BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
not that space is accessible to fluid penetration. Effective porosity refers to the amount of connected
pore spaces, i.e., the space available to fluid penetration. See Permeability.
Potassium - One of the alkali metal elements with a valence of 1 and an atomic weight of about 39.
Potassium compounds, most commonly potassium hydroxide (KOH) or potassium chloride (KCl)
are sometimes added to drilling fluids to impart special properties, usually inhibition.
Pound Equivalent - A laboratory unit used in pilot testing. One gram or pound equivalent, when
added to 350 mL of fluid, is equivalent to 1 lbm/bbl.
Parts Per Million (ppm) - Unit weight of solute per million unit weights of solution (solute plus
solvent), corresponding to weight- percent except that the basis is a million instead of a hundred. The
results of standard API titrations of chloride, hardness, etc. are correctly expressed in milligrams
(mg) per liter but not in ppm. At low concentrations mg/L is about numerically equal to ppm. A
correction for the solution specific gravity or density in g/mL must be made as follows:
ppm =
mg / L
solution Density,
gm / L
% by wt =
mg / L
( 10,000)( solution Density,
gm / L)
ppm
=
10,000
Thus, 316,000 mg/L salt is commonly and erroneously called 316,000 ppm or 31.6 percent, which
correctly should be 264,000 ppm and 26.4 percent, respectively.
Precipitate - Material that separates out of solution or slurry as a solid. Precipitation of solids in a
drilling fluid may follow flocculation or coagulation such as the dispersed red-bed clays upon
addition of a flocculation agent to the fluid.
Prehydration - The addition of a mud product to fresh water prior to adding it into the mud system.
Bentonite clay and XC polymers are two additives whose performance improves by hydration in
fresh water before adding them to a highly-treated or salty mud system.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-37