Description
Circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface. Other functions are to cool the bit and counteract downhole formation pressure. While a mixture of barite, clay,water, and chemical additives is the most common drilling fluid, wells could also be drilled using the air, gas,water, or oil-base mud as the drilling fluid. See mud.
Source :
Alpha Thames Ltd 2004