多路高精度相位检测技术研究

Investigation of Multi-channel High-precision Phase Detecting Technology

复电阻率相位检测技术是目前复电阻率测井技术发展的方向.实验研究表明,复电阻率的相位变化与岩心的饱和度有很好的线性关系,但变化范围只有1°～4°,因此要求相位检测的精度要低于1%.应用CPLD技术实现了微小相位信号的高精度检测,应用数字可编程器件实现了100MHz频率下的相位检测.详细介绍了检测系统的组成和测量方法,并给出了软件模拟和硬件测试结果.实验结果表明,4.5 kHz频率时测量系统能够达到相对误差0.8%的精度要求,能够满足复电阻率相位检测要求的精度.

The phase detecting is very important in complex resistivity well logging technology. The experimental results showed that the percent frequency effect of the phase changes linearly with the water saturation in the cores. Since the phase ranges from 1° to 4°, the detecting system should have a relative error which is lower than 1%. In this paper, a high-precision phase testing system for complex resistivity logging was introduced. The large-scale complex programmable logic device （CPLD） has been used in the low phase detecting. The system frequency is 100 MHz. The system components and detecting methods were described. The results of simulation and practical detection show that the system has a relative error of 0. 8% at 4. 5 kHz which can be used in practice.