High temperature stable fluid loss control system

摘要

The present invention is directed to a high temperature stable composition capable of imparting fluid loss control properties to aqueous systems. The composition is a combination of: (a) a solid, particulate silicate or alumino-silicate material; (b) a chemical compound capable of converting to a higher oxidation state under alkaline conditions; and (c) a reaction product of a polymeric substance selected from polyvinyl alcohol or hydroxyalkyl cellulose reacted with at least about 0.1 percent of stoichiometry of a cross-linking agent selected from an epihalohydrin or an aldehyde containing or generating agent; wherein the amount of component (a) is at least 50 wt. percent of component (c) and component (b) is at least 20 wt. percent of component (c). The invention is further directed to improved drilling fluids containing said composition and to the process of drilling bore holes using said improved fluid.