George M. Holzwarth - Linden NJ
Lars A. Naslund - Morganville NJ
Erik I. Sandvik - Houston TX
Exxon Research & Engineering Co. - Florham Park NJ
A process for recovering crude oil from a subterranean formation using aqueous saline heteropolysaccharide solutions containing at least 0. 5 wt. % of inorganic salts which are stabilized against viscosity loss on heat treatment. The stabilization process comprises preparing an aqueous solution containing heteropolysaccharide and inorganic salts, removing oxygen from the saline solution, heating to a temperature of at least 100. degree. C. in an inert atmosphere, then removing cell debris. The solutions also have improved filterability and are free of cell debris.