Backpressure. The frictional or blocking pressure opposing fluid flow ina conduit. See: differential pressure.
Back tank. The compartment on a shale shaker that receives drillingfluid from the flowline. 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 thedirection of fluid flow.
Balanced design hydrocyclone. A hydrocyclone that has the lower apex adjusted to the diameter of the cylinder of air formed within the cone by the cyclonic forces of drilling fluid spinning within 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 and rotates 90 to open and close.
Barite. Natural barium sulfate, BaSO4, is used for increasing the density of drilling 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 of ores and may be a straight-mined product or processed by flotation methods. It may contain minerals other than barium sulfate. Because of mineral impurities, commercial barite may vary in color from off-white to 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 flow rate of barite returning to a drilling fluid from a solids control device divided by the mass flow rate of barite in the feed to the solids-control device.
Barium sulfate. BaSO4. See: barite.
Barrel (bbl). 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 lb of that material in an oilfield barrel of fluid.See: barrel, pound equivalent.
Base. A compound of a metal, or a metal-like group, with hydrogen and oxygen in the 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.
Base exchange. The replacement of the cations associated with the surface of a clay particle by another species of cation, for example,the substitution of sodium cations by calcium cations on the surface of a clay particle. See: methylene blue titration, methylene blue test, MBT, cation exchange capacity, CEC.
Basicity. pH value above 7. Ability to neutralize or accept protons from acids. See: pH.
Basket. That portion of a shale shaker containing the deck upon which the screen(s) is mounted; supported by vibration isolation members connected to the bed.
Beach. Area between the liquid pool and the solids discharge ports in a decanting centrifuge or hydrocyclone.
Bed. Shale shaker support member, consisting of mounting skid or frame with or without bottom, flow diverters to direct screen underflow to either side of the skid, and mountings for vibration isolation members.
Bentonite. A colloidal clay, largely made up of the mineral sodium montmorillonite, a hydrated aluminum silicate. Used for developing a low shear rate viscosity and/or good filtration characteristics in water-based drilling fluids. The generic term ‘‘bentonite’’ is not an exact mineralogical name, nor is the clay of definite mineralogical
composition. See: gel, montmorillonite.
Bentonite (clay) extender. Additive that interacts with clay in a drilling fluid to boost viscosity; usually this at a low to moderate concentration of polymer and depends on the polymer/clay ratio.
Bernoulli Principle. One means of expressing Newton’s Second Law of Physics, that is, concerning conservation of energy. Roughly stated,this principle demonstrates that the sum of pressure and velocity through or over a device represents equal quantities, neglecting the effects of losses due to friction and/or increases by adding energy with external devices such as pumps.
Bicarb. See: sodium bicarbonate.
Bingham model. A mathematical description that relates shear stress to shear rate in a linear manner. This model requires only two constants (plastic viscosity and yield point) and is the simplest rheological model possible to describe a non-Newtonian liquid. It is very useful for analyzing drilling fluid problems and treatment. See: viscosity, pseudoplastic fluid, plastic viscosity, yield point, gel strength.
Blade. See: flight, flute.
Blinding: A reduction of open area in a screening surface caused by coating or plugging. See: coating, plugging.
Blooie line. The flowline for air or gas drilling.
Blowout. An uncontrolled escape of drilling fluid, gas, oil, or water from the well caused by the formation pressure being greater than the hydrostatic head of the fluid being circulated in the well bore. See: kick, kill fluid.
Bonded screens. Multiple screens bonded together with plastic to form a multilayered screen or screens bonded to a metal support plate.
Bonding material. Material used to secure screen cloth to a backing plate or support screen.
Bottom flooding. The behavior of a hydrocyclone when the underflow discharges whole drilling fluid rather than separated solids.
Bound liquid. Adsorbed liquid. See: absorb, absorption, adsorb, adsorption, adsorbed liquid.
Bow. See: crown.
Bowl. The outer rotating chamber of a decanting centrifuge.
Brackish water. Water containing low concentrations of any soluble salts.
Break circulation. To start movement of the drilling fluid after it has been quiescent in a borehole.
Bridge. An obstruction in a well formed by the intrusion of subsurface formations and/or cuttings or material, which prevents a tubular string from moving down a borehole.
Brine. Water containing a high concentration of common salts such as sodium chloride, calcium chloride, calcium bromide, zinc bromide, etc.
Bromine value. The number of centigrams of bromine that are absorbed by 1 gram of oil under certain conditions. The bromine check is a test for the degree of unsaturation of a given oil.
Brownian movement. Continuous, irregular motion exhibited by particles suspended in a liquid or gaseous medium, usually as a colloidal dispersion.
BS&W. Base sediment and water.
Buffer. Any substance or combination of substances that, when dissolved in water, produces a solution that resists a change in its hydrogen ion concentration upon the addition of an acid or base.