Glossaire :Cap rock [...] Cutter

Cap rock (see the French definition ): The cap rock is a barrier, an impermeable rock which stops oil and gas from traveling up towards the surface.
Casing tubes (see the French definition ): The internal wall of a well is unstable and the sides of the well can collapse. To prevent this from happening, large hollow steel cylinders are regularly placed along the length of the hole during drilling (like pipes, they can be lowered into the well in sections that are then screwed together). These are called “casing tubes”. Once the casing has been installed, drilling can resume, although the diameter of the hole will be smaller. This is because the casing that has just been installed takes up space and reduces the initial diameter of the hole. Thus a drilling hole that started with a 50cm diameter may be reduced to a 20cm diameter after a number of casing tubes have been inserted.
Catalytic cracking (see the French definition ): Catalytic cracking is a process that is performed at high temperatures to transform heavy molecules into lighter hydrocarbons. Three-quarters of the heavy molecules are transformed into gas, gasoline and diesel. All heavy molecules can be transformed into lighter hydrocarbons for a price.
Cellulosic ethanol (see the French definition ): Cellulosic ethanol is a type of biofuel (or renewable fuel) produced from plant waste (e.g. from straw or wood waste). It is just as efficient as “standard” ethanol, but is more environmentally friendly to manufacture (reuse of otherwise unusable waste).
CFC/HCFC (see the French definition ): CFCs (chlorofluorocarbons) are compounds made of carbon, chlorine and fluorine and HCFCs (hydrochlorofluorocarbons) contain carbon, chlorine, fluorine and hydrogen. They are gases at room temperature and pressure and were used not so long ago as coolants in air conditioning units and as propellants in aerosol cans. They are gases which destroy the ozone layer in the stratosphere and thereby contribute to the greenhouse effect. It is forbidden to manufacture them and it is now illegal to use them.
Chain reaction (see the French definition ): In order to trigger a nuclear fission reaction, the nucleus of a uranium-235 atom is bombarded by neutrons. The nucleus breaks up and releases heat and radiation. It also frees other neutrons which can then bombard other atoms, which are in turn subjected to the fission reaction. This is what is known as a chain reaction.
Chemical stimulation (see the French definition ): When engineers want to increase the oil or gas extraction flow from reservoirs with poor permeability, they can use chemical stimulation techniques. Hydrochloric acid is injected to dissolve carbonates or hydrofluoric acid is injected to dissolve silica (acidification). This technique greatly enhances permeability.
Chernobyl (see the French definition ): A city in Ukraine where a nuclear reactor exploded in 1986 causing major and irrevocable damage to the human population and the environment.
CO2 (see the French definition ): Carbon dioxide. This is the main greenhouse gas (GHG) because of the amount of CO2 that is emitted into the atmosphere.
Cogeneration (see the French definition ): Cogeneration is the simultaneous production of both heat (thermal energy) and electricity (produced when mechanical energy is produced) in the same facility.
Coke (see the French definition ): Coke is a material derived from coal that is made of almost pure carbon in which any volatile compounds have been removed.
Coker (see the French definition ): Cokers are arrays of dozens of 8m-high furnaces used for the fast production of large quantities of coke from coal.
Coking (see the French definition ): Coking is a thermal process which involves turning a coal mix into coke by heating it to a very high temperature (1000°C). The process is also used to obtain various by-products (e.g. gas, tar, gasoline, methane).
Concentrated solar power plant (see the French definition ): Concentrated solar power plants channel the sun’s rays using reflectors and then convert them into electricity. There are three types: parabolic trough systems (parallel alignments of long semi-cylindrical reflectors); solar power towers (swivelling mirror panels that transfer the captured heat to a boiler at the top of a tower); and parabolic dish systems (parallel rows of long, curved mirrors that track the course of the sun).
Concession contract (see the French definition ): The use of this type of contract has been gradually reduced since the 1960s but it is very popular with oil companies. The producing State receives royalties of fixed sums that are calculated according to the amount of oil that is produced, irrespective of the oil selling price. Moreover, the oil companies use the oil as they see fit: they can set the production levels as they wish.
Consortium (see the French definition ): A consortium is a group of individuals or institutions which could be private or public (e.g. businesses, universities, researchers, etc.). Consortia enable large-scale projects to be undertaken by pooling financial and material resources. For example, Total has an 8.33% interest in the consortium responsible for building the EPR™ nuclear power plant in Penly, Greater Paris (with French energy companies EDF and GDF Suez).
Cooling system (see the French definition ): A reactor in a nuclear power station has 3 circuits. The third circuit is the cooling system which cools the steam generator with cold water (water taken from the sea or river and the cooling towers).
Core (see the French definition ): The term used for the part of the nuclear reactor which is filled with water and which is where fission takes place.
Core drilling (see the French definition ): Core drilling or sampling is used during the drilling phase of a deposit (e.g. an oil deposit). It involves taking a cylindrical sample from the ground. From its composition it is possible to learn about the accessibility, quality and viability of the deposit, as well as its extraction conditions.
Core sample (see the French definition ): Cylindrical section of rock that is taken to find out about the characteristics of the subsoil.
Corrosion (see the French definition ): Corrosion is the gradual disintegration of a material, a surface or a substance by either a chemical or physico-chemical reaction.
Crude (oil) (see the French definition ): Oil that has not been refined.
Cutter (see the French definition ): A mechanical ore extraction machine used to extract coal from mines.