Abstract: According to the split phenomenon of shear wave transmitted in anisotropic strata, the natural or induced fractures parallel or oblique cross to a bore hole could create shear wave anisotropic characteristic. The size of anisotropy reflects the growth degree of fractures. The polarization direction of fast shear wave indicates the trend of fractures. Hence, the fast and slow shear wave information could be picked-up using dipole acoustic imaging log data, obtaining the size of anisotropy, from which the validity and trend of fractures in Anpeng area are evaluated qualitatively.

Key words: fracture, acoustic wave, shear wave, trend, anisotropy