The Dow Chemical Company

James R Sharpe

Dustin L Free

Oliver W Crinkelmeyer

Roland L Root

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.

Chemical wash with fluid loss control

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.

Method for treating a well using a chemical wash with fluid loss control

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.

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Houston, TX, United States of America

James R Sharpe