β-cyclodextrin assists salt-resistance polymer flooding: Injectivity improvement

• Main Author: Shengwang Yuan
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2020-09-01
• Series: Petroleum
• Subjects: Salt-resistance polymer solutions; Adaptability; β-cyclodextrin; Heterogeneity
• Online Access: http://www.sciencedirect.com/science/article/pii/S2405656119301257

Polymer flooding method has attracted wide attentions in petroleum industry because of its relatively simple process equipment, low cost of agents and good performance on enhancing oil recovery. However, common polymer can hardly meet the technical requirements of the oilfields with high salinity. Existing salt-resistance polymer solutions get a large viscosity in high salinity condition by changing polymer molecules aggregation which, however, may result in the poor adaptability between polymer molecules and the pore sizes of reservoir. β-cyclodextrin (β-CD), a kind of chemical agent, is found to enhance the injectivity of salt-resistance polymer solutions by wrapping the hydrophobic groupings of salt-resistance polymer molecules. For a certain reservoir, the addition of β-cyclodextrin into salt-resistance polymer solution can balance the effect of plugging the layers with high permeability and the purpose of diverting to the layers with low and medium permeability. In this paper, viscosity of polymer solution is tested in condition of different concentrations of β-CD. On that basis, experiments on seepage characteristics are carried out to evaluate the injectivity of salt-resistance polymer solution. Finally, an appropriate concentration of β-CD, which is added into salt-resistance polymer solution, is chosen to adapt a certain reservoir with heterogeneity.