Research Of Oil Pipeline Leakage Detection Method Based On Wavelet Analysis

The paper introduces some pipeline leak detection technologies in our country and others, studies the meliorated Negative Pressure Wave detection technology and the correlative theory, and designs a set of project base on the oil pipeline of DaQing oil field to test the pipeline's leak efficiently includes in hardware and software scheme, particular introduces as follows:1. Two crucial technologies in instantaneous negative pressure wave method are analyzed in this dissertation, then a means is presented which can eliminate the dynamic response time diversity between pressure sensors in the beginning and end of the pipeline, by adopting Global Position System( GPS) to unify the system time between data collecting systems in two ends.2. Analysis is done on the change rules of liquid' s temperature along with the pipeline's distance .The paper points out the defects of the const pressure wave velocity method and do some improvements on it rebuilding the expressions of the pressure wave velocity in accordance with the Simpson's rule. Combining with the time difference value of the pressure wave getting to both ends of the pipeline, adopts half divide search method to search the leak site of the pipeline.3. The relation between wavelet transform and signal singularity and the method of testing signal singularity employing wavelet transform are discussed in the paper, and gets different wavelet transform trends of signals with different characters. The paper makes use of multi-scale wavelet transform to detect the arriving time of the pressure wave to the both ends of the pipeline. The method could detect the break point of the signal, and could decrease the error bringing by the existing of impulse yawp.4. In the process of the exclusion of the disturbing pressure wave, double-ended sensors are used. The difference of the time in which two sensors receive the disturbing pressure wave and the pressure wave that is caused by leak is used to differentiate the pressure wave which is caused by working condition and leaking accident, which is in order to judge the leak .5. A real-time supervising and localization system for crude oil concentrated transport pipeline are designed with DELPHI and MATLAB technology. The result proves that the method on oil pipeline leakage detection based on wavelet analysis can be used in reality and accurately can locate the leak point.