The Research On Flaw Detection Of Gas Storage Wells Based On Ultrasonic Phased Array Detection

Ultrasonic non-destructive testing technology is widely used in wellbore detection of gas storage wells due to its intuitive detection results,strong penetrating ability and high reliability.However,the conventional ultrasonic gas storage well wall flaw detection system cannot achieve higher precision defect detection due to the limitation of single-element probe.In order to realize high-precision detection of well wall defects in gas storage wells,a design scheme of 64-element convex phased array gas storage wellbore flaw detection system is proposed.The influence factors of the sound field characteristics of the convex phased array are studied by sound field simulation,and the convex phased array probe is designed based on the study of the sound field characteristics of the convex phased array.The main work and achievements are as follows:1.The basic theory of ultrasonic sound field is elaborated,including ultrasonic propagation characteristics,sound field directivity and resolution.The principle of phased array detection is studied,including emission beam deflection,aggregation and reception delay synthesis.Finally,phased array imaging and common scanning methods are introduced.2.Designing a gas storage well wall flaw detection system based on a 64-array convex phased array probe,according to the basic radiation theory of sound field,a convex phased array probe model is established.The effects of convex radius,element size and array element spacing on the focused sound field of convex phased array are studied by sound field simulation.Based on the research of convex phased array focusing sound field,the convex phased array is designed to meet the flaw detection requirements of gas storage wells.3.Based on the convex phased array design,the beam focusing and synthesizing rules are calculated,including the delay pulse parameters and the received echo de-delay parameters of each array element.The linear sweeping method is used to detect the wellbore of the gas storage well,and the defect detection effect of the convex phased array is analyzed through simulation experiments.4.Design and Implementation of FPGA for Ultrasonic Echo Data Post Processing,including the design of the received sound beam synthesis module,the sliding window to baseline module and the sampling factor module,and the function of each module is verified by Modelsim simulation.