Physical Modeling And Experimental Analysis Of Seismic Responses In EDA Media

The time difference (TD) between slow and fast shear waves as well as their amplitude versus azimuth (AVA) curves on seismic shear wave splitting records in EDA media can be used to determine the vertically aligned fracture's density, stripe and properties of the media. Therefore, the right TD and AVA curves are very important in seismic data processing and interpretation. However, it is difficult to calculate TD and map AVA curve for the splitting shear wave's irregular events which usually appears in twisting, tilting and trembling mode due to noises and poor observing conditions. In this paper a "constant travel time and velocity principle" is proposed that means the travel time and velocity of splitting shear waves invariable with the fracture set's stripe. Based on this principle the average method (AM) and instantaneous amplitude method (IAM) are proposed also for calculating TD and mapping AVA curve based on physical modeling data which included four kinds of splitting shear waves from two orthogonal shear waves S1 and S2 . The results show that those methods eliminate the influences of record's noise on TD and AVA curves. The algorithms may be more efficient in noise-rich data processing and may be useful for practical work.