Abstract
Accurate predictions of physical properties for reservoir fluids are necessary for many calculations in petroleum engineering. These physical properties have been correlated as functions of fluid compositions. Under conditions which cause the reservoir fluid to separate into liquid and vapor phases at equilibrium, equilibrium ratios permit the calculation of the composition of each phase and the relative amount of each phase present. The magnitude of a particular equilibrium ratio is a function of pressure, temperature, composition of the mixture under investigation, and the volatility of the component. In this investigation, the critical convergence pressure has been defined. It is proposed as a more accurate method to account for the effects of mixture composition. This method resulted in improving the per cent of usable solutions from 91.6% to 97.9% based on 191 available complex mixture systems. The improvement in average deviations for equilibrium ratios selected ranged from 0.8 to 11.5 per cent. In addition, methods to predict the properties of the heptanes-plus in the derived phases have been presented.
Schlaudt, Robert Christian (1968). Critical convergence pressure--A criterion for selecting equilibrium ratios for complex hydrocarbon systems. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -172870.