BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Micron (µ) = MU - A unit of length equal to one millionth part of a meter, or one thousandth part of
a millimeter.
Millidarcy - 1/l000 Darcy. See Darcy.
mL or Milliliter - A metric system unit for the measure of volume. Literally 1/1000th of a liter. In
drilling fluid analysis work, this term is used interchangeably with cubic centimeter (cc). One quart is
about equal to 946 mL.
Mist Drilling - A method of Rotary drilling whereby water and/or oil is dispersed in air and/or gas as
the drilling fluid.
Mixed-Metal Hydroxide (MMH) - A compound containing hydroxide anions in association with
two or more metal cations. MMH particles are extremely small and carry multiple positive charges.
They can associate with bentonite to form a strong complex that exhibits highly shear-thinning
properties, with high and fragile gel strengths, high yield point (YP), and low plastic viscosity (PV).
MMH muds are used as nondamaging drilling fluids, metal-reaming fluids (to carry out metal
cuttings) and for wellbore shale control. Being anionic, MMH mud is sensitive to anionic
deflocculants and small anionic polymers, such as polyphosphates, lignosulfonate or lignite.
Molecular Weight - The sum of the atomic weights of all the constituent atoms in the molecule of an
element or compound.
Molecule - When atoms combine, they form a molecule. In the case of an element or a compound, a
molecule is the smallest unit which chemically still retains the properties of the substance in mass.
Monkeyboard - The small platform that the derrickman stands on when tripping pipe.
Montmorillonite - A clay mineral commonly used as an additive to drilling fluids. Sodium
montmorillonite is the main constituent in bentonite. The structure of montmorillonite is
characterized by a form which consists of a thin platey-type sheet with the width and breadth
indefinite, and thickness that of the molecule. The unit thickness of the molecule consists of three
layers. Attached to the surface are ions that are replaceable. Calcium montmorillonite is the main
constituent in low-yield clays.
Mud - A water- or oil-base drilling fluid whose properties have been altered by solids, commercial
and/or native, dissolved and/or suspended. Used for circulating out cuttings and many other
functions while drilling a well. Mud is the term most commonly given to drilling fluids. See Drilling
Fluids.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-31