BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Cycle (Circulation) Time, Fluid – The time of a cycle, or down the hole and back to the surface is
the time required in minutes for the pump to move the drilling fluid in the hole back to the pump. The
time cycle equals the barrels of fluid in the total circulating system divided by barrels per minute
pump output.
Cyclone - A device for the separation of various particles from a drilling fluid, most commonly used
as a desander. The fluid is pumped tangentially into a cone, and the fluid rotation provides enough
centrifugal force to separate particles by mass weight. See Centrifuge.
Cuttings Bed - The collection of drill cuttings in a particular location due to a lack of carrying
capacity of the drilling fluid as a result of diminished fluid velocity. This particular phenomenon is a
characteristic of horizontal hole drilling where the cuttings tend to settle and collect in beds on the
bottom side of the hole where the fluid velocity is at a minimum.
Darcy - A unit of permeability. A porous medium has a permeability of 1 Darcy when a pressure of
1 atm on a sample 1 cm long and 1 sq cm in cross section will force a liquid of l-cp viscosity through
the sample at the rate of 1 cc/sec.
Deflocculant - A thinning agent used to reduce viscosity or prevent flocculation; sometimes
incorrectly called a “dispersant.” Most deflocculants are low-molecular weight anionic polymers
that neutralize positive charges on clay edges.
Deflocculation - Breakup of flocs of gel structures by use of a thinner.
Defoamer or Defoaming Agent - Any substance used to reduce or eliminate foam by reducing the
surface tension. Compare Antifoam.
Dehydration - Removal of free or combined water from a compound.
Diesel-Oil Plug - See Gunk Plug.
Deliquescence - The liquefaction of a solid substance due to the solution of the solid by adsorption of
moisture from the air, e.g., calcium chloride. The term deliquescence is often used interchangeably
with the term hydroscopic.
Density - Matter measured as mass per unit volume expressed in pounds per gallon (lb m /gal), grams
per cubic centimeter, and pounds per cubic ft (lb m /cu. ft). Density is commonly referred to as
"weight."
Desander - See Cyclone.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-13