Page 337 - Geology and Geochemistry of Oil and Gas

298 APPENDIX C

Authigenic Formed or generated in place; specifically said of
minerals that have precipitated in place or which have
replaced other minerals or particles in various
diagenetic environments.
Autochthonous Said of sediments or rocks that have accumulated in
place. Cf: Allochthonous, Allogenous. Syn:
Authigenous.
B
Backstepping Referring to carbonate platforms that are being
eroded or tectonically drowned such that their areal
dimensions are progressively reduced in a landward
direction.
Bafflestone Reef rock that has accumulated as a result of the
trapping or baffling of sediments amidst in-place
organic framework.
Ball sealers Rubber balls dropped into a wellbore to plug
perforations.
Bank Limestone deposits consisting of skeletal matter
formed by in-place organisms or sediments deposited
generally in shallow water; in both cases the deposit
may be surrounded by deeper water.
Barefoot Well completed without casing.
Barite A mineral often used as a component of drilling mud
(or fluid) to add weight: barium sulfate (BaSO 4 ),
SGE4.3. Syn: Heavy spar.
Barrel A unit of petroleum liquid measure equal to 42
gallons, US.
Barrier reef Long, linear reef oriented parallel to shoreline and
separated from it at some distance by a lagoon of
considerable depth and width; generally occur along
the margins of shallow-water platforms, and pass
seaward into deeper-water environments.
Basin (a) A depressed area with no surface outlet.
(b) A low area in the Earth’s crust, of tectonic origin,
in which sediments have been accumulated.
Benzene An aromatic hydrocarbon (C 6 H 6 ) found in
petroleum. Used as solvent for petroleum products.
Used as synonym for gasoline in many European
countries.
Bindstone Reef rock that has accumulated as a result of
the presence of tabular or lamellar fossils
that encrusted or otherwise bound sediments
during deposition. Partial syn: Boundstone,
Biolithite.