Definition : Chemical

Alkylation :

Refining process for converting light, gaseous olefins into high-octane gasoline components (reverse of cracking).

Aromatics :

Class of hydrocarbons that have at least one benzene ring as part of their structure. Generally describes benzene and benzene derivatives.

Associated Gas :

Natural gas associated with oil accumulations, either dissolved in oil or found as a cap of free gas above oil in reservoir.

Benzene :

An aromatic hydrocarbon present to a minor degree in most crude oils. (Products manufactured from benzene include styrene, phenol, nylon and synthetic detergents.)

Butane (C₄H₁₀) :

Either of two saturated hydrocarbons, or alkanes, with chemical formula. In both compounds carbon atoms are joined in an open chain.

Carbon :

Atomic number is 6; element is in group 14 (or IVa) of periodic table. Carbon content of a hydrocarbon determines, to a degree, hydrocarbon's burning characteristics and qualities.

Carbon Dioxide (CO₂) :

Colourless, odourless, and slightly acid-tasting gas, sometimes-called carbonic acid gas, molecule of which consists of one atom of carbon joined to two atoms of oxygen. Carbon dioxide in atmosphere tends to prevent escape of outgoing long-wave radiation from Earth to outer space; as more heat is produced and less escapes, temperature of Earth increases.

Carbon Monoxide (CO) :

Chemical compound of carbon and oxygen.

Chlorofluorocarbon (CFC) :

Synthetic chemical that is odourless, non-toxic, non-flammable, and chemically inert. Released into atmosphere, chlorine-containing chemicals rise and are broken down by sunlight, whereupon chlorine reacts with and destroys ozone molecules.

Coal :

During Carboniferous period much of world was covered with vegetation growing in swamps. This vegetation died and became submerged under water. As decomposition took place, vegetable matter lost oxygen and hydrogen atoms, leaving a peat deposit with a high percentage of carbon. As time passed, layers of sand and mud settled from water over some of peat deposits. Pressure of these overlying layers, as well as movements of earth's crust and sometimes volcanic heat, acted to compress and harden deposits, thus producing coal.

Condensate :

Liquid mixture of pentane and higher hydrocarbons.

Drilling Mud / Fluid :

Mixture of base substance and additives used to lubricate drill bit and to counter act natural pressure in formation. Drilling mud provides circulation, flushing rock cuttings from bottom of well bore to surface.

Drilling Mud Nomenclature :

Oil Based Mud (OBM), Pseudo Oil Based Mud (POBM), Water Based Mud (WBM).

Dry gas :

Or Lean gas is natural gas composed mainly of methane.

Esters :

Compounds formed by combination of acids and alcohols.

Ethanol :

Chemical formed by fermentation or synthesis.

Ethene :

Or Ethylene simplest member of class of aliphatic organic compounds called alkenes, which contain at least one carbon-carbon double bond. Ethylene is a colourless, slightly sweet-smelling gas of formula H₂C=CH₂. It is slightly soluble in water and is produced in commercial amounts by cracking and fractional distillation of petroleum and from natural gas.

Gasoline :

Mixture of lighter liquid hydrocarbons used chiefly as a fuel for internal-combustion engines. Produced by fractional distillation of petroleum; by condensation or adsorption from natural gas; by thermal or catalytic decomposition of petroleum or its fractions; by hydrogenation of producer gas or coal; or by polymerisation of hydrocarbons of lower molecular weight.

Greenhouse Gases :

Gases that alter thermal properties of atmosphere (for example, water vapour, carbon dioxide, methane, nitrous oxide, CFCs, halons and ozone).

Halons :

Halogenated carbon compounds used in fire extinguishing equipment and contributing to stratospheric ozone depletion. Being phased out under Montreal Protocol.

Heavy oil :

Long chains of hydrogen and carbon atoms.

Hexane :

Petroleum liquid found in small amounts in condensates.

Hydrocarbons :

Family of organic compounds, composed entirely of carbon and hydrogen (for example, coal, crude oil and natural gas).

Hydrogen (H) :

Reactive, colourless, odourless, and tasteless gaseous element with atomic number of 1. Element is usually classed in group 1 (or Ia) of periodic table. Lightest of all gases, hydrogen combines with carbon to form a variety of gaseous, liquid and solid hydrocarbons.

Hydrogenation :

Reacting coal with hydrogen at high pressures, usually in presence of a catalyst.

Light oil :

Shorter chains of hydrogen and carbon atoms.

Liquefied Natural Gas (LNG) :

Gas, mainly methane, liquefied under pressure and low temperature.

Liquefied Petroleum Gas (LPG) :

Pressure or refrigeration liquefies lighter hydrocarbons, such as propane, butane, pentane, and mixtures of these gases.

Material Safety Data Sheet (MSDS)

Issued by manufacturer of chemical substances that sets out hazards likely to be encountered by those who come into contact with substance.

Mercaptans :

Strong-smelling compounds of carbon, hydrogen and sulphur found in oil and gas. Added to natural gas for safety reasons.

Methane (CH₄) :

Also marsh gas, gas composed of carbon and hydrogen, first member of paraffin or alkane series of hydrocarbons. Methane contributed 12% (counting both direct and indirect global warming effects) of UK national greenhouse gas emissions in 1990. Oil and gas production accounted for 2% of national emissions in 1990.

Natural Gas :

Gas, occurring naturally, often found in association with oil.

Natural Gas Liquid (NGL) :

Liquid hydrocarbons found in association with natural gas.

Nitrous Oxide (N₂O) :

Nitrous Oxide contributed 5% of direct global warming potential from UK national greenhouse gas emissions in 1990.

Oil :

Mixture of liquid hydrocarbons of different molecular weights.

Olefins :

Basic chemicals made from oil or natural gas liquids feed stocks; commonly used to manufacture plastics and gasoline. Examples are ethylene and propylene.

Ozone :

Allotropic form of oxygen having three atoms in each molecule, formula O₃. Ozone formed in atmosphere from nitrogen oxides and organic gases emitted by automobiles and industrial sources.

Pentane :

One of lighter hydrocarbons, such as propane and butane, and mixtures of these gases are liquefied and employed as fuels.

Petrolatum :

Odourless, tasteless, greasy substance, obtained as residue from petroleum after lighter and more volatile components have been boiled off. Purified residue is obtained in form of a yellowish or decolourised semisolid, known as petroleum jelly in form of a clear to faintly yellow liquid, known as mineral oil.

Petroleum :

Generic name for hydrocarbons, including crude oil, NGLs, natural gas and their products.

Petroleum products :

Gasoline, kerosene, heavy fuel oil, lubricating oils, petroleum jelly, and paraffin consist principally of mixtures of paraffin hydrocarbons, which range from lighter liquid members to solid members.

Propane (C₃H₈) :

Colourless, odourless gas of alkane series of hydrocarbons. It occurs in crude oil, in natural gas, and as a by-product of petroleum refining.

Sour gas :

Natural gas containing significant quantities of hydrogen sulphide.

Sulphur Dioxide (SO₂) :

Acts as a precursor in formation of sulphate aerosols which, unlike greenhouse gases, have a net negative radiative forcing effect and tend to cool Earth's surface.

Synthetic Natural Gas (SNG) :

Gases made from coals and other hydrocarbon-containing substances.

Wet Gas :

Natural gas having significant amounts of heavier hydrocarbons in gasoline range.