DOWNHOLE MWD SIGNAL ENHANCEMENT, TRACKING, AND DECODING

摘要

A method for transmitting data from a MWD system at the BHA of a drill string may include transmitting the data in a MWD signal from the MWD system. The MWD signal may be modulated at a position closer to the surface onto a mud pulse modulated signal. The mud pulse modulated signal may be generated by a downhole friction reducing device. The downhole friction reducing device may include a mud motor. The mud motor may create pressure pulses based on its speed of rotation. The downhole friction reducing device may include a modulating valve. The modulating valve may be electromechanically or mechanically operated. The modulated signal may be detected at the surface by a receiver using one or more pressure or flow sensors. The receiver may use one or more harmonics of the modulated signal to receive the data.