A rotating magnetic guidance method for measurement while drilling

Aimed at the relative position and orientation measurement, a new measurement-while-drilling technique based on rotating magnetic field is developed in this paper. By studying the magnetic signals propagation, it was found that the rotating magnetic field is equal to combination of two orthogonal magnetic dipoles, and the characteristic magnetic signals of which can be used to localization the rotating magnet source, the characteristic signals can be determined with phase demodulation and amplitude demodulation of triaxial measureable magnetic signals by using Hilbert Transform. The simulation result shows that the localization error is less than 0.002 meters when the range between rotating magnet source and the target point is about 40 meters, and with the range getting closer, the error becoming smaller, the accuracy increasing. The rotating magnetic guidance method have great value for horizontal connection well drilling in coal bed methane development, SAGD parallel wells in heavy oil development and soluble salt mine development.