Study On Identification Of Pipe Damage Based On Seismic Inversion Technology

As one of the five major ways of transportation,pipeline transportation plays a much more important role in the economy construction and national defense industry. If the pipeline leakage happened, much substance would be lost and the environment would be polluted. It affects normal production and people's everyday life seriously. Therefore, a safe and efficient non-destructive inspection method has become an urgent demand in today's society.Guided wave technique has some good properties, such as high efficiency of detecting, less time needed and it can be used to inspect the whole wall thickness of pipeline, so it has been widely applied in non-destructive structure inspection. The aim of this thesis is carrying out some basic theoretical research and experimental studies on the guided wave technology for the damage detection of pipeline. Seismic deconvolution method is selected for signal processing. This method which can improve the resolution of signals is an important part of seismic inversion technology and is one of the most important methods for seismic data processing. Guided wave technology and seismic deconvolution will be combined together to achieve the positioning of pipe damage.This thesis consists of two parts. The first part includes the studies on the simulations of traditional seismic deconvolution and the analysis of characteristics of each algorithm. These traditional seismic deconvolution methods are least squares deconvolution which is the most basic deconvolution method, predction deconvolution which is widely used and minimum entropy deconvolution which is based on high order statistics, repectively. The first two mehods have requirement on the phase of seismic wavelet, and the last one has no requirement. In the second part, integral pipe and defective pipe are detected respectively using guided wave technology and the measured signals are processed by seismic deconvolution method to improve the resolution. In the experiments, different guided wave signals are measured by changing the position of the sensor. In the integral pipe experiment, propagation characteristics of each guided wave mode are studied. In the defective pipe experiment, the detection capability of each guided wave mode is analyzed and the ultimate purpose of precise positioning of pipe damage is also realized.