8. Non-conventional hydrocarbons

We are currently witnessing a major boom in the exploitation of unconventional hydrocarbons (including shale gas and shale oil) . Conventional hydrocarbons, whether oil or natural gas, are easy to recover from the reservoirs in which they are trapped and present in high concentrations. Unconventional hydrocarbons belong to the two families shown in figure 14 :

• those from very low-permeability reservoirs (less permeable than brick), known as...