Evaluation on formation structure from cross—dipole acoustic logging data

With the effective combination of dipole and mono- pole technique,XMAC-Ⅱprovides the best measure- ment to acquire time difference of compressional,shear, and Stonley wave.This paper elaborates the method which uses the reflex coefficient of Stonley,fluid-moved index and the anisotropy by extracting the fast and slow wave information,to identify fractures and evaluate the effectiveness of fractures.Through application on frac- tured reservoir in B281well ofⅩⅩregion,the evaluation result of fractured reservoir is found to be closely related with the imaging data,which provides a good technical method to identify fractures.