随钻测井钻井液脉冲信号基线漂移的矫正

钻井液脉冲信号携带了随钻测量系统的参数信息，其在传输过程中受到各种噪声的干扰，信号不平稳且存在基线漂移。为去除钻井液脉冲信号的噪声和基线漂移，使其能满足信号解码的要求。采用小波变换技术过滤信号噪声，检测出脉冲位置，并采用中值滤波的方法矫正信号中出现的基线漂移。实验结果表明，小波变换能够有效地去除钻井液波信号中的噪声，中值滤波很好地解决了钻井液脉冲信号中的基线漂移现象。采用中值滤波的方法去除基线漂移完全满足现场的要求，为钻井液波信号的解码奠定了基础。

Mud signal baseline drift rectification in measurement while drilling

Drilling liquid signals carry a lot of information parameters of the measurement while drilling (MWD) system. They are disturbed by varieties of noises in transmission. The signals are not smooth and have baseline drift. In order to wipe off noises and rectify baseline of the drilling liquid signal and to satisfy the demand of signal decoding, the drilling liquid signal is filtrated by wavelet transformation and the position of the pulse is checked out. After that the baseline drift in signal is rectified by median filter. The experiment result shows that wavelet transformation can wipe off the noises effectively and median filter can solve the phenomenon of baseline drift in the drilling liquid signal completely. The drilling liquid signal processed by median filter meets the requirement of well field and lays solid basis for signal decoding.