随钻电磁波电阻率温度修正方法研究

随钻电磁波电阻率测量是实时获取地层电阻率并进行地质导向钻井的主流技术。为了分析温度对随钻电磁波电阻率测量精度的影响,针对自主研发的MRC随钻电磁波电阻率测井仪器,采用吊零刻度与温度标定相结合的方法,通过无磁高温测试装置对仪器刻度标定,对不同温度下的测量结果进行了分段拟合修正。研究结果表明:随钻电磁波电阻率测井仪器测量误差通常包括零点漂移误差和温度漂移误差,修正之后的MRC随钻电磁波电阻率测井仪器在7.5~110.0℃温度范围内,相位差测量误差不超过0.005°,幅度比测量误差不超过0.01 dB,能够有效分辨薄层,准确测量大动态范围的电阻率变化。所得结果可为随钻电磁波电阻率测量方法的优化提供参考。

Research on Temperature Modification Method for Electromagnetic Resistivity LWD

Electromagnetic resistivity measurement while drilling is the mainstream technology for real-time formation resistivity measurement and geosteering drilling.In order to analyze the influence of temperature on the measurement accuracy of the electromagnetic resistivity measurement while drilling,air hang calibration and temperature calibration was combined to investigate the independently developed MRC electromagnetic resistivity LWD tool.The instrument scale was calibrated by using a non-magnetic high temperature test device and the segmented fitting correction was performed on the measurement results at different temperatures to reduce system errors and dynamic temperature drift errors simultaneously.The research results show that the measurement error of the electromagnetic resistivity LWD tool usually includes zero drift error and temperature drift error.In the temperature range of 7.5~110.0℃,the corrected MRC electromagnetic resistivity LWD tool has the measurement error of phase difference less than 0.005°and the measurement error of amplitude ratio lower than 0.01 dB.Therefore,it can effectively distinguish thin layers and accurately measure resistivity changes with large dynamic range.