In this method, a Newton-type entropy maximization algorithm isĬombined with a Gibbs stability te.st to find number of phases and then a multiphase flash calculation is presented a thermodynamically rigorous method to find the number of phases Uses a modified Rachford-Rice monotonic objective function and the negative flash concept fo. Multiphase flash calculation method is necessary to improve the efficiency of such simulations.Ī new isenthalpic multiphase fla.sh calculation is described in this paper. Development of a robust and fast isenthalpic We describe the numerical approach for solving the tie line intersection equations, and we use slim tube test and compositional simulation data reported in the literature to show that the proposed approach can be used to calculate MMP accurately for displacements with an arbitrary number of components present. The MMP is calculated as the pressure at which one of the key tie lines becomes a critical tie line (a tie line of zero length that is tangent to the critical locus). Besides the tie lines that extend through the initial oil and injection gas compositions, there are nc-3 tie lines, known as crossover tie lines, that can be found from a set of conditions that require the extensions of the appropriate tie lines to intersect each other. The theory shows that in a displacement of an oil by a gas with nc components, the behavior of the displacement is controlled by a sequence of nc-1 key tie lines. It is found that the minimum absolute average relative deviation (AARD) of 6.7% is obtained by the methodology developed in this work, compared to the AARD of 35.6% obtained by running the commercial simulator.Abstract We describe and test a method for calculation of minimum miscibility pressure (MMP) that makes use of an analytical theory for one-dimensional, dispersion-free flow of multicomponent mixtures.
HOW TO CHANGE BIP IN CMG WINPROP SIMULATOR
Subsequently, the comparisons have been performed between this work and a commercial simulator in terms of the overall prediction accuracy of saturation pressures for the quaternary C 3H 8- n-C 4H 10-CO 2-heavy oil systems.
The optimal exponents in binary interaction parameter (BIP) correlations are obtained by best matching the measured saturation pressures. The heavy oil which is a complex mixture with unknown molecular structure is characterized as six pseudocomponents by using an exponential distribution splitting function and a logarithm-type lumping method. Theoretically, the volume-translated Peng-Robinson equation of state (PR EOS) coupled with a recently modified alpha function is applied as the primary thermodynamic model to reproduce the experimental measurements. A pressure-volume-temperature (PVT) setup is used to measure vapor-liquid phase boundaries (i.e., saturation pressures) and swelling factors at high pressures up to 11.1 MPa and elevated temperatures up to 373.35 K. Experimentally, a pure substance of CO 2 and a gas mixture consisting of 27.7 mol% C 3H 8, 23.9 mol% n-C 4H 10, and 48.4 mol% CO 2 are respectively introduced to dilute the highly viscous heavy oil. Techniques have been developed to determine vapor-liquid phase boundaries and swelling factors of CO 2-heavy oil systems and C 3H 8- n-C 4H 10-CO 2-heavy oil systems under reservoir conditions.
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