|Energy Glossary Term
||A pool of petroleum locally confined by subsurface geologic features.
|API gravity (American Petroleum Institute gravity)
||A measure of how heavy or light a petroleum liquid is compared to water. If its gravity
is greater than 10, it is lighter and floats on water; if less than 10, it is heavier
and sinks. It is used to compare the relative densities of petroleum liquids.
||A formation, group of formations, or part of a formation that contains sufficient
saturated permeable material to yield significant quantities of water to wells and
|Barrels of Oil Equivalent (BoE)
||A unit of petroleum volume in which the gas part is expressed in terms of its energy
equivalent in barrels of oil.
|BTU (British Thermal Unit)
||The amount of heat needed to raise the temperature of one (1) pound of water by one
(1) degree Fahrenheit. The BTU is also used to measure the energy content of various
|Continuous Oil Accumulation
||A “continuous” or “unconventional” oil accumulation means that the oil resources is
dispersed throughout a geologic formation rather than existing as discrete, localized
occurrences, such as those in conventional accumulations. Unconventional resources
often require special technical drilling and recovery methods.
||A mixture of liquid hydrocarbons that exists in natural underground reservoirs as
distinguished from refined oils manufactured from it.
||The manner in which the water of an area passes or flows off by surface streams or
|Enhanced Oil Recovery
||Injection of steam, gas, or other chemical compounds into hydrocarbon reservoirs to
stimulate the production of usable oil beyond what is possible through natural pressure,
water injection, and pumping at the wellhead.
||An accumulation, pool, or group of pools of hydrocarbons or other mineral resources
in the subsurface. A hydrocarbon field consists of a reservoir with trapped hydrocarbons
covered by impermeable sealing rock, or trapped by hydrostatic pressure.
||Any remains, trace, or imprint of a plant or animal that has been preserved in the
Earth’s crust since some past geologic or prehistoric time. Fossils are found in sedimentary
||Any hydrocarbon that may be used for fuel: chiefly oil, natural gas, and coal.
||Also known as natural gas, is a naturally occurring hydrocarbon gas mixture consisting
primarily of methane with up to 20 percent of other hydrocarbons as well as impurities
in varying amounts.
||Gas hydrates are naturally occurring “ice-like” combinations of natural gas and water
that have the potential to provide an immense resource of natural gas from the world’s
oceans and polar regions. It is generally accepted that the volume of natural gas
contained in the world's gas hydrate accumulations greatly exceeds that of known gas
|Gas:Oil Ratio (GOR)
||Ratio of gas to oil (in cubic feet per barrel) in a hydrocarbon accumulation. GOR
is calculated by using volumes of gas and oil at surface conditions.
||A subsurface accumulation of hydrocarbons primarily in the gas phase that is contained
in porous or fractured rock formations. A gas accumulation is defined by the USGS
as having a gas:oil ratio of 20,000 cubic feet per barrel or greater.
||Any type of crude oil which does not flow easily. It is referred to as “heavy” because
its density or specific gravity is higher than that of light crude oil.
||A well development process that involves injecting water under high pressure into
a bedrock formation via the well. This is intended to increase the size and extent
of existing bedrock fractures.
||Any organic compound, gaseous, liquid, or solid, consisting solely of carbon and hydrogen.
||Liquid petroleum that has a low density and flows freely at room temperature.
||A colorless, odorless gas, the simplest paraffin hydrocarbon. It is the principal
constituent of natural gas and is also associated with crude oil.
||Hydrocarbons that exist as a gas or vapor at ordinary pressure and temperature.
|Natural Gas Liquids
||Those hydrocarbons in natural gas that are separated from the gas as liquids through
the process of absorption, condensation, or other methods in gas processing or cycling
||A naturally occurring complex liquid hydrocarbon, which after distillation and removal
of impurities yields a range of combustible fuels, petrochemicals, and lubricants.
||A subsurface accumulation of hydrocarbons composed primarily of oil that is contained
in porous or fractured rock formations.
||A combination of clay, sand, water, and bitumen, a heavy black viscous oil. Oil sands
can be mined and processed to extract the oil-rich bitumen, which is then refined
||A kerogen-bearing, finely laminated brown or black sedimentary rock that will yield
liquid or gaseous hydrocarbons on distillation.
||A measure of the ability of a rock to permit fluids to be transmitted through it;
it is controlled by pore size, pore throat geometry, and pore connectivity. Permeability
is typically reported in darcy units.
||A general term for all naturally-occurring hydrocarbons, whether gaseous, liquid,
||A term used to describe water that is produced along with oil and gas.
||A subsurface, porous, permeable rock body in which oil and/or gas have accumulated.
||Natural gas that can be generated and trapped within shale units.
||Liquid petroleum that can be generated and trapped within shale units.
||Rocks containing relatively large amounts of organic matter that is transformed into
||State jurisdiction begins at the established baseline for the coast and extends 3
geographic (nautical) miles.
||A large-scale structural formation of strata formed by tectonic down warping. Structural
basins may be sedimentary basins, which are aggregations of sediment that filled a
||Petroleum is considered “sweet” if it contains less than 0.5% sulfur compared to a
higher level of sulfur in sour crude oil.
||Natural gas trapped in a highly mixed mineralogy sandstone, shale, or limestone formations
which has very low permeability and porosity.
|Total Petroleum System (TPS)
||The essential elements (source, reservoir, seal, and overburden rocks) and processes
(generation-migration-accumulation and trap formation) as well as all genetically
petroleum that occurs in seeps, shows, and accumulations (discovered and undiscovered)
whose provenance is a pod or closely related pods of active source rock.
||A geologic feature that permits the accumulation and prevents the escape of accumulated
fluids (hydrocarbons) or injected carbon dioxide from the reservoir.