Page 337 - Shale Shakers Drilling Fluid Systems

GLOSSARY 319

pseudoplastic fluid is guar gum in fresh or saltwater. See: Viscosity,
Bingham Model, Plastic Viscosity, Yield Point, Gel Strength.

Purging The process of supplying an enclosure with a protective gas at a suffi-
cient flow and positive pressure to reduce the concentration of any flam-
mable gas or vapor initially present to an acceptable level.

Quebracho An additive used extensively for thinning/dispersing to control low-shear-
rate viscosity and thixotropy. It is a crystalline extract of the quebracho
tree consisting mainly of tannic acid. See: Thinner.

Quicklime Calcium oxide, CaO. Used in certain oil based drilling fluids to neutral-
ize the organic acid.

Quiescence The state of being quiet, at rest, or being still. See.- Static.

Radial Flow Flow of a fluid outwardly in a 360° pattern. This describes the flow from
a mechanical agitator in which fluid moves away from the axis of
the impeller shaft (usually horizontally toward a mud tank wall). See:
Axial Flow.

Radical Two or more atoms behaving as a single chemical unit (e.g., sulfate,
phosphate, and nitrate are radicals).

Rate of Penetration The rate at which the drill bit penetrates the formation expressed in lin-
eal units of feet/minute. See.- Penetration Rate, ROP.

Rate of Shear The change in velocity between two parallel layers divided by the dis-
tance between the layers. Shear rate has the units of reciprocal seconds
1
(sec- ). See.- Shear Rate.

Raw Drilling Fluid Drilling fluid, before dilution, that is to be processed by solids removal
equipment.

Rectangular Screen See: Oblong Mesh.

Reduced Port A valve whose bore size is less than the area of the pipe to which it
is attached.

Removal Section The first section in the drilling fluid system consisting of a series of
compartments and solids removal equipment to remove gas and unde-
sirable solids.

Reserve Pit (1) An earthen pit used to store drilling waste in land drilling operations.
(2) A section of a surface system used to store drilling fluid.

Residence Time Time a slurry or solids remain in a given location or region.

Resin A semi-solid, or solid complex, or amorphous mixture of organic com-
pounds having no definite melting point or tendency to crystalize. Resin
may be a component of compounded materials that can be added to
drilling fluids to impart special properties to the system (i.e., wall cake,
fluid loss, etc.).

Resistivity A characteristic electrical property of a material that is equal to the electri-
cal resistance of one meter cube of the material to passage of one ampere
electric current perpendicular to two parallel faces. The electrical resistance