College of Geo- Exploration Science and Technology��Jilin University��Changchun 130026��China

Prediction of reservoir fracture is the key to explore fracture- type reservoir�� When a shear- wave prop- agates in anisotropic media containing fracture�� it splits into two polarized shear waves: fast shear wave and slow shear wave�� The polarization and time delay of the fast and slow shear wave can be used to predict the azimuth and density of fracture�� The current identification method of fracture azimuth and fracture density is cross- corre- lation method �� It is assumed that fast and slow shear waves were symmetrical wavelets after completely separa- ting��and use the most similar characteristics of wavelets to identify fracture azimuth and density��but in the ex- periment the identification is poor in accuracy�� Pearson correlation coefficient method is one of the methods for separating the fast wave and slow wave�� This method is faster in calculating speed and better in noise immunity and resolution compared with the traditional cross- correlation method�� Pearson correlation coefficient method is a non- linear problem��particle swarm optimization (PSO) is a good nonlinear global optimization method which converges fast and is easy to implement�� In this study�� PSO is combined with the Pearson correlation coefficient method to achieve identifying fracture property and improve the computational efficiency��