Page 491 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 467

[ ]
Glossary

Choke Line. Extension from the blowout presenter stack used to
direct and control well fluids from the annulus when the BOPs are
closed.

Choke Manifold. A series of chokes and valves used to restrict and
direct the flow of fluid and/or gas.

Christmas Tree. A term applied to the valves and fittings assembled
at the top of a well to control the flow of oil or gas.

Chrome Lignite. Mined lignite, usually leonardite, to which chromate
has been added and/or reacted. The lignite can also be causticized
with either sodium or potassium hydroxide.

Chronological Sample Taker. Schlumberger wireline tool that can
recover up to 90 core samples per trip. An explosive charge fires a
hollow bullet into the formation, which is attached to the tool with
wires. When the tool is moved, the bullet and sample are pulled out
of the formation.

Circulation. The movement of drilling fluid from the suction pit
through pump, drill pipe, bit, annular space in the hole and back
again to the suction pit. The time involved is usually referred to as
circulation time.

Circulation Rate. The volume flow rate of the circulating drilling
fluid usually expressed in gallons or barrels per minute.

Circulation, Loss Of or Lost Circulation. The result of drilling fluid
escaping into the formation by way of crevices or porous media.

Clay. A plastic, soft, variously colored earth, commonly a hydrous sil-
icate of alumina, formed by the decomposition of feldspar and other
aluminum silicates. Clay minerals are essentially insoluble in water
but disperse under hydration, shearing forces such as grinding, veloc-
ity effects, etc., into the extremely small particles varying from submi-
cron to 100-micron sizes.

467