| Major |
| A term broadly applied to those multinational oil companies, which, by virtue of size, age, and/or degree of integration, are among the preeminent companies in the international petroleum industry. |
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| Marginal Cost Pricing |
| A method of setting prices in which price is made equal to marginal cost, that is, the cost of producing the next unit of output. |
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| Marker Crude |
| A crude selected as a standard in pricing, and often used as a reference in transactions such as futures sales. Some marker crudes include West Texas Intermediate, North Sea Brent, and in limited use within Canada, Swan Hills South. |
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| Market |
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| A context in which goods are bought and sold, not necessarily confined to a particular geographic location. |
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| Marketable Natural Gas |
| Natural gas which is available to a transmission line after removal of certain hydrocarbons and non-hydrocarbon compounds present in the raw gas, and which meets specifications for use as a domestic, commercial or industrial fuel. Marketable natural gas excludes field and plant fuel and losses, excepting those related to downstream reprocessing plants. Also referred to as pipeline gas. |
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| Mast |
| Portable derrick that can be erected as a unit, instead of assembled part by part. |
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| Megawatt (MW) |
| One megawatt is the unit of power equal to 1,000 kilowatts. MW(th) denotes the thermal power of a generating station, that is, the rate at which heat is produced (by combustion if it is a conventional thermal plant, by fission in the reactor core if it is a nuclear reactor). MW(e) denotes the electrical power output of the station and is only a fraction of the thermal power - typically about 30% for a heavy water reactor and up to 40% for a modern fossil-fuel-fired station. The latter radio - MW(e)/MW(th) - is called the thermal efficiency of the power station. |
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| Mercaptans |
| Sulfur compounds resembling alcohols, but with the oxygen of the hydroxyl group replaced by sulfur. Often found in petroleum products, mercaptans have a particularly strong and disagreeable odour. |
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| Methanation |
| The final step in high-Btu gas production, in which hydrogen-rich gas reacts with carbon monoxide in the presence of a catalyst, to form methane. |
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| Methane |
| A colourless, odourless, hydrocarbon gas (CH4) Used as a fuel. Methane is the principal constituent of natural gas. |
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| Methanol |
| A one-carbon alcohol made from natural gas, coal or biomass. Aldo called methyl alcohol or wood alcohol. |
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| Middle Distillates |
| A term broadly applied to hydrocarbons in the so-called "middle range" of refinery distillation. Examples are light heating oil, diesel fuel, gas-oil and kerosene. |
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| Miscible Flooding |
| An enhanced oil recovery process in which fluid, capable of dissolving in the oil it contacts, is injected into a reservoir to form a single liquid that can move through the reservoir to a producing well more easily than the original crude oil. |
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| Moderator |
| A material used in a nuclear reactor core to slow down fast neutrons, without unduly absorbing them, in order to increase the probability that the neutrons will cause fission in a uranium-235 or plutonium-239 nucleus. |
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| Mogas |
| Industry slang for motor gasoline. |
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| Motor Octane Number (MON) |
| The earlier of two numerical systems for measuring gasoline octane. The octane number of a gasoline reflects its anti-knock properties, that is, its ability to withstand compression without detonating in an internal combustion engine. |
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| Mud |
| A mixture of base substance and additives used to lubricate
the drill bit and to counteract the natural pressure of the formation. |