Petroleum Reservoir Simulation Using Finite Volume Method with Non-structured Grids and Parallel Distributed Computing

This paper discusses the implementation of a numerical method for simulating petroleum reservoirs, based on finite volume technique using non-structured grids, designed for parallel computing platforms with distributed-memory, particularly for clusters of workstations. Non-structured meshes are used in order to enhance the capability of conforming the irregular boundary of the reservoir allowing better application of boundary conditions and enabling an easier specification of geological faults. The parallel implementation is based on the domain decomposition, where the original reservoir is decomposed into several domains, each of which given to a separate processing node. All nodes then execute computations in parallel, each node on its associated sub-domain. The parallel computations include initialisation, coefficient generation, linear solution on the subdomain, and inter-node communication. The exchange of information across the subdomains, or processors, is achieved using the message passing interface standard, MPI. The use of MPI ensures portability across different computing platforms ranging from massively parallel machines to clusters of workstations. In order to validate the solution procedure, the well-known five-spot problem is simulated. The execution time and speed-up are evaluated through comparing the performance of different numbers of processors. The results indicate that the parallel code can significantly improve prediction capability and efficiency for largescale simulations.