CO2-EOR技术具有提高原油采收率与CO2减排的双重效益。在CO2-EOR中，CO2原油体系的密度是影响CO2运移扩散的关键参数，对驱油效率及CO2安全封存具有重要意义。本研究以此为背景，拟基于磁悬浮天平基础物性测试平台模拟油藏条件，进行CO2模拟原油多元体系的密度及超额体积特性研究，探析温度、压力、CO2浓度及烷烃碳数对CO2模拟原油多元体系密度及超额体积的影响；研究原油密度与原油特性的相关性，解析烷烃结构、烃族信息及混合比例对CO2模拟原油体系密度特性的影响规律；研究溶液非理想性与分子间作用的联系，探明CO2、烷烃分子及不同组分间的作用形式与相互作用，揭示CO2模拟原油多元体系密度特性的变化机理；基于获得的实验数据，通过引入考虑了烷烃碳数的纯物质参数与分子间相互作用参数，建立CO2模拟原油多元体系密度的统计缔合流体理论模型，为提高原油采收率及CO2安全封存提供理论指导。

CO2-EOR is the CO2 utilization and storage technology for it not only enhances oil recovery, but also can storage CO2. As one of critical physical parameters during CO2-EOR, density has great significance for the displacement process and the security of the CO2 storage. Based on the CO2 storage in the oil reservoir, we intend to simulate the oil reservoir geological conditions and measure the densities of the CO2 and oil multicomponent system, also the excess volumes of the solutions will be obtained. The influences of the temperature, pressure, CO2 concentration, and carbon number on the density and the excess volume will be researched. The correlation between the physical properties and the characteristics of the simulated oil will be investigated, including the structure, hydrocarbon group information, the mixing component and constitute. The relation between the molecular interaction and the non-ideality will be studied, the interaction form between the CO2 and oil molecules will be discussed and the change mechanisms of the density and excess volume will be clarified. Based on the experimental data, the SAFT equation of state will be established to predict the properties of the CO2 and oil mixtures, which correlated the pure component parameter, the interaction parameter with the carbon number. The study provides the basic data and theoretical direction for the CO2 storage in the oil reservoir.