2. . 
Saline liquid usually used in completion operations and, increasingly, when penetrating a pay zone. Brines are preferred because they have higher densities than fresh water but lack solid particles that might damage producible formations. Classes of brines include chloride brines (calcium and sodium), bromides, and formates.
3. . 
A general term that refers to various salts and salt mixtures dissolved in an aqueous solution. Brine can be used more strictly, however, to refer to solutions of sodium chloride. We prefer to use brine as a general term. The emulsified calcium chloride [CaCl2] solution (or any other saline phase) in an oil mud is referred to as "brine" or "brine phase." The oil/brine ratio, abbreviated OBR, is used to compare solids content and salinities of oil muds. Clear brines are salt solutions that have few or no suspended solids.
Synonyms: clear brine
See: balanced-activity oil mud, bromide brine, calcium bromide, calcium carbonate, calcium chloride, carboxymethyl hydroxyethylcellulose, cesium acetate, drill-in fluid, formate, guar gum, hydrometer, hydroxyethylcellulose, hydroxypropyl starch, PVT, synthetic/brine ratio, undersaturated fluid
4. . 
A water-based solution of inorganic salts used as a well-control fluid during the completion and workover phases of well operations. Brines are solids free, containing no particles that might plug or damage a producing formation. In addition, the salts in brine can inhibit undesirable formation reactions such as clay swelling. Brines are typically formulated and prepared for specific conditions, with a range of salts available to achieve densities ranging from 8.4 to over 20 lbm/galUS (ppg) [1.0 to 2.4 g/cm3]. Common salts used in the preparation of simple brine systems include sodium chloride, calcium chloride, and potassium chloride. More complex brine systems may contain zinc, bromide, or iodine salts. These brines are generally corrosive and costly.
See: producing formation
5. . 
Water containing salts in solution, such as sodium, calcium, or bromides. Brine is commonly produced along with oil. The disposal of oilfield brine is usually accomplished by underground injection into saltwater-saturated formations or by evaporation in surface pits.