Fluid Characterization in a Gas Condensate Reservoir: The Effect of Lumping Techniques

Several problems are associated with “regrouping” the original components into a smallernumber without losing the predicting power of the equation of state. These problems include (A) Howto select the groups of pure components to be represented by one pseudo-component. (B) Whatmixing rules should be used for determining the EOS constants (pc, Tc, and ω) for the new lumpedpseudo- components? In this paper the results of the lumping methods are compared with the data forgas condensate systems to find accurate lumping method for accurate fluid characterization. For thispurpose, Whitson’s lumping scheme, Pedersen lumping scheme, Danesh et al. lumping scheme, Leeet al. lumping scheme, Behras and Stanndler lumping scheme are used as lumping scheme and Leemixing rules was used for calculation of thermodynamics properties of lumped group. To compare theImpact of each Lumping method, its effect was examined on the phase diagram. The results show thatthe Whitson lumping scheme (it is grouping the hydrocarbon from C7 to C16+ into 4 groups) can predictthe phase diagram of this gas condensate systems fluid with good approximation, the Pedersen lumpingscheme (it is grouping the hydrocarbon from C7 to C16+ into 3 groups ) can predict the phase diagramof this gas condensate systems fluid somewhat and the Pedersen lumping schemes and Danesh et al.lumping schemes (it is grouping the hydrocarbon from C7 to C16+ into 4 groups) approximately predictedthe same phase diagram and the Lee et al. lumping scheme (it is grouping the hydrocarbon from C7to C16+ into 3 groups) can predict the phase diagram of this gas condensate systems fluid exactly.Therefore, the Lee at al. lumping scheme has very good accuracy compared to the other methods. Also,All Lumping Scheme has an effect on dew point line of phase diagram.