Can We Build Geologically Consistent Well-Tied TTI Velocity Models from 3D Seismic and VSP?

Anisotropy is very important to 3D seismic PSDM for building well-tie velocity models. VSP can serve as one of the critical components in estimating the anisotropic parameters. Zero offset VSP is used to estimate the quality factor Q which is used to correct the phases of the seismic data in prestack gathers. We propose to expand the WVSP recording levels from the first major velocity boundaries of any well paths such as the top Miocene in offshore West Africa, down to the target with 0.5-1.0km intervals in the wellbore. Integrating the WVSP traveltimes in the tomographic inversion of 3D seismic, we are hopeful that the TTI velocity model can be built geologically consistently. The PSDM volume from such TTI models will tie to the wells. We show an example from offshore West Africa that the PSDM results from such an integrated effort for TTI model building correlate the 3D seismic very nicely to the VSP images in extensive depth intervals in the wells.