套管井中仪器偏心对超声回波的影响

The Influences of Tool Eccentricity in a Casing Well on Ultrasonic Echo

根据声波在介质中的传播理论和换能器的声学特性，对在套管井中仪器处于不同偏心情况下的超声回波进行了模拟，研究了偏心对超声回波的影响，并进行了实验验证．数字模拟和实验结果表明：仪器偏心不仅会引起回波信号幅度的变化，而且会导致频谱的改变．当偏心大于４ｍｍ时，对回波的影响比较明显；为了保证套管井测井资料的可靠性，仪器偏心应小于３．５ｍｍ．

According to the theory of sonic propagation in medium and the acoustic characteristics of the ultrasonic transducer, the ultrasonic echoes are simulated under various eccentricities of the tool in a casing well. The influences of tool eccentricity on the echoes are investigated and the experimental verification is carried out. Simulation and experimental results show that the tool eccentricity can not only affect the amplitude, but also the spectrum of the echo. The effects are serious when the eccentricity is larger than 4mm. It is concluded that the eccentricity should be smaller than 3.5mm to guarantee the reliability of the logging data.