A method of mixed-paradigm parallel programming computerized simulation in a computer platform of shared and distributed memory parallel computers of component compositional variables of oil and gas phases of component hydrocarbon fluids of a giant subsurface reservoir to simulate performance and production from the reservoir, the giant subsurface reservoir being simulated by a model partitioned into a number of cells arranged in a three-dimensional coordinate system of a plurality of horizontal layers of cells, each horizontal layer comprising a plurality of cells having horizontal lateral dimensions along first and second intersecting horizontal axes and vertical dimension along a vertical axis, the simulation being based on available geological and fluid characterization information for the cells and the reservoir, and comprising the highly-parallelized computer processing steps of:
- (a) forming a computed measure of equilibrium compositions in a shared memory supercomputer of the computer platform for individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids with Open MP parallelization of data regarding the component compositional variables in the number of cells in the giant reservoir along the first horizontal axis;
- (b) forming a computed measure of equilibrium compositions in a distributed memory supercomputer of the computer platform for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids with MPI parallelization of data regarding the component compositional variables in the number of cells in the giant reservoir along the second horizontal axis;
- (c) forming a computed measure of species balance in the shared memory supercomputer of the computer platform for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids in the number of cells in the giant reservoir along the first horizontal axis;
- (d) forming a computed measure of species balance in the distributed memory supercomputer of the computer platform for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids in the number of cells in the giant reservoir along the second horizontal axis;
- (e) forming a computed measure of water balance for water component fluid in the number of cells in the giant reservoir;
- (f) forming a total volume balance to confirm that the total computed measures of species balance for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids and the computed measure of water balance for the water component fluid in the number of cells in the giant reservoir does not exceed a saturation of one;
- (g) determining residuals for the computed measures of equilibrium compositions and species balance for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids in the number of cells in the giant reservoir;
- (h) updating a solution vector based on the determined residuals for the computed measures of equilibrium compositions and species balance for the individual hydrocarbon species in the oil and gas phases of the component hydrocarbon fluids in the number of cells;
- (i) determining if the residuals for the equilibrium compositions and species balance for individual hydrocarbon species of the oil and gas phases of the component hydrocarbon fluids in the number of cells are within a level of user-prescribed tolerances;
- and,
- (j) if not, repeating steps (a) through (i) based on the updated solution vector;
- or
- (k) if so, forming an output display of the component compositional variables of the individual hydrocarbon species of the oil and gas phases of the cells at desired locations in the giant subsurface reservoir to simulate performance and production from the giant reservoir.