Drilling fluid Essay Example | Topics and Well Written Essays - 1000 words

Drilling fluid - Essay Example The mud also provides hydrostatic pressure to balance the formation pressure resulting from the formation fluids in the borehole that if uncontrolled might lead to blowout. The mud is also used in transmitting hydraulic horsepower from the surface to the drilling bit and power the measurement and logging while drilling tools. The choice of drilling mud is determined by the drilling operation to be done, and its properties should be such that it prevents back pressure and blow outs within the minimum costs as possible. (Committee, 2004, pp. 15-19) Drilling fluids are classified into three major types like water, oil, and pneumatic based fluids. The three major types are further classified depending on the purpose, chemicals added fluid phases, alkalinity and dispersion. Water based muds have four phases which include water, Active colloidal solids, Inert solids and Chemicals. The water phase or continuous provides the initial viscosity which is modified to achieve the required flow properties. The water phase also suspends the active colloidal solids and the inert solids. A sample of colloidal solid present is the Bentotite, and that of an inert solid is the Berite. Bentonite, which is a clay provides just sufficient viscosity for carrying the fragments to the surface. Baruim Sulfate increases the weight of the column for borehole stabilization. Caustic soda and other ingredients are added to increase the alkalinity and reduce corrosion. Salts such as Potassium chloride are also added to prevent water from infiltrating the rock formation. Clay is added to water based fluids to increase their density, yield point, gel strength, viscosity and to minimize fluid loss. The clays added are classified as Montmorillonites or bentonite, Kaolinites, and Illi tes. The chemicals are also added to improve the flow properties and are listed as Thinners, Dispersants and Deflocculants. (Caenn, 2011, pp. 538-542) Based on the dispersion, water