Page 526 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 502

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Glossary

for directional drilling.

Wildcat. A well in unproved territory.

Workover Fluid. Any type of fluid used in the workover operation of
a well.

Workover. To perform one or more of a variety of remedial opera-
tions on a producing oil well with the hope of restoring or increasing
production. Examples of workover operations are deepening, plug-
ging back, pulling and resetting the liner, squeeze cementing, shoot-
ing, and acidizing.

Yield Point. In drilling fluid terminology, yield point means yield
value. Of the two terms, yield point is by far the most commonly
used expression.

Yield. A term used to define the quality of a clay by describing the
number of barrels of a given centipoise slurry that can be made from
a ton of the clay. Based on the yield, clays are classified as bentonite,
high-yield, low-yield, etc. Not related to yield value below.

Youngs Modulus of Elasticity (E). Youngs Modulus is calculated for
metals by dividing stress by strain. See also Hooke’s Law. Youngs
Modulus for steel (Imperial units) is approximately 30 x 106.

Zero-Zero Gel. A condition wherein the drilling fluid fails to form
measurable gels during a quiescent time interval (usually 10 min).

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