ELIMINATION OF ADAPTIVE-GRID INTERFACE ERRORS IN THE DISCRETE CELL-CENTERED PRESSURE EQUATION

Classical cell centered discretization of the reservoir simulation pre ssure equation on an h-adaptive grid results in an O(1/h) leading trun cation error at the grid interface. A new flux continuous finite volum e correction is presented together with an improved version of a previ ously proposed correction. While both corrections eliminate the leadin g error, the new correction exhibits the best convergence rates and ha s the following properties: the resulting matrix is in general symmetr ic positive definite, diagonally dominant for locally isotropic spatia lly varying coefficients, convergence to O(h) is demonstrated, and sup port of the standard approximation is retained, ensuring a fully impli cit implementation. Results computed by the uncorrected classical sche me and both correction schemes are compared for two phase flow simulat ions with multilevel dynamic local grid refinement. (C) 1996 Academic Press, Inc.