the continuity equation and momentum equation of natural gas hydrate slurry;

[0047] S8. Use the natural gas pipeline SCADA system to collect the real-time pressure and flow data of the pipeline inlet and outlet as the boundary conditions of the equations in S7, and couple and solve the equations in S7 to finally obtain the running speed of the pig;

[0048] S9. Calculate the pig speed in real time and use the formula Calculate the distance the pig runs in the pipeline and finally get the position of the pig at a certain moment;

[0049] S10. Locate the position of the pig in real time until the pig passes through the valve chamber accurately, record the time and update it as the first time T1, and repeat the actions of S1-S9 until the entire pipeline cleaning operation is completed;

[0050] The beneficial effect of the technical solution of the present invention is as follows: the pressure-flow data of the pipe cleaner passing through the valve chamber is monitored on the natural gas pipeline equipped with SCADA. When the pipe cleaner passes through the valve chamber, the pipeline pressure and flow will fluctuate. The passage of the pipe cleaner is identified by this feature. The estimated running time of the pipe cleaner from the upstream valve chamber to the downstream valve chamber is calculated by the running speed of the pipe cleaner and the pipe length between the valve chambers. According to the time when the pipe cleaner passes through the upstream valve chamber, the time when the pipe cleaner starts to count through the valve chamber, the estimated running time and the running time deviation threshold are combined for analysis to determine whether the pipe cleaner passes through the valve chamber. If the pipe cleaner does not pass through the valve chamber at the expected time, numerical simulation is used to track and locate the pipe cleaner until the pipe cleaner passes through the valve chamber normally. The running dynamics of the pipe cleaner can be timely understood to avoid the serious consequences caused by the blockage of the pipe cleaner due to failure to be discovered in time.

[0051] The embodiment provided by the present invention provides an online tracking and positioning method for a natural gas pipeline pig in a mountainous area. The method calculates the estimated time for the pig to pass through the valve chamber, combines the pressure and flow fluctuation signals of the pig passing through the valve chamber, and preliminarily determines whether the pig has passed through the valve chamber. If it has not passed through the valve chamber, the pipeline pig is tracked and positioned through numerical simulation to promptly clarify the operating status of the pig.

[0052] Further, S2 includes: S21, taking the pig running speed v according to the on-site construction experience. S22, calculating the time for the pig to pass through the two valve chambers according to the following formula: ΔT=L / v, where ΔT is the time for the pig to pass through the two valve chambers, L is the length of the pipeline between the valve chambers, m; v is the running speed, m / s.

[0053] The beneficial effect of adopting the above further technical scheme is: according to the expected running speed of the pipe cleaner, the expected running time of the pipe cleaner from the upstream valve chamber to the downstream valve chamber is calculated according to the running speed and the pipeline length between the upstream and downstream valve chambers, the time when the pipe cleaner arrives at the valve chamber is predicted in advance, the accuracy of the running time of the pipe cleaner is improved, the running status of the pipe cleaner is judged in time, and the operator is convenient to take corresponding measures in time.

[0054] Furthermore, the present invention adopts a SCADA system equipped with a natural gas pipeline to monitor the flow and pressure of a remote pipeline, including: a pipeline, two sensors for monitoring the flow of the pipeline upstream and downstream of the valve chamber, two sensors for monitoring the pressure of the pipeline upstream and downstream of the valve chamber, multiple data acquisition modules for collecting the output signals of the sensors and selecting a suitable communication protocol, configuring the communication interface and processing and converting the original data into a usable format, a communication module for transmitting the data to a remote control center through a wired network or a wireless network, a controller for processing and controlling the collected data, and a remote monitoring center for receiving and storing data from the field. The flow sensor and the pressure sensor are both installed on the upstream and downstream pipelines of the valve chamber, the data acquisition module is connected to the flow sensor, the data acquisition module is connected to the pressure sensor, the data acquisition module is connected to the communication module, the communication module is connected to the controller, the controller is connected to the remote control center, the flow sensor obtains the flow information of the pipeline, the pressure sensor obtains the pressure information of the pipeline, and the remote monitoring center obtains the pipe length between the upstream valve chamber and the downstream valve chamber, the inner diameter of the pipeline, the first moment when the pig enters the valve chamber, and the second moment when the pig enters the downstream valve chamber.

[0055] The beneficial effect of adopting the above-mentioned further technical solution is: the SCADA system is used to transmit the flow and pressure of the pipeline to the control center in real time, and the control center monitors the fluctuation of flow and pressure, captures the flow and pressure information of the pipeline in real time, and analyzes the operating position of the pipe cleaner, which can be unaffected by the external environment, reduce the operation of manpower and vehicles, and greatly reduce the tracking cost.

[0056] Further, S5 includes S51, a method for the pig to pass through the valve chamber normally, characterized in that during the normal operation of the pig, when passing through the valve, a blockage is formed in front of the valve, the fluid cannot flow freely, the pressure indicator in front of the valve will rise, after the pig passes through the pressure indicator in front of the valve, the pig blocks the flow of a part of the fluid, causing the pressure indicator behind the valve to drop, when the pig passes through the pressure indicator behind the valve, a new blockage is formed behind the valve, the pressure indicator behind the valve will rise, after the pig completely passes through the valve, the resistance of the fluid is increased, The pressure before and after the valve will increase; S52, the method for the pipe cleaner to pass through the valve chamber normally, characterized in that when the pipe cleaner is operating normally, when it passes through the flow indicators before and after the valve, the operation of the pipe cleaner increases the resistance to the flow of the fluid in the pipeline, and the flow rate decreases. When the pipe cleaner passes the flow indicator, the resistance decreases and the flow rate returns to normal; S53, when the time when the above phenomenon occurs is before the second moment plus the estimated time ΔT deviation threshold, it indicates that the pipe cleaner passes through the valve chamber normally. If the pipe cleaner does not reach the end point, the moment is recorded as the first moment T1, and the actions of S1-S4 are repeated.

[0057] When the pig passes through the valve chamber normally, the time when the pig passes through the valve chamber is redefined as the first moment of S3, S6-S9 are ignored, and the process directly jumps to S10.

[0058] The beneficial effect of adopting the above further technical solution is: according to the analysis of the pressure and flow fluctuation when the pig passes through the valve, it is accurately determined whether the pig passes through the valve chamber, and the pig position is updated in time.

[0059] Furthermore, in S6, after the estimated time ΔT deviation threshold is added at the second moment, the natural gas pipeline SCADA system fails to detect flow and pressure fluctuations upstream and downstream of the valve chamber, indicating that the pipe cleaner did not pass through the valve chamber at the expected time and may be stuck in the operating range.

[0060] The beneficial effect of adopting the above further technical scheme is: by observing the flow and pressure fluctuations in the valve chamber within the expected arrival time of the pipe cleaner, preparations are made in advance to determine the position of the pipe cleaner. If no flow and pressure fluctuations occur, blockage may occur, and the pipe cleaner needs to be positioned between the valve chambers in time. By performing numerical simulation of the pipeline between the valve chambers, the position of the pipe cleaner is calculated, the operating status of the pipe cleaner is judged in time, and the normal operation of the pipe cleaner is ensured.

[0061] Furthermore, the estimated time deviation threshold is 10% of the estimated time ΔT, taking into account the layout direction of pipelines in mountainous areas (the pipelines have complex layouts such as bends, branches, height differences, etc.), the influence of fluid media (parameters such as flow rate, pressure, viscosity of the fluid in the pipeline are unstable or different from expectations), the internal conditions of the pipeline (the pipeline may have corrosion, scaling, deformation, deposits, etc.), and the problems of the pipe cleaner itself (poor sealing performance, structural damage or quality problems).

[0062] In the embodiment of the present invention, the estimated time deviation threshold is tentatively determined to be 10% of the estimated time ΔT. It should be noted that the estimated time deviation threshold can be adjusted according to actual conditions. For example, when the length of the pipeline between the valve chambers is short, it can be set to 5%, and when the length of the pipeline between the pipeline valve chambers is long, it can be set to 15% or 20%.

[0063] The beneficial effect of adopting the above further technical solution is: setting the deviation threshold according to the actual situation encountered by the pig when running in the pipeline, thereby improving the accuracy of the prediction.

[0064] Further, in S7, according to the attached Figure 2 As shown in the figure, the density of natural gas in the pipeline is calculated according to the PR state equation, and the adjacent Figure 2 The velocity at points 2 and 4 is calculated based on the momentum equation of natural gas pipeline flow. Figure 2 The pressure at point 2 (P1) and point 4 is used to calculate the pressure at point 3 (P2) based on the continuity equation and momentum equation of the hydrate slurry. The speed of the pig is calculated based on the head pressure P1 and tail pressure P2 of the pig combined with the pig motion equation.

[0065] The beneficial effect of adopting the above further technical solution is that: by calculating by combining various equations, the running speed of the pipe cleaning device is obtained, and whether the pipe cleaning device is in a normal operating state can be judged.

[0066] Furthermore, in S8, when the pipe cleaner fails to pass through the valve chamber within the expected time, the pressure flow information obtained by SCADA is used as the boundary condition of the equation in S7, and the PR gas state equation, the continuity equation in the natural gas pipeline, the momentum equation, the hydrate slurry continuity equation, the momentum equation, and the pipe cleaner motion equation of S7 are solved together to obtain the running speed of the pipe cleaner, and the running state of the pipe cleaner at this time is judged by the running speed of the pipe cleaner until the pipe cleaner passes through the valve chamber normally. At this time, the time of passing through the valve chamber is recorded and updated to the first moment of S3, and the actions of S1-S9 are repeated.

[0067] The beneficial effect of adopting the above further technical solution is: accurately locating the specific position of the pipe cleaning device in the pipeline and tracking it in each valve chamber interval until the pipe cleaning is completed, thereby improving the effectiveness of the method.

[0068] Finally, it should be pointed out that the above content is only a preferred implementation case of the present invention and is not intended to limit the present invention. As long as it is within the spirit and principle of the present invention, any modification, equivalent substitution, improvement, etc. should be included in the scope of protection of the present invention.

Claims

1. A method for online tracking and positioning of a natural gas pipeline pig in a mountainous area, characterized in that: include: S1. Obtain the valve chamber pipeline pressure, volume flow, pipeline inner diameter and the pipe length between the two valve chambers through the SCADA system; S2. The running speed of the natural gas pipeline pig is generally 3 to 6 m / s. The running speed of the pig is determined based on the on-site construction experience. According to the length of the pipeline between the valve chambers, the estimated time ΔT for the pig to pass between the valve chambers is obtained; S3. The pig enters the first valve chamber and records the first moment T1 of the start; S4. The sum of the first moment and the estimated time ΔT for the pig to pass between the valve chambers is the second moment T2; S5. Before the deviation threshold of the estimated time ΔT is added to the second moment, the pipeline pressure information and pipeline flow information of the upstream and downstream sensors of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pipeline pressure and pipeline flow fluctuate at the same time, it indicates that the pig passes through the valve chamber normally. If the pig does not reach the end point, the moment is recorded as the first moment T1, and the actions of S1-S4 are repeated; S6. After adding the estimated time ΔT deviation threshold at the second moment, the pipeline pressure information and pipeline flow information of the upstream and downstream sensors of the valve chamber are obtained through the natural gas pipeline SCADA system. When the pipeline pressure and pipeline flow do not fluctuate at the same time, it indicates that the pig may be blocked; S7. Establish a simulation mathematical model for natural gas flow in the pipeline, including the PR gas state equation, continuity equation, and momentum equation; establish the pig motion equation; introduce the continuity equation and momentum equation of natural gas hydrate slurry; S8. Use the natural gas pipeline SCADA system to collect the real-time pipeline pressure and real-time pipeline flow data at the pipeline inlet and outlet in real time as the boundary conditions of the equation in S7, and couple and solve the various equations in S7 to finally obtain the running speed of the pig; S9. Calculate the pig speed in real time and use the formula Calculate the distance the pig runs in the pipeline and finally get the position of the pig at a certain moment; S10. Locate the position of the pipe cleaner in real time until the pipe cleaner passes through the valve chamber accurately, record this moment and update it as the first moment T1, and repeat the actions of S1 to S9 until the entire pipeline cleaning operation is completed.

2. The method for online tracking and positioning of a pig in a mountainous natural gas pipeline according to claim 1 is characterized in that: In the S5, there is a pressure sensor and a flow sensor upstream and downstream of the valve chamber. When the pipe cleaner approaches the pressure sensors at both ends of the valve, the pressure upstream of the valve chamber will change from a stable state to an increased state, and the pressure downstream of the valve chamber will first decrease and then increase. When the pipe cleaner passes completely, the pressure upstream and downstream of the valve chamber returns to a stable state, but the pressure will be higher than the pressure when the pipe cleaner does not pass. When the pipe cleaner approaches the flow sensors at both ends of the valve chamber, the flow rate decreases. When the pipe cleaner passes completely, the flow rate will gradually return to a stable state. When it is monitored that the pressure upstream of the valve chamber increases and the flow rate upstream of the valve chamber decreases, it indicates that the pipe cleaner has passed through the valve chamber.

3. The method for online tracking and positioning of a pig in a mountainous natural gas pipeline according to claim 1 is characterized in that: The continuity equation and momentum equation of natural gas hydrate slurry are as follows: Continuity equation of natural gas hydrate slurry: In the formula, ρ h Indicates the density of hydrate slurry, kg / m 3 ; u represents the flow velocity of hydrate slurry, m / s; Momentum equation for natural gas hydrate slurry: In the formula, ρ h Indicates the density of hydrate slurry, kg / m 3 ; u represents the flow velocity of hydrate slurry, m / s; P represents the pressure of hydrate slurry in the pipeline, Pa; β represents the inclination angle of the pipeline; F represents the friction between hydrate slurry and the pipe wall, which generally needs to be obtained through the study of the mechanical properties of natural gas hydrate slurry, N.

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