Chemical compound – matters consisting of identical molecules made of atoms of several elements; matter consisting of more elements.
Cogeneration – simultaneous production of electrical power using gas and steam turbines.
Collector – perforated (porous) and permeable rock (deposit, layer) where fluids and gases can accumulate; when vaulted by impermeable rocks, can be a reservoir of petroleum and natural gas.
Compressor station – (CS), facility for compressing natural gas to a higher pressure, consists of necessary number of compressors with engines running on gas or electricity.
Concession – (approval), document granting the right to explore and exploit raw materials owned by the state.
Condensation – transformation of vapours into liquid state by cooling.
Condensate – mixture of light hydrocarbons in a liquid state.
Conversion – interrelation of light products (gases, petrol and gas oils) and residue, in relation to entry raw material, expressed in percentages. Conversion depends on the type of raw material, pressure, temperature and spatial velocity. Conversion also means transforming one product into another.
Cracking – chemical reaction of cracking big organic molecules and making small molecules under the effect of higher temperature. By cracking molecules of kerogen, bitumen and petroleum are produced, and by cracking oil, condensate and gas are produced.
Calorific value/Heat capacity – quantity of heat produced by combustion of a certain quantity of energy sources (fuel); expressed in units of heat (energy, operation) J (joule) accompanied by a unit of quantity of fuel, for example: J/kg or MJ/kg for fuel oils.
Catalysts – chemical compounds that expedite chemical reactions but do not participate in these reactions.
Central gas station (CGS) – facilities and plants where natural gas is collected from several gas stations, purified from harmful admixtures and delivered for further treatment, for underground storage or into the gas transportation system.
Col - inch; designation: «in» or «"»; unit of length; 1 col = 25, 4 mm