Page 303 - Shale Shakers Drilling Fluid Systems

GLOSSARY 285

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 forma-
tions and/or cuttings or material that prevents a tubular string from mov-
ing down a borehole.

Brine Water containing a high concentration of common salts such as sodium
chloride, calcium chloride, calcium bromide, zinc bromide, and so forth.
Bromine Value The number of centigrams of bromine that are absorbed by 1 gram of
oil under certain conditions. The Bromine Check is is a test for the de-
gree 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 which, when dissolved in
water, produces a solution that resists a change in its hydrogen ion con-
centration upon the addition of acid or base.

Cable Tool Drilling A method of drilling a well by allowing a weighted bit (or chisel) at the
bottom of a cable to fall against the formation being penetrated. The
cuttings are then bailed from the bottom of the wellbore using a bailer.
See/ Rotary Drilling.

Cake Consistency According to API Bulletin RP 13B, terms such as "hard," "soft," "tough,"
"rubbery," "firm," and the like, may be used to convey some idea of
cake consistency.
Cake Thickness (1) A measurement of the filter cake thickness deposited by a drilling fluid
against a porous medium, usually filter paper, according to the standard
API filtration test. Cake thickness is usually reported in 32nds of an inch
or millimeters. (2) The filter cake thickness deposited on the wall of a
borehole. See.- Filter Cake, Wall Cake.

Calcium One of the alkaline earth elements with a valence of 2 and an atomic
weight of about 40. Calcium compounds are a common cause of water
hardness. Calcium is also a component of lime, gypsum, limestone, and
so forth.

Calcium Carbonate (1) CaCO 3. An acid soluble calcium salt sometimes used as a weighting
material (limestone, oyster shell, etc.) in specialized drilling fluids. (2) A term
used to denote a unit and/or standard to report hardness. See: Limestone.

Calcium Chloride CaCl 2. A very soluble calcium salt sometimes added to drilling fluids to
impart special inhibitive properties, but primarily used to increase the
density of the liquid phase (water) in completion fluids and as an inhibi-
tor to the water phase of invert oil emulsion drilling fluids.

Calcium Contamination Dissolved calcium ions in sufficient concentration to impart undesirable
properties in a drilling fluid such as flocculation, reduction in bentonite