Migration-driven azimuthal velocity analysis -----Tentative workplan for 2010 Bo Zhang, Kui Zhang, Kurt J. Marfurt ConocoPhillips School of Geology & Geophysics, University of Oklahoma Introduction Wide azimuth P-wave data offers the opportunity for fracture detection. Two methods will be employed to evaluate the P-wave velocity variation with azimuth to predict fractures, one is based on the migration-driven velocity analysis, the other is the inversion of fast and slow velocities by events alignment procedure. Then we will compare the results and efficiencies of the two methods. Approach Two Theory According to Tsvankin’s(1997) study, the travel time equation expressions is: Approach One Maximum Semblance ------- the source-receiver azimuth ------- the two way zero-offset traveltime 10% So, the equations for the gather can be expressed by the following matrix: B0 -10% C0 In the above matrix, the travel time can be acquired by the following equation: 00 1800 1 can be achieved by the event alignment procedure which is illustrated by Figure 2. Fig 2. Event alignment procedure flow chart Fig 1 . Velocity driven migration chart The azimuth of Vfast and Vslow can be obtained by the following equation. Figure 3 shows the elliptical velocity variance, Acknowledgement we thank all the colleagues and sponsors of AASPI. Reference Tsvankin I, 1997a, Moveout analysis in transversely isotropic media with a tilted symmetric axis, Geophysics, 45, 479-512 Tsvankin I, 1997b, Reflection moveout and parameter estimation for horizontal transverse isotropy, Geophysics, 62, 614-629 Edward Jenner, 2001, Azimuthal anisotropy of 3-D compressional wave seismic data Where can be obtained by the following equation, Fig 3. Azimuthal variation of NMO velocity