Journal of Canadian Petroleum Technology
Volume 49, Number 12, December 2010, pp. 49-56

SPE-133471-PA

Effect of Elasticity During Viscoelastic Polymer Flooding: A Possible Mechanism of Increasing the Sweep Efficiency

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DOI  More information 10.2118/133471-PA http://dx.doi.org/10.2118/133471-PA

Citation

  • Urbissinova, T.S., Trivedi, J., and Kuru, E. 2010. Effect of Elasticity During Viscoelastic Polymer Flooding: A Possible Mechanism of Increasing the Sweep Efficiency. J Can Pet Technol  49 (12): 49–56. SPE-133471-PA. doi: 10.2118/133471-PA.

Discipline Categories

  • 6.4.6 Chemical Flooding Methods Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex)

Keywords

  • polymer flooding, viscoelastic fluids

Summary

It has been long believed that the viscoelasticity of polymer solution improves the displacement efficiency in polymer flood operations, but the individual effect of elasticity has not been clearly distilled for a single viscoelastic polymer. In this study, the effect of elasticity of polymer-based fluids on the microscopic sweep efficiency is investigated by injecting two polymer solutions with similar shear viscosity, but significantly different elastic characteristics.

Blends of various grades of polyethylene oxide (PEO) with similar average molecular weight and different molecular weight distribution (MWD) were prepared by dissolving in deionized water. The polymer solutions exhibited identical shear viscosity, but different elasticity. A series of experiments were performed by injecting the polymer solutions through a sandpack saturated with mineral oil. The experiments were performed using a special core holder designed to simulate radial flow. Injection was done through a perforated injection line located at the centre of the cell and fluids were produced through two production lines located at the periphery. The experiments were conducted within a shear rate range of field applications. Because both polymer solutions had similar shear viscosity behaviour, but different elastic properties, it was possible to see the effect of elasticity on the sweep efficiency alone.

Results of the polymer flooding experiments indicated that the sweep efficiency of a polymeric fluid could be effectively improved by adjusting the MWD of the solution at constant shear viscosity and polymer concentration. The polymer solution with higher elasticity exhibited considerably higher resistance to flow through porous media than the one with lower elasticity, resulting in higher sweep efficiency and lower residual oil saturation.

© 2010. Society of Petroleum Engineers

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History

  • Original manuscript received: 29 March 2010
  • Meeting paper published: 26 May 2010
  • Revised manuscript received: 22 September 2010
  • Manuscript approved: 30 September 2010
  • Published online: 1 December 2010
  • Version of record: 1 December 2010