连通井磁场测距系统中信号处理与传输的研究

Research on Signal Processing and Transmission for Connected Well Magnetic Field Ranging System

摘要:

为了克服连通井中高温、高压、强震动等恶劣环境对磁场测距系统的干扰,减小测量短节与钻头的耦合效应的影响、提高信号传输效率,实现连通井磁场测距系统的精确定位功能;文章在硬件上从传感器与AD转换芯片选型到信号调理电路等进行匹配设计；在软件上对比分析FIR和IIR滤波效果并根据IIR精度低的缺点,提出一种定点数与浮点替换运算、混合编程和优化程序结构的IIR优化设计方案；在上下井信号传输中采用曼切斯特编码通信,降低干扰、提高传输速率;仿真表明改进的IIR相对原IIR数据精度提高了两个百分点,相对FIR滤波时间提高了19倍;在误差允许范围内,系统采用该方法可以克服干扰得到精确的测量结果,满足设计要求。

Abstract:

In order to eliminate the interference to Magnetic Field Ranging System from harsh conditions such as high temperature, high pressure, and strong vibration and so on, reduce the coupling effect between gauging nipple and drill, increase efficiency of signal transmission, so as to achieve accurate positioning function of Magnetic Field Ranging System in connected wells, t he article adopt matching design from the selection of sensor(s) and AD conversion chip to the signal conditioning circuit in the aspects of hardware, while in the aspects of software, compares and analyzes the filtering effect of FIR and IIR and aims at the disadvantage of low accuracy of IIR, then a design has been proposed which adopts substitution operation of fixed-point number and floating-point number, in hybrid programming and with Optimize the program structure. In addition, the Manchester coding has been applied in the under well signal transmission for reduce the interference and improve the transmission rate. The simulation shows that, the improved version of IIR filter increases by two percent in data accuracy when compared with the original one, its speed is 20 times of the FIR. In the range of allowable error, adopts the method,the system can overcome the interference to get accurate measurement result, meet the design requirements.