ABSTRACT
A static local grid refinement technique has been developed and implemented in a three dimensional, three phase reservoir simulator. The technique increases simulator accuracy without a major increase in computing cost. The method performs a "domain decomposition" whereby rectangular regions (called windows) are chosen from a coarse grid and refined in all three dimensions. Areal grid lines terminate when they hit the boundary of the refined domain. They need not be extended to the boundary of the model, as is the case in our current simulators. An efficient linear equation method is used which takes full advantage of the domain decomposition. Using this technique, the time required to solve a multi-window model increases linearly with the number of windows – not exponentially, as would be the case when no advantage is taken of the matrix structure. Results for several idealized test cases are given.
