Inch – (col), unit of length, equal to 24. 5 mm.
Inorganic theory – a theory of the origin of hydrocarbons (petroleum and natural gas) through chemical reactions in the lithosphere, without the influence of live matter (organic matter).
Injection well – a well intended for injecting water and natural gas into a reservoir during secondary methods, injecting natural gas into underground storage, etc.
Isomers – compounds of identical molecular formulas, but with different arrangement of structural groups (for example, n-pentane and iso-pentane)
Isomerisation – modification of structural formula of n-paraffin into iso-paraffins.