BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
centimeter. Since the surface tension of a liquid is approximately equal to the interfacial tension
between the liquid and air, it is common practice to refer to values measured against air as surface
tension, and to use the term "interfacial tension" for measurements at an interface between two
liquids, or a liquid and a solid.
Surge Loss - The flux of fluids and solids which occurs in the initial stages of any filtration before
pore openings are bridged and a filter cake is formed. Also called "spurt loss."
Suspensoid - A mixture consisting of finely divided colloidal particles floating in a liquid. The
particles are so small that they do not settle but are kept in motion by the moving molecules of the
liquid (Brownian movement).
Swabbing - When pipe is withdrawn from the hole in a viscous fluid or if the bit is balled, a suction
is created. This process can cause a reduction in hydrostatic head resulting in the intrusion of
formation fluids, or in some cases, collapse of the formation into the well bore.
Swelling - See Hydration.
Synergism, Synergistic Properties - Term describing an effect obtained when two or more products
are used simultaneously to obtain a certain result. Rather than the results of each product being
additive to the other, the result is a multiple of the effects.
Tannic Acid - Tannic. acid is the active ingredient of quebracho and other quebracho substitutes
such as mangrove bark, chestnut extract, etc.
Temperature Survey - An operation to determine temperatures at various depths in the hole. This
survey is used to find the location of inflows of water into the hole, where doubt exists as to proper
cementing of the casing and for other reasons.
Ten-Minute Gel - See Gel Strength, Ten-Minute.
Thermal Decomposition - The chemical breakdown of a compound or substance by temperature
into simple substances or into its constituent elements. Starch thermally decomposes in drilling fluids
as the temperature approaches 300°F.
Thinner - Any of various organic agents (tannins, lignins, lignosulfonates, etc.) and inorganic agents
(pyrophosphates, tetraphosphates, etc.) that are added to a drilling fluid to reduce the viscosity and/or
thixotropic properties.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-46