1.
n. [Formation Evaluation]
A particular relation between the
formation factor (F) and
porosity (
phi) proposed by the Humble Oil Company. The original formula was expressed as F = 0.62 /
phi^{2.15}. A nearly equivalent form, with a simpler porosity exponent, is F = 0.81 /
phi^{2}. These formulae are considered most suitable for relatively high-porosity, sucrosic, or granular, rocks.
See Winsauer WO, Shearin HM, Masson
PH and Williams M:
Resistivity of
Brine-Saturated Sands in Relation to
Pore Geometry,
AAPG Bulletin 36 (1952): 253-277.