In the

oil industry The petroleum industry, also known as the oil industry, includes the global processes of exploration, extraction, refining, transportation (often by oil tankers and pipelines), and marketing of petroleum products. The largest volume products ...

, mud weight is the density of the

drilling fluid In geotechnical engineering, drilling fluid, also known as drilling mud, is used to aid the drilling of boreholes into the earth. Used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also use ...

and is normally measured in pounds per gallon (lb/gal) (ppg) or pound cubic feet (pcf) .www.glossary.oilfield.slb.com
/ref> In the field it is measured using a mud scale or mud balance. Mud can weigh up to 22 or 23 ppg. A gallon of water typically weighs 8.33 pounds (or 7.48 ppg). In conventional drilling fluids,

barite Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate (Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

is used to increase the density. Although other additives such as

halite Halite ( ), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...

(salt) or

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

can also be used. Mud weight can be decreased by dilution or solids control equipment such as an industrial

centrifuge A centrifuge is a device that uses centrifugal force to subject a specimen to a specified constant force - for example, to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby ...

, desilter, desander and shale shaker . Mud weight use to control the trapped fluids or gas in the formations by adding a hydro static pressure on them, increasing the mud weight = increasing the hydro static pressure. If the hydro static pressure increased over the formations pressure that will make a fracture in the formation leading to lose the mud to the formation, so adding loss circulation material like gel-flake or wood chips that can refill the gap and stop the mud loss. If the mud loss continues, then the hydro static pressure will decrease and flammable fluids and gas trapped under pressure will start leaking to the surface. This can lead to a potential blowout.

References

Drilling fluid {{Engineering-stub