The impact of characterization methods on properties of reservoir fluids and crude oils: options and restrictions

Abstract

Methods selected for the characterization of reservoir fluids have significant impact on the estimation of physical properties and phase behavior needed in reservoir simulation for petroleum production. Characterization of reservoir fluids involves representing the fluid as a continuous, semi-continuous mixture or through a number of components/pseudocomponents with known basic characterization data. Understanding of various characterization schemes and their limitations is the key to selecting the right one in a reservoir simulator. Methods of characterization largely depend on the nature of reservoir fluid, and the type of available data for the fluid. The minimum data on the heptane-plus fraction of a reservoir fluid is specific gravity, and the complete data is the SCN analysis with molecular weight and density for each group. In this paper various options for characterization of different types of reservoir fluids and crude oils with respect to the type of available data and their limitations are presented. It is shown that for a light crude with only specific gravity available, it would be possible to obtain a good distillation curve. Type of data and the impact of characterization method on phase behavior and properties of reservoir fluids are also presented.