BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Neat Cement – A slurry composed of Portland cement and water.
Neutralization - A reaction in which the hydrogen ion of an acid and the hydroxyl ion of a base unite
to form water, the other ionic product being a salt.
Newtonian Flow - See Newtonian Fluid.
Newtonian Fluid - The basic and simplest fluids from the standpoint of viscosity consideration in
which the shear force is directly proportional to the shear rate.. These fluids will immediately
begin-to- move when a pressure or force in excess of zero is applied. Examples of Newtonian fluids
are water, diesel oil, and glycerin. The yield point as determined by direct-indicating viscometer is
zero.
Non-Conductive Fluid - Any drilling fluid, usually oil-base or invert- emulsion fluids, whose
continuous phase does not conduct electricity, e.g., oil. The spontaneous potential (SP) and normal
resistivity cannot be logged, although such other logs as the induction, acoustic velocity, etc., can be
run.
Normal Pressure - The pore pressure of rocks that is considered normal in areas in which the change
in pressure per unit of depth is equivalent to hydrostatic pressure. The normal hydrostatic pressure
gradient for freshwater is 0.433 pounds per square inch per foot (psi/ft), and 0.465 psi/ft for seawater
with 100,000 ppm total dissolved solids (a typical Gulf Coast water).
Normal Solution - A solution of such a concentration that it contains 1 gram-equivalent of a
substance per liter of solution.
Oil Base Mud (OBM) - The term "oil-base mud" is applied to a special type drilling fluid where oil
(usually diesel oil) is the continuous phase and water the dispersed phase. Oil-base muds contain
emulsifiers, wetting agents, viscosifiers, filtration control agents, and water (usually brine)
emulsified into the system. These muds are also referred to as “non-aqueous” fluids as the major, or
continuous phase is not water. These systems may also be formulated from more environmentally
acceptable synthetic oils and are then referred to as “synthetic oil-base muds” (SOBM)
Oil/Brine Ratio - Ratio of the volume percent oil to the volume percent water in an oil mud, where
each is a percent of the total liquid in the mud. OWR is calculated directly from the retort analysis of
an oil mud, but the brine content is calculated from the water content by using the chloride and
calcium titration data. For example, if a mud contains 60 vol.% oil and 20 vol.% brine, the oil
percentage is [60/(60 + 20)]100 = 77% and the water percent is [18/(60 + 18)] = 23%. That OWR is
written as 77/23.
Oil Content - The oil content of any drilling fluid is the amount of oil in volume-percent.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-33