  The two-phase oil-water flow in natural fractured reservoirs and its
numerical methods are introduced in this paper, where the fracture is modeled
by the dual porosity method. Efficient numerical method, including the finite
difference method, CPR-FPF preconditioners for linear systems and effective
decoupling method, are presented. Parallel computing techniques employed in
simulation are also presented. Using those numerical methods and parallel
techniques, a parallel reservoir simulator is developed, which is capable of
simulating large-scale reservoir models. The numerical results show that our
simulator is accurate and scalable compared to the commercial software, and the
numerical methods are also effective.
