Simulation Study Of Acoustic Wave Casing Damage Detection System

The phenomenon of casing breakage is common in oilfield development,which is mainly affected by factors such as geology and engineering.Traditional casing detection methods,such as mechanical well diameter detection,in-situ stress detection and electromagnetic detection technology,due to some disadvantages,their practical applications will be subject to many restrictions.Sonic casing detection technology has unique advantages in the practical application.In this paper,we present a design of YO-YO broadband transmit transducer and octagonal array receiver transducer which can be used for casing damage detection.The finite element software is used to analyze the performance of the transducer and their downhole communication.The casing damage was simulated to test the performance of the transducers.The main work of the paper is as follows:(1)A YO-YO broadband transmit transducer is proposed,which is composed of three sets of different rectangular piezoelectric tube longitudinal arrangement.Using COMSOL finite element software,the finite element model is established.The resonant frequency and vibration modes of the piezoelectric tubes are simulated respectively.The influence of the geometric parameters on the transmitter response level of the transducer is discussed by combining the longitudinal arrangement of each group of piezoelectric ceramics into YO-YO broadband transducers.Studies have shown that YO-YO structural transducers can make the transducers work in wider frequency bands.(2)The geometrical model of the octave array receiver transducer is established by using COMSOL in the acoustic-solid coupling module.The frequency domain characteristics of the receiver are analyzed.The results show that the transducer has high receiving sensitivity at 73 kHz.(3)by using the finite element method,the transmission of sound wave in the casing,casing and casing is simulated.The eight time domain acoustic signals received by the transducer can be used to analyze the change of signal amplitude,and the casing damage and damage can be judged by using the eight edge array.The study has some references for the transducer design and the casing detection in oil well.