Page 509 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 485

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Glossary

Lignosulfonates. Organic drilling fluid additives derived from by-
products of sulphite paper manufacturing process from coniferous
woods. Some of the common salts, such as the ferrochrome, chrome,
calcium, and sodium, are used as universal dispersants while others
are used selectively for calcium treated systems. In large quantities,
the ferrochrome and chrome salts are used for fluid-loss control and
shale inhibition.

Lime. Commercial form of calcium hydroxide.

Lime-Treated Muds. Commonly referred to as “lime-base” muds.
These high-pH systems contain most of the conventional freshwater
additives to which sacked lime has been added to impart spacial
properties. The alkalinities and lime contents vary from low to high.

Liner. Any string of casing whose top is situated at any point below
the surface inside of another casing.

Litho Density Log. Schlumberger wireline tool that measures bulk
density and photoelectric effect of the formation using a pad mount-
ed gamma ray source and two detectors. Can deduce porosity, litholo-
gy, and abnormal pressures.

Live Oil. Crude oil that contains gas and has not been stabilized or
weathered. This oil can cause gas cutting when added to mud and is a
potential fire hazard.

Logging while drilling. Tools that are run as part of the drilling
assembly which measure downhole parameters. Data can be transmit-
ted real time to surface and/or may be recorded downhole for trans-
mission to a workstation once the tool is back on surface.

Lost Circulation Additives or Lost Circulation Material or LCM.
Materials added to the mud to control or prevent lost circulation.
These materials are added in varying amounts and are classified as
fiber, flake, or granular.

Lost Returns or Lost Circulation. To encounter an interruption in

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