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

Abstract

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.

Keywords

Salt-resistance polymer solutions / Adaptability / β-cyclodextrin / Heterogeneity

References

[1] X.L. Jiang, R.J. Wang, X.G. Lu, et al., Experimental study on the reservoir adaptability of polymer molecular weight, Oilfield Chem. 31 (2) (2014) 269-273.

[2] R. Hincapie, C.E. Alvarez, A.J. Vargas, Technical feasibility of polymer injection in heavy oil reservoir BAINF60 and BAMED78:intercampo norte-through predictive models, SPE Heavy Oil Conference and Exhibition, Society of Petroleum Engineers, 2011January.

[3] X.H. Wang, D.K. Han, S.P. Guo, Mechanism and application of polymer flooding, Acta Pet. Sin. 15 (1) (1994) 83-91.

[4] L.L. Guo, Study of polymer's adsorption and retention law and performance change, Chem. Eng. Oil Gas 40 (6) (2011) 587-589.

[5] H. Xu, J.S. Qin, J.L. Wang, et al., 3D physical modeling on macroscopic fluid flow mechanism of enhanced oil recovery by polymer flooding, Pet. Explor. Dev. 34 (03) (2016).

[6] R.B. Cao, P.H. Han, W.H. Hou, et al., Section inversion rules and inversion mechanism of polymer flooding, Acta Pet. Sin. 30 (2) (2009) 267-270.

[7] Y.P. Wang, J.H. Luo, R.Y. Bu, et al., Analysis on polymers of temperature and saltresistant for enhanced oil recovery, Chem. Ind. Eng. Prog. 22 (3) (2003) 271-274.

[8] S.F. Tang, P.Y. Luo, Development of hydrophobically associating water-soluble polymer, Appl. Chem. Ind. 22 (3) (2002) 10-15.

[9] Y.G. Han, Chemicals in heat tolerate and salt resistant flooding, J. Southwest Pet. Univ. (Sci. Technol. Ed.) 33 (3) (2011) 149-153.

[10] X.P. Ma, X.G. Lu, D.F. Zhang, et al., Seepage characteristics and its influencing factors of hydrophobic associating polymer, Pet. Geol. Oilfield Dev. Daqing 34 (3) (2015) 102-107.

[11] X.G. Lu, S.X. Wang, R.J. Wang, et al., Adaptability of a deep profile control agent to reservoirs: taking the Lamadian Oilfield in Daqing as an example, Pet. Explor. Dev. 38 (5) (2011) 2-0.

[12] Y.M. Yu, Molecular Simulation of Cyclodextrin Inclusion, Doctoral dissertation University of Science and Technology of China, 2006.

[13] L. Li, X. Guo, L. Fu, et al., Complexation behavior of α-, β-, and γ-cyclodextrin in modulating and constructing polymer networks, Langmuir 24 (15) (2008) 8290-8296.

[14] J.X. Liu, X.G. Lu, G.Q. Li, et al., Seepage characteristics and mechanism of Cr3+ cross-linked polymer solution in ultra-high salinity media, J. China. Univ. Pet. 37 (6) (2013) 145-152.

[15] L.O. Knobloch, R.E.H. Reina, H. Födisch, L. Ganzer, Qualitative and quantitative evaluation of permeability changes during EOR polymer flooding using micromodels, World J. Eng. Technol. 6 (02) (2018) 332.