基于管柱声场模型的油井动液面检测新方法

针对传统回波法测油井动液面存在回波信号弱、干扰噪音大和液面波辨识难等问题，提出一种基于管柱声场模型的油井动液面检测方法。受管乐器声乐频率可反映乐管长度的启发，利用管道声学理论对典型的管柱结构进行分析，借助管柱的声场特性和管内空气柱的共振原理，建立油井动液面深度与管内声场固有频率的关系，再通过快速傅立叶变换测定管内声场的固有频率，从而获得管内动液面深度。实验结果表明，提出的新方法验证了管柱空气共振频率和动液面深度的关系，能较精确地得到管内液面深度，相对误差在2% 以内，为精确检测油井动液面深度提供了一种新途径。

A New Method for Oil Well Dynamic Fluid Level Detection Based on the Column Sound Field Model

It is important to measure the depth of dynamic liquid level of oil well in order to set reasonable oil extractiontechnology. In this paper，we proposed a detection method of oil well dynamic fluid level based on the sound field model ofthe column，in order to solve the problem of weak echo signal，large noise disturbance and difficult identification of liquidlevel wave in the traditional echo method. In this method，the typical string structure can be analyzed with the pipeline acoustictheory. Moreover，the relationship between the well dynamic fluid level depth and the natural frequency of the tube sound fieldis established，according to the sound field characteristic of the column and resonance theory of tube air column，inspired by thefact that the vocal frequency of wind instrument can reflect the acoustic pipe length. Then we measured the natural frequencyof the sound field in tube by Fast Fourier Transform（FFT），and liquid level depth of tube will be obtained. The experimentalresults confirm the relationships between the string air resonance frequency and dynamic liquid level，and show that the tubeliquid level depth is more accurate within 2% relative error by using this method which provides a new way for the accuratedetection of the well dynamic fluid level depth.