Method for orienting horizontal components of borehole geophones during micro-seismic monitoring

The invention discloses a method for orienting horizontal components of borehole geophones during micro-seismic monitoring. The method includes acquiring first-arrival waveforms of seismic longitudinal waves; mutually correlating waveforms component records and component average values and keeping the component records with correlation coefficients larger than 0.8; identifying first-arrival jumping moments of direct-arrival longitudinal waves by the aid of sliding energy ratios of front and rear time windows, reading time-variable amplitude values of X, Y and Z coordinate components corresponding to sampling points one by one in 2 or 3 periods around first-arrival jumping points, and drawing three-dimensional graphs of vibration track curves of particles; searching local maximum values to obtain enveloping surfaces of the space curves; determining rotation angles of the horizontal components of the borehole geophones in relative coordinate systems and determining three-component azimuth angles. The internal radial maximum values of the enveloping surfaces indicate actual longitudinal wave propagation directions. The rotation angles of the horizontal components of the borehole geophones are included angles between the projection of the actual longitudinal wave propagation directions in the horizontal plane and the projection of the directions from ground earthquake source points to the borehole geophones in the horizontal plane. The three-component azimuth angles are the sums of the horizontal components in the directions from the ground earthquake source points to the borehole geophones and the rotation angles of the horizontal components.