Page 492 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 468

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Glossary

Coagulation. In drilling-fluid terminology, a synonym for
Flocculation.

Cohesion. The attractive force between the same kind of molecules,
i.e., the force which holds the molecules of a substance together.

Colloid. A substance that is in a state of division preventing passage
through a semi-permeable membrane and in suspension or solution
fails to settle out and diffracts a beam of light.

Compensated Density Neutron Tool. Schlumberger/Anadrill LWD
tool which combines density and neutron porosity in one tool.
Useful for gas detection, porosity evaluation, and lithology determi-
nation.

Compensated Dual Resistivity Tool. Schlumberger/Anadrill LWD
tool that measures resistivity at two depths of investigation. Also
measures spectral gamma ray to give relative proportions of potassi-
um, thorium, and uranium.

Compensated Neutron Log. Schlumberger wireline tool that bom-
bards the formation with fast neutrons. Detectors measure the
slowed neutrons that are bounced back by Hydrogen atoms. Used to
deduce porosity, lithology, clay analysis, and gas detection.

Conductivity. A measure of the quantity of electricity transferred
across unit area per unit time. It is the reciprocal of resistivity.
Electrolytes may be added to the drilling fluid to alter its conductivity
for logging purposes.

Connate Water. Water that probably was laid down and entrapped
with sedimentary deposits, as distinguished from migratory waters
that have flowed into deposits after they were laid down.

Consistency. The viscosity of a non-reversible fluid, in poises, for a
certain time interval at a given pressure and temperature.

Contamination. The presence in a drilling fluid of any foreign

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