Research Of Ultrasonic Wall-thickness Measure Technology For CNG Storage Well

CNG(compressed natural gas)storage wells are widely used as natural gas storage devices in China,which need to be detected periodically to ensure safety.While CNG storage wells are in service,it is one of the major failure modes of them that the wellbores becoming thinner and even broken due to both inside and outside corrosion phenomenon of wellbore walls,and this can cause huge economic losses and security accidents.Based on the phenomenon that current devices detecting wall thickness of CNG storage wells are often of relatively large volume,high cost and low mobile ability in the wells,this paper researches on an ultrasonic wall-thickness measure system for CNG storage wells by water immersion method.This system includes an ultrasonic thickness measure device and ultrasonic data analysis software.The ultrasonic thickness measure device collects the wall thickness information through the ultrasonic probes and embedded system inside it,and then transmits it to the ultrasonic data analysis software to analyze.The main contents of this paper are as follows:(1)According to the actual situation of CNG storage well wall-thickness measurement and relative national detection requirements,this paper puts forward the framework of the ultrasonic wall-thickness measure system for CNG storage wells through water immersion method,based on the analysis of advantages and disadvantages of thickness measure devices both at home and abroad.This provides general guide for the design of the ultrasonic wall-thickness measure system.(2)The design requirement of every part of the ultrasonic wall-thickness measure system is proposed with the application of water immersion ultrasonic thickness measure method.Then this paper conducted detailed design of the embedded system,mechanical system,lifting system of the ultrasonic thickness measure device and the ultrasonic data analysis software and finished an ultrasonic wall-thickness measure system that is portable,efficient and stable.(3)Both laboratory and field experiments are conducted to test whether the ultrasonic wall-thickness measure system can meet the accuracy standard and to find problems in the actual situation.Through analyzing and solving the problems,the ultrasonic wall-thickness measure system can already be applied practically at present.