Abstract: Alford matrix rotation and linear transformation methods have been studied and used to inverse the data acquired by advanced cross-dipole acoustic array logging tool. From the data inversion we gained the direction and the quantity of the anisotropy of the media around the borehole. The validi ty of the inversion methods and the programs have been verified through processing synthetic data and the features of these two methods has been compared. The inversion programs have been applied to processing field data and the results of inversion are satisfactory.

Key words: anisotropy, inversion, Alford rotation, linear transformation, flexural wave, four componets data