Page 522 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 498

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Glossary

run to guide a joint while it is being screwed into the joint in the
rotary table.

Standpipe. Part of the circulating system. A pipe extending, usually
along a derrick leg, to a height suitable for attaching the rotary hose.

Strain. When a material has a force applied to it, the material
deforms. Strain is a measure of the expansion divided by the original
length L. See also Hooke’s Law.

Stratigraphic High Resolution Dipmeter Tool. Schlumberger wireline
tool that determines structural and stratigraphic dip, stratigraphic
analysis, fracture identification, and borehole geometry.

Stress. When a material has a force applied to it, that force can be
expressed as the force exerted over the cross sectional area. For met-
als it is usually expressed in pounds per square inch (psi). See also
Hooke’s Law.

Supersaturation. If a solution contains a higher concentration of a
solute in a solvent that would normally correspond to its solubility at
a given temperature, this constitutes supersaturation. This is an
unstable condition, as the excess solute separates when the solution
is seeded by introducing a crystal of the solute. The term “supersatu-
ration” is frequently used erroneously for hot salt muds.

Surfactant. A material which tends to concentrate at an interface.
Used in drilling fluids to control the degree of emulsification, aggrega-
tion, dispersion, interfacial tension, foaming, defoaming, wetting, etc.

Surge Loss. The flux of fluids and solids which occurs in the initial
stages of any filtration before pore openings are bridged and a filter
cake is formed. Also called “spurt loss.”

Swabbing. When pipe is withdrawn from the hole in a viscous mud
or if the bit is balled, a suction is created.

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