基于次声波的钻井返出液液面检测系统设计

Design of Drilling Return Fluid Level Detection System Based on Infrasound Wave

针对传统声波液面测量装置存在的精度较低以及抗干扰能力差等问题,设计了一款基于次声波的钻井返出液液面检测系统。该系统以声波检测原理为基础,将检测系统进行模块化设计,利用高压气体作为声源产生次声波信号,设计与信号相匹配的信号调理电路,结合数据采集卡实现声波信号的采集。为了消除井下的噪声干扰,利用随机共振滤波算法对采集的信号进行预处理,降低信号噪声。根据钻杆的接箍回波和液面反射波信号的特点,采用快速傅里叶变换的方法,实现了动液面深度的计算。根据现场测试结果,返出液液面回波信号经过随机共振滤波算法处理后,信噪比约为10 dB,系统测量的数据与实际结果符合度较高,能够较好地满足钻录一体化监测系统对动液面数据的需求。研究结果对石油录井工程具有一定的实用价值。

To solve the problems such as low accuracy and poor anti-interference ability of traditional acoustic level instrument,an infrasound wave based drilling return fluid level detection system was designed.In the system,based on the principle of acoustic detection,the detection system is designed in a modular manner,high pressure gas is used as the sound source to generate infrasound wave signals,a signal conditioning circuit matched with the signal is designed,and a data acquisition card is combined to achieve the acquisition of acoustic signals.To eliminate downhole noise interference,the stochastic resonance filtering algorithm was used to preprocess the collected signals and reduce the signal noise.Based on the signal characteristics of the echo wave of drill pipe coupling and the reflected wave of fluid level,the fast Fourier transform method was used to calculate the depth of the dynamic fluid level.Field test results show that after processing of return fluid level echo signals by stochastic resonance filtering algorithm,the signal to noise ratio is about 10 dB;the measured data of the system is in good agreement with the actual results,and can better meet the requirements of the drilling and logging integrated monitoring system for dynamic fluid level data.The research results have certain practical value for mud logging engineering of oilfields.