Page 487 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 463

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Glossary

available; an Atmospheric balance and a Pressurized balance. In the
pressurized balance, the top screws down and more mud can be
injected by a hand pump through a non-return valve in the lid. A
pressurized balance will give a more accurate figure for downhole
mud density if any aeration is present.

Barite or Baryte. Natural barium sulphate used for increasing the
density of drilling fluids. If required, it is usually upgraded to a spe-
cific gravity of 4.20.

Barrel. A volumetric unit of measure used in the petroleum industry
consisting of 42 US gallons or 38 Imperial gallons.

Basicity. pH value above 7. Ability to neutralize or accept protons
from acids.

Bell Nipple. A short piece of pipe, expanded or belled at the top, to
guide tools into the hole. Usually has side connections for the fill-up
and mud return lines.

Bentonite. A plastic, colloidal clay, largely made up of the mineral
sodium montmorillonite, a hydrated aluminum silicate. For use in
drilling fluids, bentonite has a yield in excess of 85 lb/ton. The
generic term “bentonite” is neither an exact mineralogical name, nor
is the clay of definite mineralogical composition.

Bicarb. Sodium Bicarbonate. Used for treating cement contamina-
tion in drilling fluid.

Bit Breaker. A heavy plate which fits in the rotary table and holds
the bit while it is being unscrewed from the drill collar.

Block line. Wire rope used to raise and lower the block by means of
the drawworks.

Blowout. An uncontrolled escape of drilling fluid, gas, oil or water
from the well, caused by the formation pressure being greater than
the hydrostatic head of the fluid in the hole.

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