超声井下电视传感器的特性分析

Analysis of Properties of Ultrasonic Television Tools

分析了超声井下电视传感器的声学特性，针对国产ＤＢＨＴＶ超声测井仪给定的参数，计算了它的焦距、焦点直径、聚焦情况以及影响系统探测性能的因素；给出了接收声压随井径变化的公式，从公式中可以看出接收声压随井径的不同有很大的变化，进而得到为改善图象质量必须进行井径校正或偏心校正，推出的公式则提供了进行校正的依据．

Ultrasonic television tools is a downhole imaging instrument,which is widely used in field.In China,it has been successfully developed by Huabei Oilfield and Daqing Oilfield respectively.But its imaging quality is not satisfactory because the resolution of the sensor used here is lower and its performance is not analysed in detail.According to the authors analysis,it is held that eccentricity of the position of the instrument in borehole or irregularity of borehole is the main cause leading to image pollution.Taking DBHTV (Digital Borehole Television)of Huabei Oilfield as an example,authors analyse the properties of its sensor in detail,and derive the relationship between its focus,focal distance and the echo of ultrasonic pressure and borehole radius.It can be concluded that the propagation distance of ultrasonic pressure in borehole has a great effect on its echo.In order to eliminate the image pollution,work must start with the propagation distance.