A glossary of common terms and abbreviations used in the industry, with links to more in-depth articles on key words
N+2A - a measure of how well a heavy naphtha will perform when fed to a reformer, that is how high the octane of the resulting reformate will be
nC4 - (Normal butane) the lightest liquid stream produced in a refinery. The butane molecule has four carbon atoms and 10 hydrogen atoms
Name plate capacity - capacity of a process unit or plant based on original design
Nanhai light (crude) - a light, sweet crude grade produced in China
Naphtha - a broad term referring to distillation fractions and intermediates in the gasoline boiling range
Naphtha hydrotreater - (NHT) a refinery process unit that treats heavy naphtha streams, primarily to prepare them as feed to the reformer
Naphthene - hydrocarbons containing a saturated carbon ring (as opposed to aromatics which have an unsaturated carbon ring)
Napo (crude) - a heavy, sour crude grade produced in Ecuador
National oil company - (NOC) oil companies owned and operated by the government of the country they are in
Natural gas - (NG) a gas comprised primarily of methane, but typically with some ethane as well
Natural gas liquids - (NGL) liquids separated from natural gas as the gas is processed either in the field or at gathering points before moving to market
Natural gasoline - a type of light naphtha that comes from distillation cut comprised of pentane and slightly heavier naphtha-range material
NCI - (Nelson complexity index) a measure of the capital intensity of a refinery due the different process units that it contains
Needle coke - a specialty grade of pet coke valued for its crystalline structure that makes it a good material for making electrodes
Nelson complexity - (NCI) a measure of the capital intensity of a refinery due the different process units that it contains
Nemba (crude) - a light, sweet crude grade produced in Angola
Net-back price - a common price setting mechanism in which the price of a commodity is set in one place based on the value of the commodity in the market it is being sent to, minus the cost to move it to that market
New York Harbor - (NYH) a major refined product spot trading hub market
New York Mercantile Exchange - (NYMEX) a commodities exchange with very active trade in oil commodities and derivatives
NGL - (natural gas liquids) liquids separated from natural gas as the gas is processed either in the field or at gathering points before moving to market
Nickel - (Ni) a common metal found in trace amounts in crude oil
Nile blend (crude) - a light, sweet crude grade produced in Sudan
Nitrogen - (N2) an important contaminant in crude oil, typically in the form of organic nitrogen compounds
Niobrara Basin - a major crude oil production region in the interior of the US
Niobrara (crude) - a light, sweet crude grade produced in the US
No 1 oil - A fuel oil comprised of kerosene range material. Also called stove oil or range oil
No 2 oil - a diesel range light product used for non-transportation purposes
No 3 oil - a now obsolete light gasoil range fuel oil, that has been combined with No 2 oil
No 4 oil - A fuel oil comprised of VGO range material, intended for commercial heating furnaces lacking a preheater
No 5 oil - A fuel oil comprised of vac resid range material with a low viscosity, allowing it to be pumped without preheating. Also called Bunker B
No 6 oil - one of the lowest-value petroleum products from a refinery. It is essentially a byproduct of producing the light products that are the primary focus of a refinery
NOC - (National oil company) oil companies owned and operated by the government of the country they are in
Nomination - a request for capacity, typically on a pipeline or for ship loading/unloading facilities
Non-associated gas - natural gas that is produced from a gas well, rather than an oil well (associated gas)
NOR - (Notice of readiness) a notification given when a ship has entered port is ready to dock and begin loading or discharging a cargo
Normal butane - the lightest liquid stream produced in a refinery. The butane molecule has four carbon atoms and 10 hydrogen atoms
North Sea - a major crude oil production area and pricing point, offshore between the UK and Norway
Notice of readiness - (NOR) a notification given when a ship has entered port is ready to dock and begin loading or discharging a cargo
NW shelf (condensate) - a very-light, sweet crude grade from Australia
NWE - (Northwest Europe) a major refining center and oil spot market trading hub
Northwest Europe - (NWE) a major refining center and oil spot market trading hub
NOX - various nitrogen oxides created by the combustion of refined products and contributing to air pollution
NYMEX (exchange) - a commodities exchange with very active trade in oil commodities and derivatives
NYMEX crude (contract) - the exchange traded contract for domestic light, sweet crude (DSW) on the NYMEX commodities exchange