BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Sodium Bicarbonate - NaHCO 3 . A material used extensively for treating cement contamination and
occasionally other calcium contamination in drilling-fluids. It is the half -neutralized sodium salt of
carbonic acid.
Sodium Bichromate - Na 2 Cr 2 O 7 . Also correctly called "sodium dichromate." See Chromate.
Sodium Carbonate - Na 2 CO 3 - A material used extensively for treating out various types of calcium
contamination- It is commonly called "soda ash." When sodium carbonate is added to a fluid, it
increases the pH of the fluid by hydrolysis. Sodium carbonate can be added to salt (NaCl) water to
increase the density of the fluid phase.
Sodium Carboxymethylcellulose - Commonly called CMC. Available in various viscosity grades
and purity. An organic material used to control filtration, suspend weighting material, and build
viscosity in drilling fluids. Used in conjunction with bentonite where low-solid fluids are desired.
Sodium Chloride - NaCl. Commonly known as salt. Salt may be present in the fluid as a
contaminant or may be added for any of several reasons. See Salt.
Sodium Chromate - Na 2 CrO 4 . See Chromate.
Sodium Hydroxide - NaOH. Commonly referred to as "caustic" or "caustic soda." A chemical used
primarily to impart a higher pH.
Sodium Polyacrylate - A synthetic high molecular weight polymer of acrylonitrile used primarily as
a fluid loss control agent.
Sodium Silicate Fluids - Special class of inhibited chemical fluids using as their bases sodium
silicate, salt, water, and clay.
Solids Concentration or Content - The total amount of solids in a drilling fluid as determined by
distillation includes both the dissolved and the suspended or undissolved solids. The suspended
solids content may be a combination of high and low-specific gravity solids and native or
commercial solids. Examples of dissolved solids are the soluble salts of sodium, calcium, and
magnesium. Suspended solids make up the wall cake; dissolved solids remain in the filtrate. The total
suspended and dissolved solids contents are commonly expressed as percent by volume, and less
commonly as percent by weight.
Solubility - The degree to which a substance will dissolve in a particular solvent.
Solute - A substance which is dissolved in another (the solvent).
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-43