凝析油对降低CO_(2)驱油最小混相压力的影响

Effects of condensate oil on reducing the minimum miscible pressure of CO_(2) flooding

采用静态高压相平衡装置,373.15 K下,在CO_(2)原油体系中加入质量分数为1%、5%、10%、15%的凝析油时,测定气液相平衡数据。将原油视为一元假组分,采用由折光率(n)、相对密度(d)和摩尔质量(M)组成的n-d-M法结合线性规划(LP)的n-d-M-LP法与C-G法预测CO_(2)-原油体系的结构性质和临界参数;通过YSL四次状态方程对实验数据进行关联,得到不同体系的二元相互作用参数kij,然后计算得到CO_(2)原油体系的相平衡数据。结果表明:随着凝析油加入量的增加,CO_(2)原油体系的最小混相压力逐渐降低;通过四次状态方程拟合得到的计算值与实验值吻合良好,说明该热力学模型能够准确计算CO_(2)原油复杂体系的相行为。

The vapor-liquid equilibrium data of CO_(2) in crude oil with 1%,5%,10%,15%mass fraction condensate oil was measured at 373.15 K by a static high pressure phase equilibrium apparatus.The crude oil was regarded as one pure compound,and the structural properties and critical parameters of crude oil were predicted by C-G method and n-d-M-LP method consisted by refractive index(n),relative density(d)and molar mass(M)with linear programming(LP).Meanwhile,the regression analysis of binary interactive parameters of CO_(2) and crude oil system with YSL quartic equation of state was used to estimate the vapor-liquid equilibrium data under the same condition.Results showed that the minimum miscible pressure of CO_(2) and crude oil system decreased with the increasing of condensate oil,and the correlation values were well agreement with the experimental values by quartic equation of state,indicated that this thermodynamic model could accurately describe the phase behavior of complex CO_(2) and crude oil system.