电成像测井图像微锯齿精细校正方法研究

Saw-tooth Effect Correction for Electric Imaging Logging Curves

电成像测井仪器在井下运动状态复杂,经过传统加速度校正方法处理后的电成像图像上仍会存在微锯齿现象,使得图像质量下降,增加了测井解释的多解性。对电成像测井图像微锯齿现象产生的原因进行分析,提出基于仪器相对运动速度分析的微锯齿图像精细校正方法。该方法通过各电极微电阻率曲线对比建立了反映仪器运动状态的相对速度变化曲线,在此基础上采用Kalman滤波模型进行图像真实深度预测与校正。应用实例表明,该方法有效降低了电成像测井图像处理过程中的微锯齿现象,提升了图像显示效果。

The motion state of electric imaging logging tool is complicated in the downhole.After the traditional acceleration correction method, there is still a slight saw-tooth effect in the borehole image.This effect makes the image quality decreased, and the multiple solutions of well logging interpretation increased.To solve the problem, this paper firstly analyzes the reasons of the saw-tooth effect in electric imaging logging.Then, a correction method based on the analysis of the relative speed of the instrument is proposed.In this method, the relative velocity curve of the instrument is set up by comparing the micro resistivity curves of each electrode, and the Kalman filtering model is used to predict the real depth of the image.The application example shows that the method can effectively reduce the saw-tooth effect in the image processing of electric imaging logging and improve the image display quality.