Viscosified aqueous chitosan-containing well drilling and servicing fluids

摘要

The invention provides well drilling and servicing fluids and method of drilling a well therewith, the fluids comprising an alkaline aqueous liquid containing chitosan and an anhydride therein, and optionally an aldehyde and/or pyruvic acid therein. The preferred anhydride is succinic anhydride at an anhydride to chitosan weight ratio from about 0.1 to 1 to about 1.5 to 1.