Finite-difference approach to 3D simulation of acoustic/elastic waves propagation in a borehole and surrounding 3D heterogeneous elastic medium is presented. It is based on explicit second-order staggered grid FD scheme that solves the first-order system of elastic wave equations in cylindrical coordinates. In order to bound area of computations original version of Perfectly Matched Layer (PML) developed before in (Kostin et al., 2002) for axially symmetric statement is modified for general 3D situation. Essential 3D nature of the waves processes for realistic models claims necessity to use parallel computations. Parallelization is performed on the base of domain decomposition approach and implemented under Message Passing Interface (MPI). Results of numerical experiments are presented and discussed.