2. Non-conventional hydrocarbons

2.1 Petroleum system concept

From a strictly geological point of view, conventional and unconventional hydrocarbons result from a single process: the transformation of organic matter contained in certain geological layers – the bedrock – over geological time by increasing temperature and pressure as it is buried (figure 6 ). To obtain liquid hydrocarbons (oil), the temperature of the bedrock must reach 70 to 80°C, corresponding to a burial depth of around 2 to 2.5 km. For gaseous hydrocarbons, this temperature must reach 100 to 110°C. Depending on the nature of the bedrock (lake, sea or land), different hydrocarbons are generated.