Abstract: Indoor lab study and corresponding modeling are the bases of researching miscible gas-flooding mechanisms and evaluating gas in-jection projects. This paper presents a theoretical model of phase equilibrium estimation for pressure-composition and multi-contact miscible. experiments of gas injection, creates a systematic evaluation method of gas-flooding miscibility and displacing mechanism by simulating PVT data and matching the pressare-composition experiment and miscible-immiscible flood slim-tube experiment by means of Equation of State and available tools. Taking a real reservoir as an evaluating case, such a method established from lab study has been validated, hence can be used to provide reliable lab and theoretical bases for evaluation of design of miscible gas-flooding project of oilfields.

Key words: gas injection, miscible flooding, vaporizing, simulation, mechanism, evaluation