1. n. [Drilling Fluids]

A chemical system that resists a change in pH. It comprises three components: water, weak acid (or weak base) and salt of the weak acid (or salt of weak base). In a buffered system, the concentration of H⁺ and OH^– ions remain relatively constant because they are in equilibrium with one or more of the other two components, even with the addition of acids or bases.

See: buffer solution,  buffered mud,  hydrolysis,  pH test,  phosphate salt,  total hardness test

2. n. [Well Workover and Intervention]

A chemical used to adjust and control the pH of stimulation fluids. Gels and complex polymer fluids are sensitive to pH changes, especially during the mixing phase when the dispersion and hydration of some polymers require specific pH conditions. In addition, the performance of crosslinked fluids is optimized over a relatively narrow pH range. Buffers, added to the aqueous phase before mixing, adjust the base-fluid pH to achieve a stable treatment fluid with the desired characteristics and predictable performance.

See: gel