Dilute iota- and kappa-Carrageenan solutions with high viscosities in high salinity brines

✍ Scribed by Stefan Iglauer; Yongfu Wu; Patrick Shuler; Yongchun Tang; William A. Goddard III

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 1010 KB
• Volume: 75
• Category: Article
• ISSN: 0920-4105
• DOI: 10.1016/j.petrol.2010.11.025

✦ Synopsis

We evaluated the rheological characteristics of ιand κ-Carrageenan in aqueous solutions. Viscosities strongly increased with increasing polymer concentration or salinity. Monovalent Na + cations were more effective in increasing viscosity than divalent Ca 2+ cations. A more complex brine containing Na + , Mg 2+ and Ca 2+ cations also showed high viscosities at a high salinity. We observed shear thinning behavior for these polysaccharide solutions. We explain these rheological phenomena with molecular processes, specifically the conformation change of the ι-Carrageenan from random coil to double helix. In the context of enhanced oil recovery, ι-Carrageenan solutions can reach much higher viscosities at high salinities than standard polyacrylamide solutions. Moreover, Carrageenans are renewable, nontoxic, green substances.