BAKER HUGHES - Drilling Fluids Reference Manual

GLOSSARY OF TERMS
Percent - For weight -percent, see ppm. Volume-percent is the number of volumetric parts of any
liquid or solid constituent per 100 like volumetric parts of the whole. Volume-percent is the most
common method of reporting solids, oil, and water contents of drilling fluids.
Permeability - Normal permeability is a measure of the ability of rock to transmit a one-phase fluid
under conditions of laminar flow. Unit of permeability is the Darcy.
P f - The phenolphthalein alkalinity of the filtrate, reported as the number of milliliters of 0.02 Normal
(N/50) acid required per milliliter of filtrate to reach the phenolphthalein end point.
pH - An abbreviation for potential hydrogen ion. The pH numbers range from 0 to 14, 7 being
neutral, and are indices of the acidity (below 7) , or alkalinity (above 7) of the fluid. The numbers are
a function of the hydrogen ion concentration in gram ionic weights per liter which, in turn, is a
function of the dissociation of water as given by the following expression:
( H )( OH )
H
2
O
=
K H O
2
= 1×
10
−υ
The pH may be expressed as the logarithm (base 10) of the reciprocal (or the negative logarithm) of
the hydrogen ion concentration. The pH of a solution offers valuable information as to the immediate
acidity or alkalinity, as contrasted to the total acidity or alkalinity (which may be titrated).
Phosphate - Certain complex phosphates, usually sodium tetraphosphate (Na 6 P 4 O 13 ) and sodium
acid pyrophosphate (SAPP, Na 2 H 2 P 2 O 7 ), are used either as fluid thinners or for treatment of various
forms of calcium-and magnesium contamination
Pilot Testing - A method of predicting behavior of fluid systems by mixing quantities of fluid or
fluid additives, then testing the results.
Plastic Flow - See Plastic Fluid.
Plastic Fluid - A complex, non-Newtonian fluid in which the shear force is not proportional to the
shear rate. A definite pressure is required to start and maintain movement of the fluid. Plug flow is
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 15-35