Are hydrocarbon reservoirs that have low permeability and porosity and so are difficult to produce. Often enhanced recovery techniques, such as radial jetting, fracture stimulation or steam injection etc. must be performed, making the production process more difficult than a conventional play.
Worldwide Hydrocarbon Resources (BBOE)
Only a third of worldwide oil and gas reserves are considered conventional, the remainder being in unconventional resources.
Examples of unconventional resources are:
- Tight Gas
- Coalbed Methane (CBM)
- Shale Gas
- Shale Oil
- Heavy Oil/Tar sands
- Methane Hydrates