BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Gumbo - A generic term for soft, sticky, swelling clay formations that are frequently encountered in
surface holes offshore or in sedimentary basins onshore near seas. This clay fouls drilling tools and
plugs piping, both sever problems for drilling operations. It is a nonspecific type of shale that
becomes sticky when wet and adheres aggressively to surfaces. It forms mud rings and balls that can
plug the annulus, the flowline and shale-shaker screens. Gumbo is likely to contain appreciable
amounts of Ca ++ smectite clays. It is dispersed in a water mud, causing rapid accumulations of
colloidal solids.
Guar Gum - A naturally occurring hydrophilic polysaccharide derived from the seed of the guar
plant. The gum is chemically classified as a galactomannan. Guar gum slurries made up in clear,
fresh, or brine water possesses pseudo-plastic flow properties.
Gunk Plug or Squeeze - A slurry in crude or diesel oil containing any of the following materials or
combinations - bentonite, cement, attapulgite, and guar gum (never with cement), used primarily in
combating lost circulation. The plug may or may not be squeezed.
Gunning the Pit - The mechanical agitation of the drilling fluid in a pit by means of, a high pressure
fluid gun, electric mixer, or agitator.
Gyp or Gypsum - See Calcium Sulfate. Gypsum is often encountered while drilling. It may occur
as thin stringers or massive formations.
Hardness (of Water) - The hardness of water is due principally to the calcium and magnesium ions
present in the water and is independent of the accompanying acid ions. The total hardness is
measured in terms of parts per million of calcium carbonate or calcium and sometimes equivalents
per million of calcium. For hardness tests, see API RP 13B.
Heaving - The partial, intermittent, or complete collapse of the walls of a hole resulting from internal
pressures due primarily to swelling from hydration or formation gas pressures. See Sloughing.
Heterogeneous - A substance that consists of more than one phase and is not uniform, such as
colloids, emulsions, etc. It has different properties in different parts.
High-pH fluid - A drilling fluid with a pH range above 10.5, a high-alkalinity fluid.
High-Yield Drilling Clay - A classification given to a group of commercial drilling-clay
preparations having a yield of 35 to 50 bbl/ton and intermediate between bentonite and low-yield
clays. High- yield drilling clays are usually prepared by peptizing low-yield calcium montmorillonite
clays or, in a few cases, by blending some bentonite with the peptized low-yield clay.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-22