Analysis Methodology for Azimuthal Anisotropy

Here is a prescription for the implementation of a data-driven analysis procedure for determining accurate horizontal anisotropic velocity parameters. The high resolution method is simple and fast and can be quickly applied to 3D surveys. Wide and multiple azimuth datasets are making it clear that azimuthal anisotropy is more prevalent than most imagers realize. In many regions, significant horizontal stress can deform the rock or pore matrix or cause fracturing that result in directionally dependent horizontal velocity or horizontal transverse isotropy (HTI). This method extends the parameterization accuracy by defining an elliptical gradient technique. The normally occurring abundant spatial sampling of data provides sufficient statistics for computing a gradient surfaces and finding the minimum to solve for the anisotropy parameters.