Soils or rock which contain an appreciable amount of calcium carbonate usually from limestone.

A unit used to measure the energy content in food. This unit of energy is defined as the amount of energy needed to raise the temperature of 1 gram of water by 1°C.

Calorific (heating) value
The quantity of heat that can be liberated from one pound of coal or oil measured in BTU’s.

A metal shaft supporting the cams that cause the open/close operation of the intake and exhaust valves. The camshaft turns at 1/2 the speed of the crankshaft and is connected to it either via gears, a timing chain or a timing belt.

An element forming a large number of compounds, many of which have important uses. Diamond and graphite are amongst the main forms of carbon. Coals are elemental carbon mixed with varying amounts of carbon compounds; coke and charcoal are nearly pure carbon. All organic compounds, such as proteins, carbohydrates, and fats, contain carbon, and all plant and animal cells consist of carbon compounds and their polymers.

Carbon cycle
Is the exchange of carbon between land, atmosphere and oceans. About one quarter of the total carbon (in the form of carbon dioxide) in the atmosphere is cycled in and out each year; half of this is exchanged with the land biota (see), and the other half, through physical and chemical processes, across the ocean’s surface.

Carbon dioxide
A colorless, odorless gas that is produced when animals (including humans) breathe or when carbon-containing materials (including fossil fuels) are burned. Carbon dioxide is essential to the photosynthesis process that sustains plant and animal life, however, it can accummulate in the air and trap heat near the Earth’s surface (the “greenhouse effect”).

Carbon monoxide
A colorless, odorless, highly poisonous gas made up of carbon and oxygen molecules formed by the incomplete combustion of carbon or carbonaceous material, including gasoline. It is a major air pollutant on the basis of weight.

Carbon tax
A financial tax imposed on the sales of fossil fuels. In this form of fuel tax, the level of taxation is determined by the carbon content of each fuel. Users of natural gas would pay less than users of petroleum gasoline.

A compound containing carbon and oxygen; examples are calcium carbonate (limestone)and dolomite which are common carbonate sedimentary rocks. Carbonate sedimentary rocks fizz when diluted acid are applied to them.

A carcinogen is any agent, chemical, physical or biological, that can act on living tissue in such a way as to cause a malignant neoplasm. More simply, a carcinogen is any substance which causes cancer.

Development of carcinoma; or, in more recent usage, producing any kind of malignancy.

Malignant new growth made up of epithelial cells tending to infiltrate the surrounding tissues and give rise to metastases.

Pipe cemented in the well to seal off formation fluids or keep the hole from caving in.

Alteration of the speed of a chemical reaction, through the presence of an additional substance, known as a catalyst (see), that remains chemically unchanged by the reaction. Enzymes, which are among the most powerful catalysts, play an essential role in living organisms, where they accelerate reactions that otherwise would require temperatures that would destroy most of the organic matter.

A substance which aids or promotes a chemical reaction without forming part of the final product. It enables the reaction to take place faster, remains unchanged at the end of the reaction and can provide control by increasing desirable reactions and decreasing undesirable reactions.

Catalytic converter
An air pollution abatement device that removes organic contaminants by oxidising them into carbon dioxide and water.

Catalytic reforming
The classic refinery process used to obtain high octane gasoline and in which gasoline from the primary distillation of crude, or naphtha, is used as feedstock.

Cathodic protection
A method of preventing oxidation of the exposed metal in structures by imposing between the structure and the ground a small electrical voltage.

The main carbohydrate in living plants. Cellulose forms the skeletal structure of plant cell wall.

Injection of cement into the annulus (space) between the casing (see) and the well wall to consolidate the latter and reduced water influxes.

Centrifugal force
An apparent force that appears only in rotating frames of reference.

(see Cetane Number)

Cetane Number (C.N.)
A measure of ignition quality of diesel fuel. The higher the cetane number the easier the fuel ignites when injected into an engine, resulting in lower emissions.

(see Chlorofluorocarbons)

Chemical bond
The main carbohydrate in living plants. Cellulose forms the skeletal structure of plant cell wall.

Chemical energy
Energy contained in the molecular structure of a substance; a form of potential energy which is converted to other forms of energy through some type of chemical reaction.

Chemical Oxygen Demand (COD)
A measure of the oxygen required to oxidize all compounds in water, both organic and inorganic.

Chemical properties
A property observed when a substance undergoes a transformation into one or more new substances.

Chemical reaction
The science that systematically studies the composition, properties, and activity of substances and various elementary forms of matter.

The science that systematically studies the composition, properties, and activity of substances and various elementary forms of matter.

Heavy, greenish-yellow, irritating gas with a pungent odor. Capable of reacting with almost all other elements. Catalyst for ozone destruction.

The amount of chlorine in water by weight (with all bromides and oxides converted to chloride).

Any of a number of substances consisting of chlorine, fluorine, and carbon. CFCs are used for refrigeration, foam packaging, solvents, and propellants. They have been found to cause depletion of the atmosphere’s ozone layer.

The science of geographical regions, plant and animal distribution.

Christmas tree
The assemblage of valves and fittings at the top of a well used in the control of production.

A process in which suspended material is removed from a wastewater (see). This may be accomplished by sedimentation, with or without chemicals, or filtration.

A very fine grained material, smaller than silt (clay has a diameter of less than 1/256 mm). Clay is formed by the weathering and breaking down of rocks and minerals.

Clean ballast
(see Ballast)

Refers to the temperature, humidity, precipitation, winds, radiation, and other meteorological conditions characteristic of a locality or region over an extended period of time. Compared to weather; climate involves longer times and deals not only with the atmosphere, but also with oceans, land and biosphere.

Climate change
Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity. This usage differs from that in the United Nations Framework Convention on Climate Change (UNFCCC), which defines ‘climate change’ as: ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. (source: European Environment Agency)

Climax community
The final or most stable animal or plant community in a succession series; the final outcome of a slow, orderly progression of changes in communities in an area over time. A climax community is capable of maintaining itself indefinitely as long as the environment is not disturbed by, say, the introduction of some other species or some extreme geological or climate event.

The process of creating a living organism or embryo that has the same genetic composition as an already existing or previously existing individual. Most discussion about human cloning refers to the procedure known as “somatic cell nuclear transfer.” Other cloning methods include parthenogenesis and twinning.

CNG (Compressed Natural Gas)
Natural gas that has been compressed under high pressure, typically between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when released for use as a fuel.

A readily combustible black or brownish-black rock whose composition, including inherent moisture, consists of more than 50 percent by weight and more than 70 percent by volume of carbonaceous material. It is formed from plant remains that have been compacted, hardened, chemically altered, and metamorphosed by heat and pressure over geologic time. Coal classifications The categories below are based on fixed carbon, volatile matter, coking properties and heating value. Lignite – Low-rank, brown coals which are distinctly brown and woody or claylike in appearance, and which contain relatively high moisture contents of between 30 and 70 percent of the fuel by weight. Sulfur may range from low to high and heating value may range from 3,500 to 7,000 Btu/lb.Subbituminous – Young black coal with high moisture content of between 15 and 40 percent by weight. In the U.S. the most often cited example is the Power River Basin coal found in Wyoming and Montana. Heating value varies from 7,000 Btu/lb to slightly over 9,000 Btu/lb. This type of coal is considered by many to have the largest reserves by weight around the world. Countries such as Indonesia and Malaysia have much more subbituminous coal that bituminous coal. Sulfur value is typically quire low, and ash is also usually low. Volatile matter is usually high, and can exceed 40% of the weight of the cal “as received.”Bituminous – Older geologic age than subbituminous coal, with higher heating value, and higher in volatile matter and ash than subbituminous coal. Used for both steam and electricity production, as well as for production of steel. Metallurgical coal is typically bituminous coal, with a free swelling index of over 4.5 and with “dial divisions per minute ” (a measure of “fluidity”) of over 1,500 and sometimes over 20,000. Heating value of bituminous coal typically ranges from 10,000 to 13,000 Btu/lb.Anthracite – A form of coal often referred to as “hard coal,” which is generally used in the production of steel, characterized by low volatile matter, low sulfur, low ash, low Hargrove index (indicating a hard coal) and high heating value. Sometimes blended with bituminous coal in sized coal cargoes to increase heating value. Heating value is often at or above 13,500 Btu/lb.

Coal oil
Oil that can be obtained by distilling bituminous coal.

Coal rank
The classification of coals according to their degree of progressive alteration from lignite to anthracite. In the United States, the standard ranks of coal include lignite, subbituminous coal, bituminous coal, and anthracite and are based on fixed carbon, volatile matter, heating value, and agglomerating (or caking) properties.

Coal washing
The process of removing impurities, such as ash and sulfur based compounds, from coal.

The simultaneous generation of electricity and thermal energy for industrial, commercial, heating, or cooling purposes. This energy system consumes a fuel, usually natural gas, to produce electricity and thermal energy in the form of steam or hot air. Cogeneration systems use heat energy that otherwise would be wasted.

1. Coke (Coal) A solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal from which the volatile constituents are driven off by baking in an oven at temperatures as high as 2,000 degrees Fahrenheit so that the fixed carbon and residual ash are fused together. Coke is used as a fuel and as a reducing agent in smelting iron or in a blast furnace. Coke from coal is grey, hard, and porous and has a heating value of 24.8 million Btu per ton. 2. Coke (Petroleum) A residue high in carbon content and low in hydrogen that is the final product of thermal decomposition in the condensation process in cracking. This product is reported as marketable coke or catalyst coke. The conversion is 5 barrels (of 42 U.S. gallons each) per short ton. Coke from petroleum has a heating value of 6.024 million Btu per barrel.

A cracking plant for heavy petroleum fractions used for the high yield production of high value added products and the production of coke.

Colonial species
Referring to animals that live together in colonies.

Establishment of a community of microorganisms at a specific site or ecosystem.

The reaction of organic substances with the oxygen present in the atmosphere. It produces carbon oxides, water vapour and thermal energy.

A symbiotic relationship in which one member is benefited and the second is neither harmed nor benefited.

(see Biocenosys)

Organisms using resources and reducing the availability of those resources to other organisms.

The installation of permanent wellhead equipment for the production of oil and gas.

Organic residues, or a mixture of organic residues and soil, that have been mixed, piled, and moistened (with or without the addition of fertilizer and lime) and generally allowed to undergo aerobic thermophillic decomposition until the original organic matter has been substantially altered or decomposed.

The biological degradation of organic material under aerobic (oxygen-rich) conditions to produce compost, a nutrient-rich soil amendment and conditioner.

Compressed Natural Gas (CNG)
Natural gas in high-pressure surface containers that is highly compressed (though not to the point of liquefaction). CNG is used extensively as a trans-portation fuel for automobiles, trucks and buses in some parts of Italy, New Zealand, and in Western Canada, and has recently begun to penetrate some regions of the United States. Small amounts of natural gas are also transported overland in high-pressure containers.

Compressor station
A permanent facility that houses compressor units used to maintain natural gas pipeline pressure.

This is the organisation set up by petroleum companies operating in Europe. It is concerned with the problems of the environment, health and safety and the technico-economic implications of the refining, distribution and marketing of petroleum products.

Concession contracts
Contracts currently applied mainly in Western countries regulating relationships between States and oil companies with regards to hydrocarbon exploration and production. The company holding the mining concession has an exclusive on mining activities and for this reason it acquires a right on hydrocarbons extracted, against the payment of royalties to the State on production and taxes on oil revenues.

The change in state of matter from vapor to liquid that occurs with cooling. Usually used in meteorology when discussing the formation of liquid water from vapor. This process releases latent heat energy to the environment.

Conditioning of radioactive waste
Operation that transforms radioactive waste into a safe condition for transport, storage and/or disposal. (source: United Nations Statistics Division).

A material that carries a force such as metal carries heat or electricity.

Introduction into water, air and soil of microorganisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects, buildings and various household and agricultural use products.

Market situation where prices are higher for forward delivery dates than for nearer delivery dates. See also backwardation.

Controlled landfill
Controlled landfill is landfill whose operation is subject to a permit system and to technical control procedures in compliance with the national legislation in force. Includes specially engineered landfill.

Conventional density
The gravity of crude oil. Density is measured in kilograms of large, carbon-rich molecules per cubic metre or degrees on the American Petroleum Institute (API) gravity scale.

The thermal or catalytic processing of petroleum fractions in order to produce better quality products with a minor impact on the environment when employed by the end-user. It takes place in complex high-temperature and high-pressure plant.

Conversion factors
A number that translates units of one system into corresponding values of another system. Conversion factors can be used to translate physical units of measure for various fuels into BTU equivalents.

Coral bleaching
Corals are built by tiny animals called polyps, which are nourished by algae called zooxanthellae. Coral bleaching occurs when water temperature or other conditions become inhospitable to the zooxanthellae and they die, followed swiftly by the polyps. The coral is left white and barren.

Coral reef
Complex tropical marine ecosystem dominated by soft and hard (stony) corals, anemones and sea fans. Stony corals are microscopic animals with an outer skeleton of calcium carbonate that form colonies and are responsible for reef building.

Samples of subsurface rocks taken as a well is being drilled. The core allows geologists to examine the strata in proper sequence and thickness.

Core analysis
Analysis of rock samples which are cut downhole and brought to the surface for examination to determine characteristics such as porosity and permeability.

CORINAIR (COoRdination INformation – AIR)
CORINAIR is a project performed since 1995 by the European Topic Centre on Air Emissions under contract to the European Environment Agency. The aim is to collect, maintain, manage and publish information on emissions into the air, by means of a European air emission inventory and database system. This concerns air emissions from all sources relevant to the environmental problems of climate change, acidification, eutrophication, tropospheric ozone, air quality and dispersion of hazardous substances.

Coring bit
A specialized drilling bit for cutting and removing rock samples from the bottom of a well.

Coriolis effect
Tendency for any moving body on or above the Earth’s surface to drift sideways from its course because of the earth’s rotational direction (west to east) and speed, which is greater for a surface point near the equator than toward the poles. In the Northern Hemisphere the drift is to the right of the motion; in the Southern Hemisphere, to the left. In most human-operated vehicles, continuous course adjustments mask the Coriolis effect. The Coriolis effect must be considered, however, when plotting ocean currents and wind patterns as well as trajectories of free-moving projectiles through air or water.

The dissolution and wearing away of metal caused by a chemical reaction such as between water and pipes, chemicals touching a metal surface, or contact between two metals.

Part of seed surrounding the embryo, the cotyledon serves as a source of nutrients for the germinating plant. The number of cotyledons in the seed serves as a basis for classifying angiosperms into monocotyledons, with one cotyledon, and dicotyledons, with two.

Crack spread
The simultaneous purchase or sale of crude against the sale or purchase of refined petroleum products. These spread differentials which represent refining margins are normally quoted in dollars per barrel by converting the product prices into dollars per barrel and subtracting the crude price.

Refinery process whereby large, heavy, complex hydrocarbon molecules are broken down into simpler and lighter molecules in order to derive a variety of fuel products.

A narrow crack or opening.

Crude (petroleum)
(see Petroleum)

Any of a large class (Crustacea) of mostly aquatic mandibulate arthropods that have a chitinous or calcareous and chitinous exoskeleton, a pair of often modified appendages on each segment, and two pairs of antennae; includes lobsters, shrimps, crabs, wood lice, water fleas, and barnacles.

A crystal is a homogeneous, solid body of a chemical element, compound or isomorphous mixture. In a crystal the atoms are repeated in a regular arrangement and this arrangement may be outwardly expressed by the plane faces of the crystal.

Cubic meter
A measurement composed of the amount of natural gas that would fill an imaginary box measuring 1’x1’x1’. For comaparison:1 cubic meter = 1 m3 = 35.30101 cubic feet (ft3) 1 cubic foot = 1 ft3 = 0.0283278 m3 103m33: = One Thousand Cubic Meters (1000 m3) of gas. (A box measuring 1m x 1m x 1m is a cubic meter. Fill it with natural gas).

Fragments of rock dislodged by the bit and brought to the surface in the drilling mud.

A type of separator for removal of larger particles from an exhaust gas stream. Gas laden with particulates enters the cyclone and is directed to flow in a spiral causing the entrained particulates to fall out and collect at the bottom. The gas exits near the top of the cyclone.




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