BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Fluid Flow - The state of fluid dynamics of a fluid in motion is determined by the type of fluid (e.g.,
Newtonian plastic, pseudoplastic, dilatant), the properties of the fluid such as viscosity and density,
under a given set of conditions and fluid properties, the fluid flow can be described as plug flow,
laminar (called also Newtonian, streamline, parallel, or viscous) flow, or turbulent flow. See above
terms and Reynolds Number.
Fluidity - The reciprocal of viscosity. The measure of rate with which a fluid is continuously
deformed by a shearing stress. Ease of flowing.
Fluid Loss - Measure of the relative amount of fluid lost (filtrate) through permeable formations or
membranes when the drilling fluid is subjected to a pressure differential. For standard API filtration
test procedure, see API RP 13B.
Fluorescence - Instantaneous re-emission of light, of a greater wave length, than that light originally
absorbed.
Foam - Foam is a two-phase system, similar to an emulsion, where the dispersed phase is a gas or air.
Foaming Agent - A substance that produces fairly stable bubbles at the air-liquid interface due to
agitation, In air or gas drilling, foaming agents are added to turn water influx into aerated foam. This
is commonly called "mist drilling."
Formation Damage - Damage to the productivity of a well resulting from invasion into the
formation by fluid particles or fluid filtrate. Asphalt from crude oil will also damage some
formations. See Mudding Off.
Formation Sensitivity - The tendency of certain producing formations to adversely react with
invading fluid filtrates.
Functions of Drilling Fluids - The most important function of drilling fluids in rotary drilling is to
bring cuttings from the bottom of the hole to the surface. Some other important functions are - control
subsurface pressures, cool and lubricate the bit and drill string, deposition of an impermeable wall
cake, etc.
Funnel Viscosity - See Marsh Funnel Viscosity,
Galena - Lead sulfide (PbS). Technical grades (specific gravity about 7) are used for increasing the
density of drilling fluids to points impractical or impossible with barite.
Garrett Gas Train - An instrument used for quantitative analysis of sulfides and carbonates.
Specific test methods have been published by API. The oil-mud procedure analyzes active sulfides
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-19