Drilling mud, also called drilling fluid, is a lubricant used while drilling oil and natural gas wells. An oil well is a laymans term for any perforation through the Earths surface designed to find and release both petroleum oil and gas hydrocarbons. ... Natural gas (commonly refered to as gas in many countries, but note that gas is also an American and Canadian shortening of gasoline) is a gaseous fossil fuel consisting primarily of methane. ...

Purpose

The two primary purposes of drilling mud or drilling fluids are to:

1. Remove cuttings from the formation produced by the bit at the bottom of the hole and carry them to the surface. This is achieved by adjusting the rheology of the mud system.
2. Maintain hydrostatic equilibrium so that fluids and gas from the formation do not enter the well bore causing the well to flow, kick or blow out. This is achieved by adjusting the mud weight (density). High-density additives (barite, hematite) are used for preparation of kill-weight fluids, which create hydrostatic pressure that prevents water entering the well or hold the oil/gas inside and prevent blowout, and to physically stabilize the formation.

Rheology is the study of the deformation and flow of matter. ... Hydrostatic pressure is the pressure exerted by a fluid due to its weight. ... Equilibrium or balance is any of a number of related phenomena in the natural and social sciences. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... Blowouts are sandy depressions caused by removal of material by wind. ...

Details of usage

On a drilling rig pumping it with mud pumps through the drill string where it sprays out of nozzles on the drill bit, the mud then travels back up the annular space between the drill string and the sides of the hole being drilled, up through the surface casing, and emerges at the surface. Cuttings are then filtered out at the shale shaker and the mud enters the mud pits. The mud is then pumped back down and is continuously recirculated and periodicaly treated to give it properties that optimize and improve drilling efficiency. Natural gas drilling rig A drilling rig or oil rig is a structure housing equipment used to drill for and extract oil or natural gas from underground reservoirs. ... In petroleum drilling technology, a drill string in an oil rig is the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly or top drive to the drill collars and bit. ... Drill bits are the cutters of drill tools. ...

Composition of drilling mud

Drilling mud may consist of bentonite clay with additives such as barium sulfate or hematite. Various thickeners are used to influence the viscosity of the fluid, eg. guar gum, glycol, carboxymethylcellulose, or starch. In turn, deflocculents are used to reduce viscosity of clay-based muds; anionic polyelectrolytes (eg. acrylates, polyphosphates, lignosulfonates or tannic acid derivates (eg. Quebracho) are frequently used. Red mud was the name for a Quebracho-based mixture, named after the color of the red tannic acid salts; it was commonly used in 1940s to 1950s, then was obsoleted when lignosulfates became available. Bentonite - USGS Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite, (Na,Ca)0. ... Quaternary clay in Estonia. ... Barium sulfate (or barium sulphate), chemical formula BaSO4, is an ionic compound and is essentially insoluble in water. ... Hematite (AE) or haematite (BE) is the mineral form of Iron (III) oxide, (Fe2O3), one of several iron oxides. ... Thickening agents, or thickeners, are substances which, when added to the mixture, increase its viscosity without substantially modifying its other properties, like eg. ... The pitch drop experiment at the University of Queensland. ... Guar gum is an edible thickening agent extracted from the guar bean (Cyamopsis tetragonoloba). ... Ethylene glycol (IUPAC name:ethane-1,2-diol) is a chemical compound widely used as an automotive antifreeze (coolant). ... Carboxymethyl cellulose, or CMC, is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. ... Starch is a complex carbohydrate which is insoluble in water. ... A thinning agent used to reduce viscosity or prevent flocculation; incorrectly called a dispersant. ... Polyelectrolytes combine the properties of electrolytes (salts) and polymers (high MW compounds). ... Acrylate monomers are esters that contain vinyl groups, that is, two carbon atoms double bonded to each other, directly attached to the carbonyl carbon. ... Polyphosphates are phosphate polymers linked between hydroxyl groups and hydrogen atoms. ... Lignosulfonates, or sulfonated lignin, are water-soluble anionic polyelectrolyte polymers, byproducts of the Kraft process and sulfite process for production of wood pulp. ... Tannic acid, a commercial form of tannin is not a true acid but an acid-like substance called a polyphenol. ... Quebracho is one of the common names, in Spanish, of at least three similar species of trees that grow in the Gran Chaco region of South America: Schinopsis lorentzii (quebracho colorado santiagueño), of the family Anacardiaceae; Schinopsis balansae (quebracho colorado chaqueño), of the same family; Aspidosperma quebracho-blanco... Quebracho is one of the common names, in Spanish, of at least three similar species of trees that grow in the Gran Chaco region of South America: Schinopsis lorentzii (quebracho colorado santiagueño), of the family Anacardiaceae; Schinopsis balansae (quebracho colorado chaqueño), of the same family; Aspidosperma quebracho-blanco...

One classification scheme for drilling fluids is based on their composition, and divides them to

• water-base,
• non-water base, and
• gaseous, or pneumatic.

Mud engineer

The slang name given to an oil field service company individual who is charged with maintaining a drilling fluid or completion fluid system on an oil and or gas drilling rig. The work schedule of the mud engineer or Drilling Fluid Engineer as he or she is more properly called these days is usually fairly strenuous, as are most jobs in this industry. Until a few years ago, the "mud engineer" rarely worked a set schedule and, if resident on an offshore installation, may have been on call for 24 hours a day. With the advent some 15 years ago in Northern Europe, of having two mud engineers offshore due to Health, Safety and Environmental regulations and working hours restrictions in more advanced countries, the mud engineer rarely works more than the normal 12 hour shift. On land however there still may be only one mud engineer and he may be allocated to more than one drilling rig, spending a greater part of the day, driving from rig to rig, testing the drilling or completion fluids, make a recomendation as the maintenance, before going off to another rig. Offshore drilling, with new technology and high total day costs for the operation, have wells being drilled extremely fast and day rates for operations have increased. Any down time is frowned upon and two mud engineers makes economical sense, to sensible oil companies, to prevent down time due to drilling fluid difficulties. Two Mud Engineers also reduce insurance loading to oil companies for possible environmental damage that oil companies are responsible for during their license to drill and produce.

The cost of the drilling fluid is typically about 10% of the total cost of well construction. This large cost overhead places a demand on the competency of the mud engineer. Large cost savings can result when the mud engineer adequately performs his job.

Not to be confused with service personnel charged with monitoring gas from the mud and collecting wellbore samples is known as a mud logger. This article needs to be cleaned up to conform to a higher standard of quality. ...