Monitoring of Natural Gas Pipeline Leaks

2010 ◽  
Author(s):  
Dongliang Yu ◽  
Likun Wang ◽  
Bin Xu ◽  
Hongchao Wang ◽  
Min Xiong ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Negative Pressure ◽  
Pressure Measurement ◽  
Pressure Wave ◽  
Wavelet Packet ◽  
Wavelet Packet Decomposition ◽  
Wave Method ◽  
Decomposition Technique ◽  
Natural Gas Pipeline ◽  
Negative Pressure Wave

Pipe is a very important tool for long-distance transportation of nature gas. In the long-term running, there will be inevitably an appearance of a rupture, leak or damage usually caused by manmade event or by nature disaster. Leaks may generate dangerous clouds of gas escaping from the high-pressure pipe and produce serious incidences involving fire and explosion endangering the life and property safety of people in and around the area. Monitoring of natural gas pipeline leaks will timely find out and locate these dangerous occurrences and reduce loss. Within the leak monitoring, the core contents are the accurate location of leaks as well as the rapid identification of different signal sources reducing false alarm ratio. Once a leak occurs, the supersonic jet of escaping gas can generate a non-linear & chaotic negative pressure wave signal based on static pressure measurement and an acoustic signal based on dynamic pressure measurement [1]. By properly interpreting these two kinds of signals together, it is possible to detect and locate the leak along the pipe. However, useful signals usually mix in the powerful backdrop signals and noises. In order to resolve the problem, the wavelet packet decomposition technique [2] is used to reduce the noises and get the feature signals of negative pressure wave and acoustic wave. Furthermore, a lot of different condition regulating signals for instance compressor start-stop, valve adjusting and gas turbulence can interfere with the accurate identification of leaks and result in false alarm. It is quite required to classify these similar signals. Thus, BP neural network [3] is used to quickly recognize the different pressure fluctuation signals. Finally, an integrated system developed by LabView is introduced to timely monitor the operation condition and locate the leak. Field tests indicate this system using negative pressure wave method, acoustic wave method, wavelet packet decomposition technique as well as BP network has a good effect.

scholarly journals An Improved Negative Pressure Wave Method for Natural Gas Pipeline Leak Location Using FBG Based Strain Sensor and Wavelet Transform

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Qingmin Hou ◽  
Liang Ren ◽  
Wenling Jiao ◽  
Pinghua Zou ◽  
Gangbing Song
Keyword(s):  
Wavelet Transform ◽  
Natural Gas ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Strain Sensor ◽  
Wave Method ◽  
Positioning Accuracy ◽  
Natural Gas Pipeline ◽  
Leak Location ◽  
Negative Pressure Wave

Methods that more quickly locate leakages in natural gas pipelines are urgently required. In this paper, an improved negative pressure wave method based on FBG based strain sensors and wavelet analysis is proposed. This method takes into account the variation in the negative pressure wave propagation velocity and the gas velocity variation, uses the traditional leak location formula, and employs Compound Simpson and Dichotomy Searching for solving this formula. In addition, a FBG based strain sensor instead of a traditional pressure sensor was developed for detecting the negative pressure wave signal produced by leakage. Unlike traditional sensors, FBG sensors can be installed anywhere along the pipeline, thus leading to high positioning accuracy through more frequent installment of the sensors. Finally, a wavelet transform method was employed to locate the pressure drop points within the FBG signals. Experiment results show good positioning accuracy for natural gas pipeline leakage, using this new method.

Effect of rubber washers on leak location for assembled pressurized liquid pipeline based on negative pressure wave method

2018 ◽  
Vol 119 ◽  
pp. 181-190 ◽  
Author(s):  
Qiang Chen ◽  
Guodong Shen ◽  
JunCheng Jiang ◽  
Xu Diao ◽  
Zhirong Wang ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Pressure Wave ◽  
Wave Method ◽  
Leak Location ◽  
Negative Pressure Wave

Research on Leak Monitoring Technology for Product Oil Pipeline

2012 ◽  
Author(s):  
Dongliang Yu ◽  
Bin Xu ◽  
Likun Wang ◽  
Dongjie Tan ◽  
Hongchao Wang ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Mechanical Damage ◽  
Pipeline System ◽  
Accident Risk ◽  
Long Distance ◽  
Chemical Corrosion ◽  
Oil Pipeline ◽  
Negative Pressure Wave

As an important tool for the long-distance transportation of product oil, pipeline construction has being developed rapidly in recent years in the world. In the long-term running, leak will occur occasionally and seriously endanger the operation safety of the pipeline system, which may be caused by internal & external factors including pipe aging, mechanical damage, chemical corrosion, and natural disaster, etc. In order to timely find out and accurately locate the leakage, and reduce the economic loss and the accident risk, it is necessary to research into leak monitoring techniques and apply them in field. Compared with crude oil pipeline, due to multi-batch transportation, multi-distribution operation and frequent regulation, leak monitoring for product oil pipeline is much more difficult. Once leak occurs, the oil loss at the leakage point induces an oil pressure drop, causing negative pressure wave as well as acoustic wave. Through analyzing negative pressure wave signals and acoustic wave signals acquired by sensors, it can find out and locate the leakage. For interference signals like background noises in the product oil pipeline, wavelet packet decomposition technology is used to denoise the acquired negative pressure wave signals and acoustic wave signals, and extract the feature signals. Meanwhile, the signal velocity in product oil is calculated dynamically to improve the location accuracy. Field Tests indicate that the technology combining negative pressure wave and acoustic wave is accurate and reliable, and has good performance.

A Petroleum Pipelines Leakage Monitoring System

2004 ◽  
Author(s):  
Zhuang Li ◽  
Shijiu Jin ◽  
Likun Wang ◽  
Yan Zhou
Keyword(s):  
Monitoring System ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Wave Speed ◽  
Freezing Point ◽  
Oil Field ◽  
Wave Method ◽  
Negative Pressure Wave ◽  
Leakage Monitoring ◽  
Petroleum Company

The petroleum leakage has been a serious problem these years in China. The leakage, mostly caused by human destruction, lasting a short time with a large amount of loss, is not only an economic loss for the petroleum company, but environmental pollution, a public issue. Thus a monitoring system, which can identify the leakage and locate the leak point in real time, is required. One of the challenges is the sensitivity of the system. The system is expected to respond quickly to locate the point so that the security personnel can find and mend the orifice in time. Another challenge is the accuracy of the locating result. Because of the features of Chinese petroleum: high viscosity, high wax content and high freezing point, the sound wave speed in the oil is not a constant along the pipeline and the leak point calculated by the traditional negative pressure wave method are invalid. In this paper, a modified negative pressure wave method was put forward according to the variation of the wave speed. A wavelet-based algorithm applied to calculate the leak point gives fairly satisfied results. The data acquisition, signal processing and the structure of the pipeline leakage monitoring system (PLMS) were analyzed. The system has played a big role on the pipeline network in Shengli Oil Field and long pipelines of East China Oil Bureau.

Projective Noise Reduction Algorithm for Negative Pressure Wave Signal Processing

2008 ◽  
Author(s):  
Dongliang Yu ◽  
Laibin Zhang ◽  
Liang Wei ◽  
Zhaohui Wang
Keyword(s):  
Noise Reduction ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Random Noise ◽  
Background Signal ◽  
Long Distance ◽  
Noise Component ◽  
Wave Signal ◽  
Non Linear ◽  
Negative Pressure Wave

The appearance of a rupture, leak or damage in the long-distance oil & gas pipeline, which could cause a leak, usually generates a non-linear & chaotic negative pressure wave signal. By properly interpreting the negative pressure wave signature, it is possible to detect a leak along the pipeline. Most traditional noise reduction methods are established based on the linear system, which are not in line with the actual non-linear & chaotic situation. Therefore, the weak negative pressure wave signals, generated by small leaks, are often filtered out and cause false alarm and failure alarm. In order to resolve the problem, this paper uses the non-linear projective algorithm for noise reduction. First, the weak negative pressure wave signal series would be reconstructed using delay coordinates, in the high dimensional phase space, the background signal, the negative pressure wave signal and the noise signal are separated into different sub-spaces. Through the reconstruction of sub-spaces, the weak pressure wave signal can be isolated from the background signal as well as the random noise component reduced.

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