Oil and gas glossary
97 petroleum, reservoir, drilling, completions, production and geoscience terms, with short definitions written for working engineers.
12 of 97 terms match Geoscience. Clear filters
A
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Aquifer
Water-bearing rock in pressure communication with the hydrocarbon column.
F
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Fault
A fracture across which the rock on one side has moved relative to the other.
G
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Gamma ray log
GR, gamma ray
A log of natural radioactivity along the borehole.
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Gas-oil contact
GOC
The depth where a gas cap sits on the oil column.
N
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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.
R
-
Reservoir
A body of subsurface rock porous and permeable enough to store hydrocarbons and to give them up to a well.
S
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Seal
cap rock, top seal
A layer whose pores will not let the hydrocarbon column beneath it pass.
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Source rock
A rock rich enough in organic matter, and buried hot enough for long enough, to have generated oil or gas.
T
-
Trap
A configuration of rock that stops migrating hydrocarbons and lets them accumulate.
W
-
Water-oil contact
WOC, OWC
The depth where the oil column gives way to water.
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Well log
log
A continuous record of a rock or fluid property against depth in a borehole.