Thermal Stability of Scleroglucan at Realistic Reservoir Conditions

Thermal stabilities of scleroglucan and two xanthans were determined at 93, 100, and 105°C with and without additives. Aging times varied from 280 to 720 days. The polymers were dissolved in 30,000 ppm TDS seawater with an adjusted pH from 4.5 to 7.5.

Scleroglucan exhibited excellent thermal stability. Under certain test conditions, it lost little or no viscosity at 100°C over 720 days, and only 10 to 20 percent of the original viscosity at 105°C for over 460 days. In contrast to scleroglucan the xanthans were less stable. Depending on the source of the xanthan and the test conditions, viscosity losses varied from 10 to over 90 percent. The triple helix structure of scleroglucan may be responsible for its superior thermal stability.