Drilling fluid

Gaseous drilling fluids, typically utilizing air or natural gas, sometimes with the addition of foaming agents, can be used when downhole conditions permit.

Liquid fluids are composed of natural and synthetic material in a mixed state,[1] which can be of two types:[2] Water-based drilling mud most commonly consists of bentonite clay (gel) with additives such as barium sulfate (baryte) to increase density, and calcium carbonate (chalk) or hematite.

In turn, deflocculants are used to reduce viscosity of clay-based muds; anionic polyelectrolytes (e.g. acrylates, polyphosphates, lignosulfonates (Lig) or tannic acid derivates such as Quebracho) are frequently used.

Because of the risk of a fire or an explosion, special monitoring sensors and explosion-proof certified equipment are commonly installed, and workers are trained in safety precautions.

Its ability to do so depends on cutting size, shape, and density, and speed of fluid traveling up the well (annular velocity).

A Vanity Fair article described the conditions at Lago Agrio, a large oil field in Ecuador where drillers were effectively unregulated.

[8] Water-based drilling fluid has very little toxicity, made from water, bentonite and baryte, all clay from mining operations, usually found in Wyoming and in Lunde, Telemark.

However, when mixed into water-based drilling fluids, hydrochloric acid only decreases the pH of the water to a more manageable level.

Caustic (sodium hydroxide), anhydrous lime, soda ash, bentonite, baryte and polymers are the most common chemicals used in water-based drilling fluids.

[13] This individual typically works for the company selling the chemicals for the job and is specifically trained with those products, though independent mud engineers are still common.

Having two mud engineers makes economic sense to prevent down time due to drilling fluid difficulties.

The compliance engineer is the most common name for a relatively new position in the oil field, emerging around 2002 due to new environmental regulations on synthetic mud in the United States.