1. n. [Drilling]
Any relatively small quantity (less than 200 bbl) of a special blend of drilling fluid to accomplish a specific task that the regular drilling fluid cannot perform. Examples include high-viscosity pills to help lift cuttings out of a vertical wellbore, freshwater pills to dissolve encroaching salt formations, pipe-freeing pills to destroy filter cake and relieve differential sticking forces and lost circulation material pills to plug a thief zone.
See related terms: cuttings, differential sticking, drilling fluid, lost-circulation material, thief zone
2. n. [Drilling Fluids]
A small volume of mud used for a specific purpose in a drilling operation. Various types of pills are needed from time to time on the rig, such as to stop circulation loss or free stuck drillpipe.
See related terms: granular lost-circulation material, gunk plug, lost circulation, lost-circulation material, mud, rheology, slug, spotting fluid, viscosity
3. n. [Well Workover and Intervention]
A relatively small volume of specially prepared fluid placed or circulated in the wellbore. Fluid pills are commonly prepared for a variety of special functions, such as a sweep pill prepared at high viscosity to circulate around the wellbore and pick up debris or wellbore fill. In counteracting lost-circulation problems, a lost-circulation pill prepared with flaked or fibrous material is designed to plug the perforations or formation interval losing the fluid.
