Abstract: This invention relates to a method of repairing holes, channels, voids and microannuli in a cement sheath situated in the annular space between a casing and the wall of a wellbore penetrating a subterranean earth formation, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in a water slurry, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: This invention relates to a method of terminating the undesirable flow of fluid through a gravel pack in a wellbore, or from a highly permeable portion of or fracture in a subterranean formation into a wellbore, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in either a slurry of water or hydrocarbon liquid, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: Dispersants and fluid loss additives for inclusion in oil field cements and methods of using the resultant compositions in oil, gas and water well cementing operations are disclosed. Such compositions incorporate a polymeric additive prepared by caustic-catalyzed condensation for formaldehyde with acetone, or a substance derived from acetone, wherein said polymer includes sodium sulfonate groups in an amount sufficient to render such polymer water soluble. A second fluid loss additive such as hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, copolymers of N,N-dimethylacrylamide and 2-acrylamido, 2-methyl propane sulfonic acid or copolymers of acrylamide and 2-acrylamido, 2-methyl propane sulfonic acid may optionally be included.