Page 505 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 481

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Glossary

tional relationship, a constant for the material can be calculated. The
constant is Youngs Modulus of Elasticity (E).

Hopper, Jet. A device to hold or feed drilling mud additives.

Horsepower (hp). Is a rate of doing work (transferring energy)
equivalent to lifting 33,000 pounds at 1 foot per minute (33,000
ftlb/min). This is of course also 550 ftlb/sec.

Hostile Environment Litho Density Tool. Schlumberger wireline tool
that measures the density of the formation and also gives short and
long spaced photoelectric effect measurements. Can deduce lithology
and porosity. A caliper is also given.

Hydration. The act of a substance to take up water by means of
absorption and/or adsorption.

Hydraulics. That branch of engineering which treats of liquids in
motion, or its action. It is the know-how about the effects of fluid
velocities and pressures and the power involved. The pressure of either
a standing or a moving column of fluid is directly related to its density
(weight per unit volume), but the moving column is also concerned
with a pressure relation due to friction of flow or change of velocity as
well as density. This friction is related to viscosity (resistance to flow)
mainly for smooth (laminar) flow, but it is more concerned with densi-
ty for turbulent flow which involves most practical situations.

Hydrogen Ion Concentration. A measure of the acidity or alkalinity
of a solution, normally expressed as pH. See also pH.

Hydrometer. A floating instrument for determining the specific grav-
ity or density of liquids, solutions, and slurries. A common example
is the “Mudwate” hydrometer used to determine the density of mud.

Hydrostatic Head. The pressure exerted by a column of fluid, usual-
ly expressed in pounds per square inch. To determine the hydrostatic
head at a given depth in psi, multiply the depth in feet by the density
in pounds per gallon by 0.052.

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