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.