Study On Oil-Transportation Pipeline Damage Prevention Monitoring And Its Lacating

Pipe, one of the five primary transportation tools, has its own unique advantages in the transportation of liquid, gas and serosity, playing an irreplaceable role especially in petroleum, chemical industry, gas and water supply industries. In order to ensure the normal running of pipeline transportation and prevent from manmade damage incidents, it is very important to carry out such researches as active protecting and accurate positioning. The tutorial gives a general introduction to the research of oil-transportation pipeline damage prevention monitoring and its locating technology, primarily for the following :(1) Studied the characteristics of the sound field and transmission in different conditions, the results show that it is more favorable to transmit acoustic signal by using fluild medium than pipe-wall, low frequency acoustic signal can transmit a long distance in the medium of pipes.(2) Acoustic pressure sensor designed by electret capacitance can withstand fluid static pressure and detect accurately transient pressure signals. The sensor can prevent actively from manmade damage incidents, it achieved good results through experiments in collection stations of Dagang oil field.(3) Analysed pretreatment methods of the original acoustic signals,including:filtering, start and end point detection and sub-frame; LPCC (Linear Prediction Cepstrum Coefficient) which represents accurately all the acoustic signal information was selected as the acoustic signal characteristics parameters, and can be effectively extracted using Durbin algorithm; HMM(Hidden Markov Models) parameters were calculated with Baum-Welch training algorithm, Viterbi decoding realized the search of best transfer route and achieved the corresponding output probability. The acoustic recognition models HMM was built to identify damage types effectively, and simulated with MATLAB.(4) Completed hardware design of the system,which can realize the function of anti-theft monitoring.RTU(Remote Terminal Unit) may receive time and send feature coding information by using double serial ports of high-speed MCU; Acoustic recognition module can identify damage types effectively; In order to capture time more accurately which acoustic signals arrived at the two points, GPS(Global Position System) was used to uniform system time; DTU can exchange information real-timely with the data service center using GPRS(General Packet Radio Service) wireless networks and Internet.(5) Debugged monitoring system and achieved good results.