This document is an expanded abstract.


In this contribution, a robust theoretical approach was applied to predict the interfacial and phase equilibrium properties of real reservoir fluids. The modeling approach was based on an improved version of the Peng-Robinson equation of state (EoS) and on the Density Gradient Theory (DGT) for fluid interfaces. All the EoS and DGT parameters were obtained from literature correlations or calculated through a group-contribution method, leading to the computation of all the fluid properties in a fully predictive manner. The good agreement with volumetric, phase composition and interfacial tension data of multiple contact tests confirmed the superior predictive capabilities of the present modeling approach for describing key PVT properties of reservoir fluids.


Accurate description of interfacial and bulk phase equilibrium properties of reservoir fluids is crucial for the deployment of more efficient and economical petroleum engineering processes. In terms of the bulk phases, composition and volumetric properties are of major importance as they dictate the quality and quantity of the produced fluids [1]. Interfacial forces, on the other hand, play a key role in the multiphase flow of fluids in pipelines, surface equipment and reservoirs. A quantitative index of the interfacial forces is given by the interfacial tension. This property, although entirely related to the fluid phases in contact, influences several rock properties such as capillary pressure, wettability and relative permeability [2]. In this sense, interfacial tension is a key parameter that determines the displacement and accumulation of hydrocarbon fluids in the pore spaces of reservoir rocks and, therefore the ultimate recovery [1,2]. Together, interfacial and bulk phase properties are also of paramount importance for the development of more reliable compositional reservoir simulations [1].

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