Isothermal, isobaric two-phase flash calculations for compositional reservoir simulations

Compositional reservoir simulation involves a huge number of PT flash calculations which spend an important percentage of CPU time. From the other hand any isothermal flash algorithm is encountered with two major problems, which are proper selection of initial estimates and slow rate of convergence in the critical region. These two types of problem may violate the convergence of flash calculations which in turn causes failure of reservoir simulation. Thus reliable and efficient flash algorithms are required to ensure rapid and safe convergence. Two types of flash algorithms are presented and compared two each other. First is the Successive Substitution method and the second is a method with Broyden updates of Jacobian inverse. Some examples are presented to illustrate the capability Quasi-Newton of the proposed methods. In all cases an equation of state is used to provide relatively simple and reasonably accurate thermodynamic models.

کلیدواژه ها:

Two-phase flash ، Solution method ، Cubic equation of state