基于声学的油井液面高度测量仪器研制 毕业设计 .doc

CHANGSHA UNIVERSITY OF SCIENCE TECHNOLOGY 毕业设计（论文） 题目：基于声学的油井液面高度测量仪器研制 基于声学的油井液面高度的测量仪器研制 摘要 在油井的开采过程当中，需要对油井的温度、压力、液面高度等一系列参数进行测量，监控整个油井的开采过程，同时为下一步的工作提供相关的指导，其中油井的液面高度是一个非常重要的参数。它能够真实的反应地质储量、优化生产，减少抽汲车的空返、提高采油泵的泵效并提高其的使用寿命。 本设计中的油井液面高度测量主要通过渡越时间法，即在井口利用爆炸声源产生的一大功率声波信号，利用声波信号在油井环套中传播遇到接管管面和液面反射的原理，再通过微音器接收反射回来的信号。然后通过对回波信号的曲线进行分析，得到液面波反射回井口的时间，最后通过声波在空气中的传播速度计算出油井的液面高度。 在对油井液面高度测量的返回曲线进行分析的过程当中，根据在声波法测油井液面高度的过程当中声波频率的研究和噪声信号产生的原因，设计低通数字滤波器和利用谱相相减法对液面反射波进行处理，达到将具有高频特性的油井接箍波和噪声波信号去除掉的目的。然后将短时幅值及过零率函数用于液面反射波的识别，得到液面反射波的具体位置，从而得到从发射声波到微音器接收到液面反射声波的时间。最后通过对接箍反射波利用快速傅里叶变换计算出声波在油套环空气中传播的速度，从而计算出油井液面的高度。 关键词：声波；数字滤波器；短时幅值及过零率函数；傅里叶变换 ABSTRACT When exploration wells, we need to measure temperature, pressure, liquid level and a series of parameters on the wells and monitoring wells as a whole mining process, providing relevant guidance for the next step at the same time. The well fluid level is a very important parameter. It can real reaction geological reserves 、optimize production reduce swabbing car empty return and improve the efficiency of mining pump and increase of its service life. The design of the well liquid level is measured mainly by the transit time method, at the well head using a high-power pulse signals generated by the explosion source, the use of acoustic signals encountered in principle to take over the tube surface and the surface reflection spread well ring, and then receiving the signal reflected back through the microphone. Curve of the echo signal to obtain the surface wave is reflected back into the wellhead, and finally through the propagation velocity of sound waves in air to calculate the liquid level of the wells. In return curve analysis on the well surface height measurements, According to the acoustic frequency and noise signals generated in the process of the height of the acoustic method to measure the well surface, Design low-pass digital filter and spectral subtraction processing, to achieve