Physical properties phase envelopes

The collection of representative reservoir fluid samples is important in order to establish the PVT properties - phase envelope, bubble point, Rg, B, and the physical properties - composition, density, viscosity. These values are used to determine the initial volumes of fluid in place in stock tank volumes, the flow properties of the fluid both in the reservoir and through the surface facilities, and to identify any components which may require special treatment, such as sulphur compounds. 

If the liquid mixture is extremely non-ideal, liquid phase splitting will occur. Here, we first consider the hypothetical ternary system. The physical properties are adopted from Ung and Doherty [17] and Qi et al. [10]. The catalyst is assumed to have equal activity in the two liquid phases. The corresponding PSPS is depicted in Fig. 4.5, together with the liquid-liquid envelope and the chemical equilibrium surface. The PSPS passes through the vertices of pure A, B, C, and the stoichiometric pole Jt. The shape of the PSPS is affected significantly by the liquid phase non-idealities. As a result, there are three binary nonreactive azeotropes located on... 

Figure 2 also shows the density (p) vs temperature phase diagrams of ( () -(, I Ii -N and CO -C Hi -() systems calculated from PR equation of state.The system is single phase outside the envelopes, and separates into two phases in the envelopes. The results in Figure 2 indicate that the differ-rence of p T curves of the two systems is not considerable. The main reasons are that the physical properties of N2 and O2 are similar and their concentrations in the corresponding solutions are low (0.1 mol%). This suggests that N2 can be used to replace O2 for the phase behavior measurements. 

During the evolution of many stars, mass loss during the giant branch phase modifies a star s physical properties. Studies of the stellar envelopes that result from this mass loss process indicate that evolved stars are a significant contributor of processed material to the interstellar medium. Since this processed material is eventually incorporated into the next generation of stars, an understanding of evolved stars and their mass loss mechanisms is key to understanding the entire star formation process. 

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