1. adj. [Drilling Fluids]

Pertaining to an aqueous solution, such as a water-base drilling fluid, which has more hydrogen ions (H⁺) than hydroxyl ions (OH^–) and pH less than 7.

Antonyms: alkaline

See related terms: acidity

2. n. [Well Workover and Intervention]

A generic term used to describe a treatment fluid typically comprising hydrochloric acid and a blend of acid additives. Acid treatments are commonly designed to include a range of acid types or blends, such as acetic, formic, hydrochloric, hydrofluoric, and fluoroboric acids. Applications for the various acid types or blends are based on the reaction characteristics of the prepared treatment fluid.

See related terms: acetic acid,  acidity,  formic acid,  hydrofluoric acid