Wang Peng, Ma Wenguo, Zhang Yunbao, Yan Qiuyan
Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China.
University of Chinese Academy of Science, Beijing 100049, China.
Int J Anal Chem. 2020 Jun 22;2020:2538521. doi: 10.1155/2020/2538521. eCollection 2020.
Polymer viscoelastic solution is the non-Newtonian fluid and widely used in oil production. In the process of seepage, the mechanism of the polymer solution with different molecular coil dimensions (Dh) flooding on remaining oil is unknown. By using the dynamic light scattering instrument, the molecular coil dimension of the polymer solution is tested. By using the HAAKE rheometer, the creep recovery test data of the polymer solution under the same creep time condition are obtained. The effects of polymer solutions with different Dh on residual oil are observed, by using the visible pore model. The results show that the higher the molecular weight ( ) of the polymer, the larger the size of the molecular coil dimension. The elasticity characteristics of the polymer solution are sensitive to the molecular coil dimension. As Dh of polymer molecules becomes larger, the contribution of the elastic portion to the viscosity of the polymer solution increases. The higher the of polymer is, the longer the molecular chain is and the size of Dh is larger. On the condition of the polymer solution with different with 2.5 g/L, when Dh is between 320.0 nm and 327.8 nm, the ratio of the elastic part in the apparent viscosity exceeds the proportion of the viscous part, and the polymer solution composition after these data can be used as a comparative study of elasticity for residual oil use. In the visible pore model, the pore-throat ratio is 3.5, the of water flooding is 54.26%, the of the polymer solution with Dh = 159.7 nm is 75.28%, and the increase of is 21.02% than that of water flooding. With the increase of Dh to 327.8 nm, the final of the experimental polymer solution is 97.82%, and the increase of of the polymer solution than that of water flooding is 43.56%. However, in the model with a pore-throat ratio of 7.0 and the same polymer solution with Dh = 327.8 nm, the increase of of the polymer solution is only 10.44% higher than that of water flooding. The effect of the polymer solution with the same Dh is deteriorated with the increase of the pore-throat ratio.
聚合物粘弹性溶液是非牛顿流体，在石油生产中广泛应用。在渗流过程中，不同分子线团尺寸（Dh）的聚合物溶液驱替剩余油的机理尚不清楚。利用动态光散射仪测试聚合物溶液的分子线团尺寸。利用哈克流变仪，在相同蠕变时间条件下获得聚合物溶液的蠕变恢复试验数据。利用可视孔隙模型观察不同Dh的聚合物溶液对剩余油的影响。结果表明，聚合物的分子量越高，分子线团尺寸越大。聚合物溶液的弹性特性对分子线团尺寸敏感。随着聚合物分子Dh的增大，弹性部分对聚合物溶液粘度的贡献增加。聚合物的 越高，分子链越长，Dh尺寸越大。在聚合物溶液浓度为2.5 g/L且 不同的条件下，当Dh在320.0 nm至327.8 nm之间时，表观粘度中弹性部分的比例超过粘性部分的比例，这些数据之后的聚合物溶液组成可作为剩余油利用弹性对比研究。在可视孔隙模型中，孔喉比为3.5，水驱采收率为54.26%，Dh = 159.7 nm的聚合物溶液采收率为75.28%，采收率增幅比水驱提高21.02%。随着Dh增大到327.8 nm，实验聚合物溶液的最终采收率为97.82%，聚合物溶液采收率增幅比水驱提高43.56%。然而，在孔喉比为7.0的模型中，相同Dh = 327.8 nm的聚合物溶液采收率增幅仅比水驱高10.44%。相同Dh的聚合物溶液效果随孔喉比增大而变差。
