Massively parallel computing techniques can overcome limitations of problem size and space resolution for reservoir simulation on single-processor machine. This paper reports on our work to parallelize a widely used numerical simulator, known as TOUGH2, for nonisothermal flows of multi-component, multiphase fluids in three-dimensional porous and fractured media. We have implemented the TOUGH2 package on a Cray T3E-900, a distributed-memory massively parallel computer with 695 processors. For the simulation of large-scale multicomponent, multiphase fluid flow, the requirements for computer memory and computing time are extensive. Because of the limitation of computer memory in each PE (processing element), we distribute not only computing time but also the memory requirement to different PEs. In this study, the METIS software package for partitioning unstructured graph and meshes is adopted for domain partitioning, and the Aztec linear solver package is used for solving linear equation systems. The efficiency of the code is investigated through the modeling of a three-dimensional variably saturated flow problem, which involves more than one million gridblocks. The execution time and speedup are evaluated through comparing the performance of different numbers of processors. The results indicate that the parallel code can significantly improve capacity and efficiency for large-scale simulations.

You can access this article if you purchase or spend a download.