Page 359 - Geology and Geochemistry of Oil and Gas

320 APPENDIX C

Level of significance The probability of committing an error while rejecting
the null hypothesis when it is really true or a threshold
value of probability at or below which the results of
statistical investigation (e.g., hypothesis testing) are
held to contradict a particular hypothesis. This
probability is expressed as decimal or percentage;
level of significance supplements the level of
confidence to 1 or 100% (often this probability is set
at 0.05 or 5%).
Lift mechanisms Various methods of lifting oil from the wellbore to the
surface. It includes: artificial lift, cable lift, electric
submersible lift, gas lift, hydraulic lift, rod lift, and
surface lift.
Lighter ends Volatile components (or fractions) of petroleum.
Lignin The substance that gives tensile strength to plant
structures such as tree trunks. It is a polymer of
propylbenzene nuclei joint by oxygen and carbon
linkages plus –OH and –OCH 3 side chains.
Lignite A brownish-black coal that is intermediate in
coalification between peat and sub-bituminous coal.
Cf: Brown coal.
Lime mud A general term for carbonate sediment composed of
particles up to 62 microns in size.
Lipids A broad term that includes all oil- and water-soluble
substances such as fats, waxes, fatty acids, steroids,
pigments, and terpenoids.
Lithification Process of converting unconsolidated sediments to
rocks by the addition of mineral cement. Syn:
Consolidation. Partial syn: Cementation.
Lithoclast Mechanically or biogenically formed and deposited
fragment (larger than 2 mm) of a weakly lithified
sediment or rock, formed within the basin of
deposition. Cf: Extraclast.
Lithofacies See: Facies.
Lithographic texture Compact, dense, homogenous and exceedingly
fine-grained rock with conchoidal or
subconchoidal fracture. Partial syn: Micrite,
Carbonate mudstone.
Lithology Descriptive, physical characteristics of rocks such
as color, structure, mineralogic composition, grain
size, etc.
Live oil Oil that contains gas.
Log Continuous record of certain data obtained from a
logging tool lowered into the wellbore.