Page 317 - Shale Shakers Drilling Fluid Systems

GLOSSARY 299

Flocculating Agent Substances (e.g., most electrolytes, a few polysaccharides, certain natu-
ral or synthetic polymers) that cause the thickening of a drilling fluid.
In Bingham Plastic fluids, the yield point and gel strength increase with
flocculation.

Flocculation (1) Loose association of particles in lightly bonded groups, sometimes
called "floes," with non-parallel association of clay platelets. In concen-
trated suspensions, such as drilling fluids, flocculation results in gelation.
In some drilling fluids, flocculation may be followed by irreversible pre-
cipitation of colloids and certain other substances from the fluid (e.g., red
beds, polymer flocculation). (2) A process in which dissimilar electrical
charges on clay platelets are attracted to each other. This increases the
yield point and gel strength of a slurry.

Flooding (1) The effect created when a screen, hydrocyclone, or centrifuge is fed
beyond its capacity. (2) Flooding may also occur on a screen as a result
of blinding.

Flow Capacity The rate at which a shaker can process drilling fluid and solids. This
depends on many variables including shaker configuration, design and
motion, drilling fluid rheology, solids loading, and blinding by near-size
particles. See: Feed Capacity.

Flow Line The pipe (usually) or trough that conveys drilling fluid from the rotary nipple
to the solids separation section of the drilling fluid tanks on a drilling rig.

Flow Rate The volume of liquid or slurry moved through a pipe in one unit of time
(i.e., gallons per minute, barrels per minute, etc.). See: Circulation Rate.

Flow Streams With respect to centrifugal separators, all liquids and slurries entering and
leaving a machine, such as feed drilling fluid stream plus dilution stream
equals overflow stream plus underflow stream.

Flow-Back Pan A pan or surface below a screen that causes fluid passing through one
screen to flow back to the feed end of a lower screen.

Fluid Any substance that will readily assume the shape of the container in
which it is placed. The term includes both liquids and gases. It is a sub-
stance in which the application of every system of stresses (other than
hydrostatic pressure) will produce a continuously increasing deformation
without any relation between time rate of deformation at any instant and
the magnitude of stresses at the instant.

Fluid Flow The state of dynamics of a fluid in motion as determined by the type of
fluid (e.g., Newtonian plastic, pseudo-plastic, dilatant), the properties
of the fluid such as viscosity and density, the geometry of the system,
and the velocity. Thus, under a given set of conditions and fluid proper-
ties, the fluid flow can be described as plug flow, laminar (also called
Newtonian, streamline, parallel, or viscous) flow, or turbulent flow. See.-
Reynolds Number.

Fluid Loss Measure of the relative amount of fluid loss (filtrate), through permeable
formations or membranes, when the drilling fluid is subjected to a pres-
sure differential. See: Filtrate Loss, API Bulletin RP 13B.

Fluidity The reciprocal of viscosity. The measure of rate with which a fluid is
continuously deformed by a shearing stress. Ease of flowing.