SPE Reservoir Evaluation & Engineering
Volume 14, Number 6, December 2011, pp. 726-734

SPE-141355-PA

Rheology of a New Sulfonic Associative Polymer in Porous Media

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DOI  More information 10.2118/141355-PA http://dx.doi.org/10.2118/141355-PA

Citation

  • Seright, R.S., Fan, T., Wavrik, K., Wan, H., Gaillard, N., and Favéro, C. 2011. Rheology of a New Sulfonic Associative Polymer in Porous Media. SPE Res Eval & Eng  14 (6): 726-734. SPE-141355-PA. http://dx.doi.org/10.2118/141355-PA.

Discipline Categories

  • 6.4.6 Chemical Flooding Methods Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex)
  • 6.3.1 Flow in Porous Media
  • 6.3.3 Conformance Improvement

Keywords

  • Polymer flooding, Associative polymer, Rheology in porous media

Summary

For hydrophobically associative polymers, incorporating a small fraction of hydrophobic monomer into a hydrolyzed polyacrylamide (HPAM) polymer can promote intermolecular associations and thereby enhance viscosities and resistance factors. In this paper, we investigate the behavior of a new associative polymer in porous media. The tetra-polymer has low hydrophobic-monomer content and a molecular weight (Mw) of 12-17 million g/mol. Total anionic content is 15-25 mol%, including a few percent of a sulfonic monomer. This polymer is compared with a conventional HPAM with 18-20 million g/mol Mw and 35-40% anionic content. Rheological properties (viscosity vs. concentration; and shear rate and elastic and loss moduli vs. frequency) were similar for the two polymers [in a 2.52% total dissolved solids (TDS) brine at 25°C]. For both polymers in cores with permeabilities from 300 to 13,000 md, no face plugging or internal-filter-cake formation was observed, and resistance factors correlated well using the capillary-bundle parameter. For the HPAM polymer in these cores, low-flux resistance factors were consistent with low-shear-rate viscosities. In contrast, over the same permeability range, the associative polymer provided low-flux resistance factors that were two to three times the values expected from viscosities. Moderate shear degradation did not eliminate this effect--nor did flow through a few feet of porous rock. Propagation experiments in long cores (up to 157 cm) suggest that the unexpectedly high resistance factors could propagate deep into a reservoir--thereby providing enhanced displacement compared with conventional HPAM polymers. Compared with HPAM, the new polymer shows a significantly higher level of shear thinning at low fluxes and a lower degree of shear thickening at high fluxes.

© 2011. Society of Petroleum Engineers

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History

  • Original manuscript received: 26 January 2011
  • Meeting paper published: 11 April 2011
  • Revised manuscript received: 18 April 2011
  • Manuscript approved: 2 June 2011
  • Published online: 9 November 2011
  • Version of record: 28 December 2011