Abstract: Provided herein are defoaming agents that comprise lecithin and a solvent. Optionally, they may comprise hydrophobic particles. One embodiment provides a method comprising: providing a well fluid that comprises foam; providing a defoaming agent that comprises lecithin and a solvent; and contacting the well fluid with the defoaming agent so that the amount of foam present in the well fluid is reduced.

Abstract: Compositions for performing cementing operations in a subterranean zone under high temperature conditions have a density of less than about 10.5 pounds per gallon, and include calcium aluminate, water, and a lightweight additive having a specific gravity of less than about 0.70.

Abstract: Methods for performing cementing operations in a subterranean zone under high temperature conditions include forming a cementing composition having a density of less than about 10.5 pounds per gallon, pumping the cementing composition into the subterranean zone by way of the well bore and allowing the cementing composition to set therein. The cementing composition includes calcium aluminate, water, and a lightweight additive having a specific gravity of less than about 0.70.

Abstract: A fluid loss control additive comprising a crosslinked polymer and sugar and cement compositions comprising the same. In one embodiment, the fluid loss control additive comprises a polymer and a sugar connected by a pH-sensitive crosslink. In some embodiments, the polymer is a polyvinyl alcohol, and the sugar is a sugar alcohol such as sorbitol.

Abstract: Density-reducing additives comprising low-density particulates, and cement compositions comprising such additives, are provided. In one embodiment, the present invention provides a cement composition comprising: a cement component; a density-reducing additive comprising particulates that comprise an agglomerating material; and a base fluid.

Abstract: Methods of using density-reducing additives comprising low-density particulates in subterranean cementing operations are provided. In one embodiment, the present invention provides a method of cementing comprising: providing a cement composition comprising a cement component, a base fluid, and a density-reducing additive comprising particulates that comprise an agglomerating material; placing the cement composition in a location to be cemented; and allowing the cement composition to set therein.

Abstract: A method of cementing in a subterranean formation that comprises providing a foamed cement composition that comprises water, a cement, a gas, and an additive, the additive comprising an anionic foaming agent and at least one of an anionic foam stabilizer or a Zwitterionic foam booster; placing the cement composition into the subterranean formation; and allowing the cement composition to set therein is provided. Foamed cement compositions, additives for foaming and stabilizing a cement composition, and methods of reducing the density of a cement composition, also are provided.

Abstract: Cement compositions including environmentally compatible defoamers and methods of using such cement compositions are provided herein. An example of a method is a method of cementing in a subterranean formation. Another example of a method is a method of reducing foam generation in a cement composition. An example of a composition is a cement composition including water, hydraulic cement, and a defoamer. Another example of a composition is a defoamer.

Abstract: The present invention provides a method and treatment fluid for blocking the permeability of an elevated-temperature zone in a reservoir of a subterranean formation penetrated by a wellbore, the method comprising the steps of: a) selecting the zone to be treated, wherein the upper limit of the temperature range of the zone is equal to or greater than 190° F. (88° C.); b) forming a well treatment fluid comprising: water; a water-soluble polymer comprising polymerized vinyl amine units; and an organic compound capable of crosslinking with the vinyl amine units of the water-soluble polymer; c) selecting the water-soluble polymer and the organic compound of the well treatment fluid such that the gel time of the well treatment fluid is at least 2 hours when measured at the upper limit of the temperature range of the zone; and d) injecting the well treatment fluid through the wellbore and into the zone.

Abstract: The present invention relates to cementing operations, and more particularly to improved cement dispersants for cement compositions and methods of cementing. In one embodiment, the present invention provides a method of cementing comprising the steps of: providing a cement composition comprising a cement, and a dispersant composition, the dispersant composition comprising a surfactant and a hydrolyzed protein; placing the cement composition in a desired location; and allowing the cement composition to set.