Patent ID: 7689397

Claim:
A computer executable method for performing black oil delumping, the method comprising: converting a wellstream in a black oil reservoir simulation into a compositional wellstream enabling reconstitution of a set of composition and component molar rates of a production well; wherein the delumping method is adapted for retrieving component molar rates n i , i=1 . . . N c , wherein N c is a number of components and wherein a component molar rate is a product of a total molar rate multiplied by a component's mole fraction, and wherein the converting step comprises: (a) performing a phase mass rate calculation; (b) performing a phase composition calculation; and (c) performing a total composition and component molar rates calculation; and wherein step (a) for performing the phase mass rate calculation includes calculating the phase mass rates of vapor and liquid using the relations: phase mass rate of vapor, Q m v =Q m gv +Q m ov , and phase mass rate of liquid, Q m L =Q m oL +Q m gL , where Q m gv , Q m ov , Q m oL and Q m gL are mass rates of the free gas, vaporized oil, liquid oil, and dissolved gas respectively.