Comparative Study of the C7+ Characterization Methods: An Object-Oriented Approach

Abstract

When using equations of state (EOS) to predict the phase behavior of hydrocarbon mixtures, problems occur with the C 7+ fraction that exists in such mixtures. Minimizing such problems requires either fine-tuning the EOS and/or characterizing the C 7+ fraction. C 7+ characterization is the most important, yet most difficult step associated with the description of reservoir fluids. Several methods have been proposed for characterizing the C 7+ fraction. Collectively, these methods are grouped into two main categories: correlation and splitting and lumping. This paper revisits the most common characterization methods presented in the literature, which have received wide acceptance. In addition, a worthwhile contribution of this paper is the proposed improvement to the Katz constant-parameter splitting method. A further contribution is that the resulting program is coded in an object-oriented manner, which offers flexibility in programming and allows the different parts of the code to be described easily and in a natural manner as if they were real world objects.