Oil and gas glossary
97 petroleum, reservoir, drilling, completions, production and geoscience terms, with short definitions written for working engineers.
15 of 97 terms match Petrophysics. Clear filters
B
-
Bulk density
RHOB
The density of the formation, grains and pore fluids together, from a density log.
C
-
Capillary pressure
Pc
The pressure difference between the non-wetting and the wetting fluid across their interface in the pores.
-
Connate water
Formation water that was already in the pores when the trap filled.
F
-
Fluid saturation
saturation
The fraction of the pore volume that one fluid occupies.
G
-
Gamma ray log
GR, gamma ray
A log of natural radioactivity along the borehole.
I
-
Irreducible water saturation
Swi, Swirr
The water saturation that further displacement by oil or gas will not reduce, at the capillary pressures that matter.
N
-
Net pay
pay
The thickness of reservoir that passes the cutoffs and is counted in the hydrocarbons in place.
-
Net to gross
NTG
Net thickness divided by the gross thickness of the same interval.
-
Neutron porosity
NPHI, neutron log
A porosity estimate from the hydrogen in the formation.
P
-
Permeability
perm, k
How readily a rock lets fluid pass through it for a given viscosity and pressure gradient.
-
Porosity
phi
The fraction of a rock's bulk volume that is pore space rather than solid grain.
R
-
Resistivity log
deep resistivity
A log of how strongly the formation resists electrical current.
S
-
Shale volume
Vsh
The fraction of the bulk rock treated as shale.
W
-
Water saturation
Sw
The fraction of pore volume filled with water.
-
Well log
log
A continuous record of a rock or fluid property against depth in a borehole.