高精度钻孔温度仪及井下集成技术研究

Research on High-Precision Borehole Thermometer and Downhole Integration Technology

为了克服连接导线的热电偶效应和测量电路零点漂移的影响,本文基于DFT变换的信号提取技术,在铂电阻测温电桥中应用交流驱动,设计了高精度钻孔温度仪,以及钻孔温度观测的集成方案和实验方案.实验室测试表明,≥0.5 mHz频带的温度测量噪声水平优于0.03 mK/Hz^(1/2).应用于中国地震科学实验场长期观测结果显示,该高精度钻孔温度仪运行稳定,数据完整,为实验场地震模型的检验和地震前兆异常的判断提供了观测手段和数据支撑.

In order to overcome the thermocouple effect of the connecting wire and the influence of the zero drift of the measurement circuit,a high-precision borehole thermometer,as well as the borehole temperature observational integration and experimental scheme were designed based on the signal extraction technology of DFT transformation.The AC drive was applied into the platinum resistance thermometer bridge.Laboratory tests show that the power spectral density of temperature noise is less than 0.03 mK/Hz^(1/2)in the frequency band≥0.5 mHz.Long-term observations of the China seismic experimental site show that the high-precision borehole thermometer runs stably and has complete data,so as to provide observation means and data support for the experimental site seismic model verification and earthquake precursory anomalies.