CO2驱油过程中原油胶质对沥青质沉积的影响

Effect of Colloidal Concentration on Asphaltene Deposition during CO2 Flooding

李兆敏 王美佳 武守亚 张 超 席玲慧 吕广忠

LI Zhaomin WANG Meijia WU Shouya ZHANG Chao XI Linghui LYU Guangzhong

沥青质沉积严重影响油田开发效果，为明确CO2驱替过程中胶质对于沥青质沉积的影响，本文以不同胶质沥青质质量比的原油模拟液为研究对象，通过微观可视驱替实验，模拟CO2驱替过程中沥青质沉积现象，确定其组分含量、物性、固相颗粒大小变化，分析胶质对沥青质稳定性的影响。研究结果表明：胶质以圆球状包裹沥青，对沥青质起着稳定作用；当胶质沥青质质量比从1∶1升至6∶1时，沥青质沉积量、沉积潜力均先增大后减小，黏度则先减小后增大，胶质与沥青质质量比为2∶1时，黏度达到最低，沥青质沉积量、沉积潜力最大。沥青质沉积与胶质含量有关；沥青质胶质间存在一对作用力—吸附力与分散力，沥青质沉积量与这对力的作用效果相关。 图16参25

Asphalt deposits seriously affect the development of oilfields. In order to clarify the influence of colloid on asphaltene deposition in the process of CO2 flooding，taking simulated crude oil with different colloid and asphaltene mass concentration ratio as the research object，the microscopic visual experiments were carried out to simulate the asphaltene deposition and to analyze the change of composition，physical properties，and solid particles size，and the effect of the colloid concentration on the stability of asphaltene was explored. It is indicated that the asphaltene was wrapped in colloid with a spherical shape，which could keep asphaltene stable. When the mass ratio of colloid to asphaltene rose from 1∶1 to 6∶1，the asphaltene deposition and sedimention potential of the simulated crude oil increased first and then decreased，while the viscosity of the simulated crude oil decreased first and then increased. The viscosity was the lowest，and asphaltene deposition and sedimention potential were the largest when the mass ratio of colloidal to asphaltene was 2∶1. The asphaltene deposition was directly related to the colloid content. It was verified that there was a pair of forces between the colloid and the asphaltene—adsorption force and dispersing power. The amount of asphaltene precipitation was related to the effect of this pair of forces in the process of CO2 flooding.

10.19346/j.cnki.1000-4092.2019.04.016