Page 301 - Shale Shakers Drilling Fluid Systems

GLOSSARY 283

Axial Flow Flow from a mechanical agitator in which the fluid first moves along the
axis of the impeller shaft (usually down toward the bottom of a tank) and
then away from the impeller. See: Radial Flow.

Back Pressure The frictional or blocking pressure opposing fluid flow in a conduit. See.-
Differential Pressure.

Back Tank The compartment on a shale shaker that receives drilling fluid from the
flow line. See.- Possum Belly, Mud Box.

Backing Plate The plate attached to the back of screen cloth(s) for support.

Backup Screen See: Support Screen.

Baffles Plates or obstructions built into a compartment to change the direction
of fluid flow.

Balanced Design A hydrocyclone that has the lower apex adjusted to the diameter of the
Hydrocyclone cylinder of air formed within the cone by the cyclonic forces of drilling
fluid spinning within the cone. This tends to minimize liquid discharge
when there are no separable solids.

Balanced Elliptical Motion An elliptical motion of a shale shaker screen such that all ellipse axes
are tilted at the same angle toward the discharge end of the shale shaker.

Ball Valve A valve that uses a spherical closure with a hole through its center, which
rotates 90° to open and close.

Barite Natural barium sulfate, BaSO 4, is used for increasing the density of drill-
ing fluids. The API standard requires a minimum of 4.20 specific gravity.
Commercial barium sulfate ore can be produced from a single ore or a
blend or ores, and may be a straight-mined product or processed by flo-
tation methods. It may contain accessory minerals other than the barium
sulfate mineral. Because of mineral impurities, commercial barite may
vary in color from off-white or gray to red or brown. Common accessory
minerals are silicates such as quartz and chert, carbonate compounds
such as siderite and dolomite, and metallic oxide and sulfide compounds.

Barite Recovery Efficiency Barite recovery efficiency is the ratio of the mass flowrate of barite re-
turning to a drilling fluid from a solids control device, divided by the mass
flowrate of barite in the feed to the solids control device.

Barium Sulfate BaSO 4. See.- Barite.

Barrel A volumetric unit of measure used in the petroleum industry consisting
of 42 U.S. gallons.

Barrel Equivalent One gram of material in 350 ml of fluid is equivalent to a concentration
of 1 Ib of that material in an oil field barrel of fluid. See.- Barrel, Pound
Equivalent.

Base A compound of a metal, or a metal-like group, with hydrogen and oxy-
gen in proportions that form an OH~ radical when ionized in an aqueous
solution, yielding excess hydroxyl ions. Bases are formed when metallic
oxides react with water. Bases increase the pH. Examples of bases are
caustic soda (NaOH) and lime (Ca(OH) 2).