The present invention relates to the use of particulate mineral material comprising barite for scavenging heavy metal anions from a liquid medium, wherein the heavy metal anions form water-insoluble barium salts with barium cations of the barite, and wherein the particulate mineral material has a specific surface area of from 0.1 m.sup.2/g to 100 m.sup.2/g, measured using nitrogen sorption and the BET method.

The present invention relates to the use of particulate mineral material comprising barite for scavenging heavy metal anions from a liquid medium, wherein the heavy metal anions form water-insoluble barium salts with barium cations of the barite, and wherein the particulate mineral material has a specific surface area of from 0.1 m.sup.2/g to 100 m.sup.2/g, measured using nitrogen sorption and the BET method.

Methods and systems for the treatment of wells are disclosed. A method for treating a well comprises providing a treatment fluid comprising calcium-aluminate cement, water, and a cement set retarder; and introducing the treatment fluid into a wellbore. A system for treating a well comprises a treatment fluid comprising calcium-aluminate cement, water, and a cement set retarder; a vessel to contain the treatment fluid; a pumping system coupled to the vessel to pump the treatment fluid; and a conduit coupled to the pumping system.

The invention relates to an additive which can be used as a hardening accelerator for hydraulically setting compositions, comprising a) at least one polymeric dispersant comprising structural units having anionic or anionogenic groups and structural units having polyether side chains, b) at least one sulfonic acid compound of the formula (I) ##STR00001##
in which A.sup.1 is NH.sub.2, NHMe, NMe.sub.2, N(CH.sub.2—CH.sub.2—OH).sub.2, CH.sub.3, C.sub.2H.sub.5, CH.sub.2—CH.sub.2—OH, phenyl, or p-CH.sub.3-phenyl and K.sup.n+ is an alkali metal cation, or one equivalent of a cation selected from Ca.sup.2+, Mg.sup.2+, Sr.sup.2+, Ba.sup.2+, Zn.sup.2+, Fe.sup.2+, Fe.sup.3+, Al.sup.3+, Mn.sup.2+, or Cu.sup.2+, and c) calcium silicate hydrate particles.

A method of reducing corrosion in tubular strings installed in wellbores includes dispensing an accelerated cement composition into a wellbore annulus, a casing-casing annulus, or both, the accelerated cement composition comprising a cement composition and an accelerant composition, where: the cement composition comprises a cement precursor and water; the accelerant composition comprises triethanolamine; and a concentration of the triethanolamine in the accelerated cement composition is greater than or equal to 10,000 parts per million by weight; allowing the accelerated cement composition to cure in the annulus to form a cured cement, where the triethanolamine reacts with a metal of the tubular string, the reaction forming a protective layer on the surfaces of the tubular string that inhibits dissolution of iron from the metal of the tubular string.

Calcium silicate-based cements and concretes are disclosed, which result in concrete compositions that have an improved strength development. A cement product includes a plurality of particles of a carbonatable calcium silicate cement and a first additive; wherein, the first additive is an organic molecule with at least one primary, secondary or tertiary amine group.

Disclosed herein are methods for producing an ultra-dense and ultra-smooth ceramic coating. A method includes feeding a solution comprising a metal precursor into a plasma sprayer. The plasma sprayer generates a stream toward an article, forming a ceramic coating on the article upon contact.

Methods of using extended-life cement compositions are disclosed. A method comprises providing an extended-life cement composition comprising calcium-aluminate cement, water, and a cement set retarder. The method additionally comprises mixing the extended-life cement composition with a cement set activator to activate the extended-life cement composition. The method further comprises Introducing the activated extended-life cement composition into a subterranean formation and allowing the activated extended-life cement composition to set in the subterranean formation; wherein the activated extended-life cement composition has a thickening time of greater than about two hours.

Methods of using extended-life cement compositions are disclosed. A method comprises providing an extended-life cement composition comprising calcium-aluminate cement, water, and a cement set retarder. The method additionally comprises mixing the extended-life cement composition with a cement set activator to activate the extended-life cement composition. The method further comprises Introducing the activated extended-life cement composition into a subterranean formation and allowing the activated extended-life cement composition to set in the subterranean formation; wherein the activated extended-life cement composition has a thickening time of greater than about two hours.

Mineral particles may provide for wellbore fluids with tailorable properties and capabilities. In some instances, a dry wellbore additive may comprise a plurality of first mineral particles having a specific gravity of about 2.6 to about 20; a plurality of second mineral particles having a specific gravity of about 5.5 to about 20; a plurality of lubricant particles having a specific gravity of about 2.6 to about 20; wherein the first mineral particles, the second mineral particles, and the lubricant particles are different; and wherein the first mineral particles, the second mineral particles, and the lubricant particles have a multiparticle specific gravity of about 3 to about 20.