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The feasibility of transporting gas-to-liquids (GTL) products (natural gas chemically converted to liquid hydrocarbons) through an existing oil pipeline—the Trans Alaska Pipeline System (TAPS)—for bringing value to Alaska's vast stranded natural gas resources is currently being investigated. As part of this major project, the phase behavior measurement and modeling of GTL and Alaska North Slope crude (ANSC) oil blends have been carried out. The saturation pressures for various types of GTL and ANSC oil blends were measured in a conventional windows based PVT apparatus. The phase behavior of GTL and ANSC oil blends were also modeled by the Peng-Robinson and Soave-Redlich-Kwong equations-of-state. The measured and modeled saturation pressures were found to be in close agreement. The results also indicated that the GTL and ANSC oil blends would always exist as single-phase liquid under the current TAPS operating conditions. [ABSTRACT FROM AUTHOR]

The interfacial tension (IFT) of hydrocarbon fluids is commonly predicted by either the parachor method or the scaling law. The methods require equilibrium liquid and vapor phase composition and density. An equation of state would normally be required if experimental values are not available. However, the computation of density for simple hydrocarbons and reservoir fluids, despite the important advances achieved by cubic equations of state, still remains a weak link in these types of calculations. Thus, there exists a need to investigate the qualitative and quantitative effects, of such inaccuracies in the density, on IFT predictions. Moreover, the study presented in this work would be useful in reservoir engineering and enhanced oil recovery calculations. The results presented in this work indicate that the methods are highly sensitive to the inaccuracies in the density of both the liquid and the vapor phases. An error of around 10% in the liquid or the vapor density can result in an error of up to 200% in the estimated IFT. Two binary and one ternary mixture for which measured data on IFT, composition and density is reported in the literature form the basis of this study. [ABSTRACT FROM AUTHOR]

As part of a major project on studying the transportation of gas-to-liquids (GTL) through the existing Trans Alaska Pipeline System (TAPS), the density and viscosity of GTL and the Alaskan North Slope Crude (ANSC) and their blends were measured. All density and viscosity measurements were performed, using the Anton–Paar vibrating tube densitometer and a cone and plate viscometer respectively, at temperatures ranging from 20 oC to 60 °C at atmospheric pressure. The accuracy of the measured data has been ascertained. In addition to the density and viscosity data, other data reported for GTL and ANSC include compositions. Finally, generalized dens ty and viscosity correlations for the measured data are presented. [ABSTRACT FROM AUTHOR]