An Improvement of Velocity Variation with Offset (VVO) Method in Estimating Anisotropic Parameters

Abstract

AbstractSeismic anisotropy causes deviation of traveltime reflection from hyperbolic moveout. The deviation can be seen at far offset and its deviation depends on anisotropic parameter and offset. This paper discuss velocity variation with offset (VVO) method as a tool for estimating anisotropic parameters; ε and δ. Anisotropic parameter is one of important aspect in seismic anisotropy analysis. While other methods use non-hyperbolic moveout for estimating anisotropic parameter, VVO method uses hyperbolic assumption for moveout correction and leave reflector unflat at far offset because anisotropy. The method calculates residual traveltime and then changes it into anisotropy velocity to obtain anisotropic parameter using linear inversion method. This paper provides an improvement and limitation of VVO method in estimating anisotropic parameter. Comparison between VVO method and other established method is discussed theoretically in this paper. To test the method, synthetic model is built and the result show promising outcome in predicting ε. Meanwhile accuracy for δ estimation depends on accuracy of moveout velocity. Advantage of VVO method is that ε and δ can be estimated separately using P-wave gather data without well information.