一种用于随钻核磁共振测井的钻柱运动监测电路

A Drill String Motion Monitoring Circuit for Nuclear Magnetic Resonance Logging While Drilling

在随钻核磁共振测井过程中,钻井过程产生的横向振动会对测井结果产生严重干扰,结合测井过程中仪器的振动位移对测井回波数据进行分析,可有效提高测井结果的准确性。设计了一种使用压电式加速度计的运动监测电路,实时监测测井仪器的横向振动。该电路设计了恒流源供电电路、加速度信号处理电路、多路模数转换电路和基于DSP+FPGA结构的时序控制与信号处理电路,并在155℃的环境下测试了关键电路的性能。振动试验结果表明:本电路在强振动环境下具有良好的采集性能,加速度测量偏差在0.3g以下,满足随钻测井仪器振动测量的要求。

In process of nuclear magnetic resonance logging while drilling, the lateral vibration generated in the drilling process will seriously interfere with the logging results.The accuracy of logging results can be effectively improved by analyzing the logging echo data combined with the vibration displacement of the instrument in the logging process.A motion monitoring circuit which can work in high temperature and strong vibration environment is designed by using piezoelectric accelerometer to monitor the transverse vibration of logging tool in real time.The circuit designs constant current source power supply circuit, acceleration signal processing circuit, multi-channel analog-to-digital conversion circuit and timing control and signal processing circuit based on DSP+FPGA.The performance of the key circuit is tested at 155 ℃.The vibration test results show that this circuit has good acquisition performance in strong vibration environment, and the acceleration measurement deviation is less than 0.3g,which meets the requirements of vibration measurement of logging while drilling instruments.