Page 351 - Geology and Geochemistry of Oil and Gas

312 APPENDIX C

Expectation [stat] The average value resulting from an infinite series
of repetition of an experiment or observations of a
random variable. Symbol: E.
Extraclasts Particles derived from outside the basin of carbonate
deposition. Cf: Intraclasts.

F
Fabric The orientation, or lack of orientation, of the
elements (particles, crystals, cement) in a sedimentary
rock.
Facies Sum of all lithologic, biologic, and diagenetic
attributes in a rock from which the origin and
environment of deposition can be inferred. The term
can be restricted to lithologic facies (lithofacies),
depositional facies, biotic facies (biofacies), or
diagenetic facies.
Fan See: Alluvial fan.
Fault A break in subsurface strata.
Fault trap The sealing of a porous and permeable reservoir
formation by the abutment of an impermeable bed
juxtaposed by fault action.
Fenestrae General term for penecontemporaneously formed
shrinkage pores or gas-bubble pores in rocks, both
larger than interparticle pore spaces; includes ‘‘bird
eyes’’ and larger pores such as sheetcracks. Also in
reference to pore types in carbonate rocks. Adj:
Fenestral.
Field An area consisting of a single reservoir or multiple
reservoirs all grouped on or related to, the same
individual structural feature and/or stratigraphic
condition.
Filter cake The layer of concentrated solids from the drilling mud
or cement slurry that forms on the walls of the
borehole opposite the porous and permeable
formation. See also: Mud cake.
Filtrate The liquid portion of drilling mud that is forced into
porous and permeable formations next to the
borehole.
Flare Burning off excess natural gas at a well or other
production site.
Floating offshore drilling A type of mobile offshore drilling unit that floats and
rig is not secured to the seafloor (except for anchors).
Floating units include inland barge rigs, drill ships