The oil reservoir simulators black (black oil) are able to simulate these systems where gas, oil and water in any proportion. This simulator is the most commonly used in oil reservoirs and the main assumption is that the compositions of oil and gas do not change significantly with the depletion.
Three equations are used to express the mass conservation of the three components (water, oil and gas in each block), does not consider the solubility of gas and oil in water or existence of oil in the gas phase. Gas solubility in oil is a function of pressure, does not consider the existence of water in the gas phase or oil.
The simulation of black oil or black oil, is useful in simulation of injection processes of water or immiscible gas where there are expected changes in the composition of fluids. Can model the flow of water, oil and gas taking into account variations in gas solubility in oil as a function of pressure.