Gypsum (Gyp) Muds are water mud system which containing gypsum. Gyp mud can be used for drilling shales, but it is also well-suited for drilling gypsum, anhydrite and salt stringers. An advantage of gyp over lime muds is that the pH of gyp mud need not be so high because it contains more soluble Ca+2 to inhibit shale swelling. Gypsum, CaSO4·2H2O, content is measured by an API test, and more can be added as needed. A calcium tolerant clay deflocculant may be needed to control viscosity. Carboxymethylcellulose (CMC) and starch are used for fluid loss control along with a small amount of prehydrated bentonite.
Water-based drilling fluids, regardless of the name assigned to them, usually contain clays, water soluble chemicals (including salts), a pH control additive (hydroxyl source), and one or more organic polymers, surfactants, and deflocculants.
Spud Mud is used to start the drilling of a well and continues to be used while drilling the first few hundred feet of hole. Spud mud is usually an unweighted water-base mud, made up of water and natural solids from the formation being drilled. It may contain some commercial clay, added to increase viscosity and improve wall-cake building properties.
The Oil & Gas industry uses and generates enormous quantities of this commodity. On average, for every barrel of oil produced there are eight barrels of associated wastewater. Increasing the efficiency of water usage and improving its management is both a high priority among E&P companies and a subject of intense scrutiny for the communities in which they operate.