Submarine pipeline length real-time measurement system and method for monitoring suspended span and landslide by using same

Abstract

The invention discloses a submarine pipeline length real-time measurement system and a method for monitoring suspended span and landslide by using the same, a hammering device for hammering a pipeline is arranged at a fixed measurement point, a plurality of sensors are installed at intervals along the length direction of the pipeline, each sensor is used as a detection point, and the detection point is used for detecting the length of the submarine pipeline. The sensor is used for detecting a vibration wave signal generated after the pipeline is hammered and has a timing function; each sensor respectively records the time from the beginning of hammering to the receiving of the vibration wave, then calculates the distance value between each detection point of the pipeline and a fixed detection point according to the known propagation speed of the vibration wave in the submarine pipeline, and calculates the change condition of the constraint force of the along-way soil body of the pipeline according to the change condition of the distance value. And the suspended span and burying conditions of the pipeline are identified.

Description

Technical Field

[0001] The invention belongs to the technical field of submarine pipeline detection, and in particular relates to a submarine pipeline length real-time measurement system and a method for monitoring overhangs and landslides using the system. Background Art

[0002] As the development of offshore oil and gas resources advances into the deep sea, the amount of submarine pipelines laid is increasing. The environment in which submarine pipelines are located is very complex, with the effects of seawater confining pressure, water buoyancy, ocean currents and submarine landslides, and the boundary conditions of submarine pipelines are also relatively complex and changeable. Under such conditions, once submarine pipelines are suspended or buried, the hidden dangers they bring are huge.

[0003] The stability and safety of pipelines are closely related to the restraint force of the seabed soil on them. During the pipeline design phase, the corresponding stability design will be carried out according to the geological conditions of the seabed along the pipeline. However, pipelines often serve for a long time. During the entire service life, on the one hand, the existence of the pipeline structure will change the flow field of the submarine current, causing the seabed at the bottom of the pipeline to be eroded to form a suspended span. The suspended span section of the pipeline is prone to vortex-induced vibration, which may cause damage to the pipeline structure; on the other hand, within the entire route of the pipeline, the soft soil on the seabed may also cause landslides, causing part of the pipe section to be buried, which is not conducive to the stability of the pipeline, and then causing the pipeline to become unstable and damaged. Therefore, the suspended span and burial of the seabed along the pipeline are important threats to pipeline safety.

[0004] At present, there are relatively mature pipeline monitoring methods, which can be roughly divided into two types: engineering geophysical exploration and diving exploration. The engineering geophysical exploration method mainly uses sonar propagation for measurement, but these two methods require high manpower and material resources, and it is difficult to observe the suspended spans of some pipelines or those that are blocked. It is almost impossible to manually explore all pipelines. For the initial smaller suspended spans and smaller landslide burials, it is difficult to accurately detect them due to the influence of pipeline structure and seabed topography. In addition, the cost of detection technologies such as sonar is high, and the operation time and frequency of the detection ship at sea are affected by conditions such as wind and waves, making it difficult to achieve high-frequency and real-time monitoring. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and provide a real-time measurement system for the length of a submarine pipeline and a method for monitoring overhangs and landslides using the system. The present invention measures the distance between each detection sensor on the pipeline and a fixed monitoring point on the seabed, and calculates the change in soil constraint force along the pipeline according to the change in the distance value, thereby identifying the overhang and buried conditions of the pipeline.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A real-time measurement system for the length of a submarine pipeline comprises a fixed measuring point, which is fixed on the seabed and is provided with a hammering device for hammering the pipeline; a plurality of detection sensors are installed at intervals on the pipe wall of the pipeline along the length direction of the pipeline, each detection sensor serves as a detection point, and the detection sensor is used to detect a vibration wave signal generated after hammering the pipeline, and has a timing function; the hammering device and all the detection sensors are connected to a control and information processing system through a signal transmission line, and the control and information processing system is used to control the hammering device and each detection sensor to work, and to receive data from each detection sensor and analyze and process the data.

[0008] The working method of the above-mentioned submarine pipeline length real-time measurement system comprises the following steps:

[0009] Step 1: The control and information processing system sends a start measurement command to the hammer device at the fixed measuring point and all the detection sensors through the signal transmission line; the hammer device starts to hammer the pipeline after receiving the start measurement command; the detection sensor starts timing after receiving the start measurement command;

[0010] Step 2: The vibration wave signal generated after the pipeline is hammered is detected in real time by each detection sensor. When the detection sensor detects the vibration wave signal, it stops timing itself. The time recorded at this time represents the transmission time of the vibration wave from the fixed measuring point to the current detection sensor detection point. The timing time data is fed back to the control and information processing system through the signal transmission line;

[0011] Step 3: The control and information processing system calculates the distance between each detection point on the pipeline and the fixed measurement point in this measurement based on the timing data fed back by each detection sensor and the known propagation speed of the vibration wave in the submarine pipeline.

[0012] In the above technical solution, the action time from when the hammer device receives the start measurement command to when the hammer head contacts the pipe is determined. When calculating the distance, the timing time fed back by each detection sensor is first subtracted from the action time, and then multiplied by the propagation speed to calculate the distance value.

[0013] A method for monitoring overspan and landslide of submarine pipelines using the above submarine pipeline length real-time measurement system: performing multiple measurement tasks on the pipeline according to a set monitoring cycle or according to actual needs, thereby obtaining historical change data of the distance value of each detection point of the pipeline from a fixed measurement point, and further inferring whether the submarine pipeline has overspan or buried, the time when the overspan and burial occurred, and identifying the position and axial range of the overspan and burial based on these historical change data.

[0014] In the above technical solution, a digital twin model of a submarine pipeline is established. The normal pipe flow data of each inspection point of the submarine pipeline is predicted in advance based on the digital twin model, and the pipeline is measured. The predicted pipe flow is interpolated into the measured distance value of each inspection point for correction, so as to more accurately analyze and judge the overhang and burial conditions of the submarine pipeline.

[0015] The present invention has the following advantages and beneficial effects:

[0016] Compared with detection systems such as sonar that rely on ships on the sea surface, (1) the measurement system of the present invention is located on the seabed surface and is not affected by factors such as storm surges, so it can achieve all-weather, real-time measurement; (2) the pipeline sensors, fixed measuring points and other equipment of the measurement system of the present invention can be installed together during the pipeline installation process, and the cost of a single measurement is extremely low, with less overall investment; (3) The span formed by pipeline scouring is formed over time, and the scouring span is small in size in the early stage and is located below the pipeline. The detection signals of detection methods such as sonar that rely on sea surface ships are easily obscured by the pipeline structure, making it difficult to detect early overhangs. The method for detecting overhangs in the present invention is to analyze the soil constraint along the pipeline. Even a small overhang will cause the loss of soil constraint in the local pipeline, which will then be reflected in the change of pipe flow. Therefore, the present invention can make up for the problem that the previous technology is difficult to detect early overhangs; (4) The present invention establishes a digital twin model of the submarine pipeline, predicts the normal pipe flow data of each detection point of the submarine pipeline in advance based on the digital twin model, and conducts actual measurements on the pipeline, interpolates the predicted pipe flow into the measured distance value of each detection point, and performs correction, so as to more accurately analyze and judge the overhang and burial conditions of the submarine pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the real-time measurement system of submarine pipeline length of the present invention.

[0018] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0020] Embodiment 1

[0021] A real-time measurement system for submarine pipeline length, see attached Figure 1For the submarine pipeline AB to be monitored, a fixed measuring point C is set near the end B of the pipeline. The fixed measuring point C is fixed on the seabed to keep its position relative to the earth unchanged. A hammer device is set at the fixed measuring point C to hammer the pipeline so that the pipeline generates vibration waves that propagate along the pipeline; and multiple detection sensors D are installed on the pipe wall along the length direction of the pipeline at intervals. 1 , D 2 , D 3 ..., each detection sensor serves as a detection point, the detection sensor is used to detect the vibration wave signal generated after hammering the pipeline, and has a timing function; the hammering device and all the detection sensors are connected to the control and information processing system through a signal transmission line, the control and information processing system is used to control the hammering device and each detection sensor to work, and to receive data from each detection sensor and analyze and process the data.

[0022] The working method of the above-mentioned submarine pipeline length real-time measurement system is described in detail below, including the following steps:

[0023] Step 1: The control and information processing system transmits the signal to the hammer device at the fixed measuring point C and all the detection sensors D through the signal transmission line. 1 , D 2 , D 3 ...send a start measurement command; after receiving the start measurement command, the hammering device starts and hammers the pipeline; after receiving the start measurement command, the detection sensor starts timing (the time for the electrical signal to propagate is negligible, and it is assumed that all detection sensors and hammering devices receive the command at the same time).

[0024] Step 2: After the hammering occurs, the vibration wave signal propagates along the pipeline. The vibration wave signal generated after the hammering of the pipeline is detected in real time by each detection sensor. When the detection sensor detects the vibration wave signal, it stops its own timing. At this time, the recorded time represents the transmission time of the vibration wave from the fixed measuring point C to the current detection sensor detection point position. The timing time data is fed back to the control and information processing system through the signal transmission line.

[0025] Step 3: The control and information processing system can calculate the detection sensor D of each detection point of the pipeline based on the timing data fed back by each detection sensor and the known propagation speed of the vibration wave in the submarine pipeline. 1 , D 2 , D 3 ...In this measurement, the distance value X from the fixed measuring point C is 1 , X 2 , X 3……. It should be noted that after the hammer device receives the command to start measuring, there will be a specific action time from the start of the hammer device to the hammer head contacting the pipe, that is, there will be a specific delay time. Therefore, when calculating the distance, it is necessary to first subtract the specific delay time from the timing time fed back by each detection sensor, and then multiply it by the propagation speed to calculate the distance value.

[0026] Embodiment 2

[0027] Furthermore, based on the technical solution of the first embodiment, multiple measurement tasks are performed on the pipeline according to the set monitoring cycle or according to actual needs, so as to obtain the historical change data of the distance value between each detection point of the pipeline and the fixed measuring point C. Based on these historical change data, it is further inferred whether the submarine pipeline has been suspended or buried, and the time when the suspended or buried occurred, and the position and axial range of the suspended or buried can be identified.

[0028] For example: This time the detection sensor D 1 The measurement distance X 11 Equal to the last measured distance X 1 Or at the last measurement of distance X 1 If the CD 1 There is no overhang or burial in the pipe section; when the current detection sensor D 2 The measurement distance X 22 Less than the last measured distance X 2 Or less than the last measured distance X 2 The lower limit of the normal deviation range is set, then D 1 D 2 Landslide buried in the pipe section, the landslide occurred in the interval between the last measurement and this measurement, the axial range of the landslide body can be compared with X 22 With X 2 The larger the difference, the larger the axial range of the landslide, and the smaller the difference, the smaller the axial range of the landslide. Further, the relationship between the difference and the axial range of the landslide can be established based on experimental data or measured data, and then the specific value of the axial range of the landslide can be quantitatively calculated based on the measured difference. 3 The measurement distance X 33 Greater than the last measured distance X 3 Or greater than the last measured distance X 3 The upper limit of the normal deviation range is set, then D 2 D 3 Scour overhangs appear in the pipe section. The overhangs appear in the interval between the last measurement and the current measurement. The axial range of the overhang can be determined by comparing the X 33 With X3 The larger the difference, the larger the axial range of the overhang, and the smaller the difference, the smaller the axial range of the overhang. Furthermore, a relationship between the difference and the axial range of the overhang can be established based on experimental data or measured data, and then the specific value of the axial range of the overhang can be quantitatively calculated based on the measured difference.

[0029] Embodiment 3

[0030] Furthermore, during the normal service of submarine pipelines, even if there is no overhang or burial, the lengths of various sections of the pipelines may change slightly (i.e., pipe slipping may occur). This is because submarine pipelines are affected by the geological conditions of the marine soil, the joints of the pipelines (the joints are prone to displacement and deformation), and the working load of the pipelines, which may cause pipe slipping.

[0031] Therefore, in order to more accurately analyze and determine the overhang and burial conditions of submarine pipelines, a digital twin model of the submarine pipeline can be established. The normal (i.e., no overhang and burial conditions) pipe flow data of each detection point of the submarine pipeline can be predicted in advance according to the digital twin model. The pipeline is measured using the technical solution of embodiment 1, and the predicted pipe flow is interpolated into the measured distance value of each detection point for correction. Then, the technical solution of embodiment 2 is used for analysis, so as to more accurately analyze and determine the overhang and burial conditions of the submarine pipeline.

[0032] The above description is only used to illustrate the present invention, and is not intended to limit the present invention to the structure and scope of use shown and described. Therefore, all corresponding modifications and equivalents made within the spirit and principle of the present invention belong to the patent scope applied for by the present invention.

Claims

1. A real-time measurement system for submarine pipeline length, characterized in that: The invention comprises a fixed measuring point, which is fixed on the seabed and is provided with a hammering device for hammering the pipeline; a plurality of detection sensors are installed on the pipe wall of the pipeline at intervals along the length direction of the pipeline, each detection sensor serves as a detection point, and the detection sensor is used to detect the vibration wave signal generated after hammering the pipeline, and has a timing function; the hammering device and all the detection sensors are connected to a control and information processing system through a signal transmission line, and the control and information processing system is used to control the operation of the hammering device and each detection sensor, as well as to receive data from each detection sensor and analyze and process the data.

2. The measuring method of the submarine pipeline length real-time measuring system according to claim 1 is characterized in that: The following steps are involved: Step 1: The control and information processing system sends a start measurement command to the hammer device at the fixed measuring point and all the detection sensors through the signal transmission line; the hammer device starts to hammer the pipeline after receiving the start measurement command; the detection sensor starts timing after receiving the start measurement command; Step 2: The vibration wave signal generated after the pipeline is hammered is detected in real time by each detection sensor. When the detection sensor detects the vibration wave signal, it stops timing itself. The time recorded at this time represents the transmission time of the vibration wave from the fixed measuring point to the current detection sensor detection point. The timing time data is fed back to the control and information processing system through the signal transmission line; Step 3: The control and information processing system calculates the distance between each detection point on the pipeline and the fixed measurement point in this measurement based on the timing data fed back by each detection sensor and the known propagation speed of the vibration wave in the submarine pipeline.

3. The measuring method of the submarine pipeline length real-time measuring system according to claim 2 is characterized by: Determine the action time from when the hammer device receives the start measurement command to when the hammer head touches the pipe. When calculating the distance, subtract the action time from the timing time fed back by each detection sensor, and then multiply it by the propagation speed to calculate the distance value.

4. A method for monitoring overhang and landslide of submarine pipelines, characterized in that: According to the set monitoring cycle, the measuring method of the submarine pipeline real-time length measurement system as claimed in claim 2 is used to perform multiple measurement tasks on the pipeline, so as to obtain the historical change data of the distance value of each detection point of the pipeline from the fixed measuring point, and based on these historical change data, it is further inferred whether the submarine pipeline has been overspanned or buried, the time when the overspan and burial occurred, and the position and axial range of the overspan and burial are identified.

5. The method for monitoring overhang and landslide of submarine pipeline according to claim 4 is characterized in that: A digital twin model of the submarine pipeline is established. The normal pipe flow data of each inspection point of the submarine pipeline is predicted in advance based on the digital twin model. The pipeline is measured and the predicted pipe flow is interpolated into the measured distance value of each inspection point for correction, so as to more accurately analyze and judge the free span and burial conditions of the submarine pipeline.

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