Gel kinetic characteristics and creep behavior of polymer microspheres based on bulk gel

Abstract

Deep profile control technology of polymer microspheres has become a widely used new method in improving oil recovery in heterogeneous reservoirs. The viscoelastic property of polymer microspheres plays an important role in the deformable migration behavior. In this study, a new method of measuring the viscoelastic properties of polymer microspheres based on bulk gel was proposed. Using mechanical rheometer and microrheometer, the effects on the storage modulus and gel performance were systematically researched. The creep-recovery test was applied to characterize the creep behavior of different polymer microsphere bulk gel. The results show that the storage modulus of polymer microspheres could be controlled by adjusting the agent concentration in the synthetic reaction. Moreover, the kinetic equation of gel time of polymer microspheres bulk gel and reaction temperature was established: ln(GT) = 3289.18(1/T)-9.33. Elastic strain index was put forward as a new parameter to characterize the viscoelasticity of polymer microsphere in creep-recovery test. Finally, relationship between elastic strain index and storage modulus was constructed and a classification criterion of polymer microspheres with different viscoelasticity was proposed based on a large number of creep-recovery results. The research could provide a good theoretical guidance and technical support for the understanding of viscoelasticity of polymer microspheres.

Graphical Abstract

Keywords:

• Bulk gel
• creep behavior
• elastic strain index
• polymer microspheres
• storage modulus

Acknowledgments

The work was supported by the China Postdoctoral Science Foundation (2017M612378), Shandong Provincial Natural Science Foundation, China (ZR2017LEE001), the National Natural Science Foundation of China (51774309), the Fundamental Research Funds for the Central Universities (16CX06032A, 15CX08003A), Scientific Research Fund for Introducing Scholars of China University of Petroleum (YJ201601088) and Qingdao Postdoctoral Application Research Project (2016222).

Conflict of interest

The authors declare that they have no conflict of interest.