Abstract: Wellbore fluids may contain an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide. Methods of using wellbore fluids may include drilling a subterranean well while circulating a wellbore fluid into the subterranean well, wherein the wellbore fluid contains an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide.

Abstract: Wellbore fluids may contain an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide. Methods of using wellbore fluids may include drilling a subterranean well while circulating a wellbore fluid into the subterranean well, wherein the wellbore fluid contains an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide.

Abstract: Branched and crosslinked polymeric fluid loss control agents and methods are provided that have at least one acrylamide-based monomer, at least one sulfonated anionic monomer, and at least one crosslinking monomer. The at least one acrylamide-based monomer and the at least one sulfonated anionic monomer are crosslinked. The branched and crosslinked polymeric fluid loss control agents have between 50 and 99 mol % of the at least one acrylamide-based monomer, between 1 and 30 mol % of the at least one sulfonated anionic monomer, and between 0.1 and 10 mol % of the at least one crosslinking monomer.

Abstract: Wellbore fluids may contain an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide. Methods of using wellbore fluids may include drilling a subterranean well while circulating a wellbore fluid into the subterranean well, wherein the wellbore fluid contains an aqueous base fluid comprising a monovalent brine, a modified starch, and a metal oxide.

Abstract: Methods of breaking a filter cake in a wellbore may include circulating a breaker fluid into the wellbore, the breaker fluid having a (2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) chelant, where the HEDTA chelant is used with divalent brine in the breaker fluid or in the filter cake.

Abstract: A method may include circulating a breaker fluid into a wellbore, where the breaker fluid includes a base fluid of divalent brine having an amount of free water therein; a primary breaker; and a secondary breaker present in an amount less than the primary breaker, where the primary breaker is either a hydrolysable ester of a carboxylic acid or an iminodiacetic acid, and the secondary breaker is the other of the hydrolysable ester of a carboxylic acid or an iminodiacetic acid.

Abstract: Methods may include circulating a breaker fluid into a wellbore, the breaker fluid containing: a base fluid, a peroxide source, and a catalyst. In another aspect, methods may include drilling a wellbore with a drilling fluid containing a catalyst, and circulating a breaker fluid into a wellbore, the breaker fluid containing a base fluid, and a peroxide source. In yet another aspect, methods may include treating a contaminated fluid with a treatment fluid containing a base fluid, a peroxide source, and a catalyst.

Abstract: A wellbore fluid for dissolving a filtercake includes a chelating agent and an aqueous solution of carboxylate salt. The concentration of the chelating agent is up to 50 percent volume per volume (v/v) in the aqueous solution of carboxylate salt. A method of treating a well includes preparing a wellbore fluid up to 50 percent volume per volume (v/v) chelating agent in an aqueous solution of carboxylate salt. The method further includes emplacing the wellbore fluid downhole such that the wellbore fluid dissolves a filtercake in the well.