Abstract: Fluid loss control for aqueous chemical washes of the type used in well cementing is provided by incorporating in the wash, an effective amount of an oil-soluble resin mixture comprising a particulate friable resin and a particulate pliable resin.

Abstract: Fluid loss control for aqueous chemical washes of the type used in well cementing is provided by incorporating in the wash, an effective amount of the oil-soluble resin mixture described in U.S. Pat. No. 3,891,566.

Abstract: In cementing a well with a thixotropic cement, such as with the portland cement/CaSO.sub.4.1/2H.sub.2 O/water slurry described in U.S. Pat. No. 3,563,313, an effective means for controlling fluid loss from the slurry is to precede the slurry with a fluid comprising water, a water soluble alkali metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel, and a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to the fluid. Optionally, the fluid may contain one or more of: a chelating agent for polyvalent metal cations; a weighing material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales, e.g., those having a high clay content.