Parameters Analysis and Correction Method for Seismic Converted Shear-Wave Splitting Based on Orthogonal Four Components

Theory and practice have confirmed that the propagation of converted transverse waves in azimuthally anisotropic media results in shear-wave splitting, causing diff erences in travel time and reflection amplitude between S1/S2 waves, which reduces the imaging quality and vertical resolution of converted transverse wave. Therefore, eliminating shear-wave splitting is one of the important steps in the imaging processing of converted transverse wave. Due to the limitations of actual data acquisition and signal-to-noise ratio, it is difficult to directly determine a set of orthogonal four components for shear-wave splitting analysis, which cannot achieve good correction processing results. To this end, starting from Alford rotation, an orthogonal four component equation system is derived, and the least squares method is used to stably solve the high signal-to-noise ratio orthogonal four components. Based on this, the crack orientation and fast/slow wave delay are estimated through azimuth and time-delay scanning, and the shear-wave splitting correction and fast/ slow wave separation are completed by layer striping from shallow to deep. The synthetic data and actual data calculations show that this method can achieve good azimuthal anisotropy correction, separation of S1/S2 waves, and accurate imaging.