ParSol is a library for semiautomatic parallelization of data parallel algorithms. It offers sequential and parallel arrays to be used in C/C++ algorithm implementations. The tool is developed as an extensible software package by using object–oriented techniques. ParSol uses MPI for interprocess communication. In this article, issues of application of parallel arrays for parallelization of MfsolverC++ are discussed. This solver simulates two-phase immiscible flow in porous media. A short description of the mathematical model is given and a basic information on the finite-volume approximation scheme is presented. Results of computational experiments are presented.