tailieunhanh - Orr, F. M. - Theory of Gas Injection Processes Episode 10

Tham khảo tài liệu 'orr, f. m. - theory of gas injection processes episode 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . DEVELOPMENT OF MISCIBILITY 171 Figure Saturation profiles for the displacements of Fig. 21 . Figure Effect on MMP of variations in injection gas composition for displacements of oils of fixed composition. The initial oils have fixed CH4 mole fraction 10 percent but varying ratios of C4 to C10 21 . 172 CHAPTER 6. FOUR-COMPONENT DISPLACEMENTS line that controls miscibility changes from the initial oil tie line to the crossover tie line. Enriching the initial mixture in C4 also reduces MMPs substantially because the initial and crossover tie lines move closer to the critical locus at any pressure. Volume Change The analyses of Sections and showed that local flow velocity which differs from propagation velocity of a composition varies along the displacement length if components change volume as they transfer between phases or if the partial molar volume of a component is a function of the composition of a mixture. However the local flow velocity remains fixed for a composition variation along a tie line because the compositions of the phases see Section and therefore their densities remain fixed see Section . Thus local flow velocity changes only across shocks that enter or leave the two-phase region across shocks that connect two tie lines and along rarefactions between tie lines. In view of the additional complexity of displacements with volume change it is remarkable that the same key tie lines are part of the solution composition route whether or not volume change plays a role. To see why that statement is true consider the eigenvalue problem stated in Eq. . When the flow velocity varies in space the eigenvalue problem can be written as H u - A G u u 0 where H u 9Hị 9Hị 9Hị 9Hị - dz1 dz2 9z3 9vn 9H2 9H2 9H2 9ỈỈ2 dz-1 dz2 dz3 dvn 9H3 9H3 9H3 9H3 dz-1 dz2 dz3 di ii 9H3 9H3 9H3 9HÍ dz1 dz2 dz1 9vp _ and G u 9Gị 9Gị 9Gị 0 dzi dz2 dz3 9g2 9ơ2 9G2 9zl dz2 dz3 9g3 9ơ3 9Gị pi dzi dz2 dz3 m dzi dz2 dz3 0 uT dz-1 dz2