Finite-difference Simulation of Acoustic Log in 3D Heterogeneous VTI with Attenuation

On the base of the application of a finite-difference approximation of an initial boundary value problem for elastic wave equations (velocity/stress formulation), numerical method and its algorithmic implementation have been developed in order to perform a computer simulation of sonic logging. The very general statement is dealt with – surrounding medium allowed to be 3D vertical transversely isotropic heterogeneous with attenuation and source can be located at any point inside or (VTI) outside the well. To provide the most precise description of the sharpest interface of the problem – the interface of the well, we formulate the problem in cylindrical coordinates with axis directed along the well. In order to truncate area of computations two approaches are used: classical version of Perfectly Matched Layer (PML) and extension on the base of optimal grid. Implementation of parallel computations is done via Domain Decomposition Data exchange between Processor Units is performed with the help of Message Passing Interface library. Results of numerical experiments for VTI media are presented and discussed.