Water based drilling muds

1 Water based drilling muds Darley and Gray, 1998) 

During the drilling of a well, a drilling fluid is a vital component of the drilling process as it serves to  

Suspend the rock cuttings and carry them to the surface. 

Seal the pores of the rock formation in order to prevent the in-flow of oil, water or gas. 

Compensate for the reservoir pressure by means of hydrostatic pressure. 

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Inhibited Muds—Dispersed Systems. These are water-base drilling muds that repress the hydration and dispersion of clays. There are essentially four types of inhibited muds lime muds (high pH), gypsum muds (low pH), seawater muds (unsaturated saltwater muds, low pH), and saturated saltwater muds (low pH). 

Water-based drilling muds that repress hydration of clays (lime muds, gypsum muds, seawater muds, saturated saltwater muds)... 

Such a composition reduces friction, permeates drilling mud wall cake, destroys binding wall cake, and reduces differential pressure. Unfortunately, many of such compositions are toxic to marine life. Synthetic PAOs are nontoxic and effective in marine environments when used as lubricants, retum-of-permeabiUty enhancers, or spotting fluid additives for water-based drilling muds. A continuing need exists for other nontoxic additives for water-based drilling muds, which serve as lubricants, retum-of-permeability enhancers, and spotting fluids. 

V. N. Umutbaev, M. G. Kamaletdinov, B. A. Andreson, R. G. Abdrakhmanov, A. U. Sharipov, and I. V. Utyaganov. Lubricant additive for water-based drilling muds—contains a mixture of phenolic mannich bases, additional phosphoric acid and water. Patent SU 1799895-A, 1993. 

Neff, J.M. (2005) Composition, environmental fates, and biological effects of water based drilling muds... 

Amanullah Md. (2007) Screening and evaluation of some environment friendly mud additives to use in water based drilling muds. SPE-98054 SPE Environmental and Safety Conference,... 

Dodilube Brands. [Hoechst Cdtuiese] Ninogen-containing condensate lubricant fiv water-based drilling muds. 

Hydropur. oechst AG] Acrylamide/ acrylate polymers vise, control agents for water-based drilling muds. 

Neff, J.M. (2005). Composition, environmental fates, and biological effect of water-based drilling muds and cuttings discharged to the marine environment A synthesis and annotated bibliography. Submitted to Petroleum Environmental Research Forum (PERF). ht //perf.org/pdf/APIPERFreport.pdf, last visited 29 June 2012. Non-Black Fillers for Rubber, http //www.rtvanderbilt.com/NonBlackFillers.pdf, last visited 26 June 2012. 

The alkalinity of the fluid is also essential for corrosion control, rheological properties in bentonite mud, and for its reaction with some formation constituents. Water-based drilling mud (Spud Mud) commonly consists of bentonite clay (gel) accounting for around 10% of the mixture, with additives such as barium sulphate (barite), calcium carbonate (chalk) or hematite (e.g., HSL, 2000). In some cases (Natural Bentonite Mud), caustic soda (ca. 1% of the mud mass) is added to water and bentonite (ca. 9% of the mud mass) to stabilize the pH. The pH usually ranges between 9.5 and 10.5, but higher values are not uncommon (e g., Finger and Blankenship, 2010). 

Sifferman TR, Muijs HM, Fanta GF, Felker FC, Erhan SM. 2003. Starch-lubricant compositions for improved lubricity and fluid loss in water-based drilling muds. In SPE 80213, SPE Symposium on Oilfield Chemistry. Richardson, TX Society of Petroleum Engineers, pp. 1-5. 

Gregory, A.R., 1990. Ultras[Pg.468]

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