Abstract: Using a difference method of irregular meshes, a numerical model for 2-dimensional oil-water reservoir simulations is presented and its numerical results of two examples have been given when IMPES method is adopted. The numerical results of example 1 are in good agreement with the analytic solution. The number of difference meshes used for example 1 is less than that used in Petrosa's model of hybrid grid for the same example and the method given in this paper is more efficient and convenient. It is difficult to solve the problem of example 2 for the difference mehtod of rectangular meshes. However, satisfying results are also obtained when the method given here is used for the numerical solution of the example 2. The results show that this method of irregular difference meshes can be applied flexibly to probems of reservoir simulations with a complex boundary and a complex structure of stratum.

Key words: irregular difference meshes, IMPES method, 2-dimensional 2-phase reservoir simlation