Non-conventional oil is oil produced or extracted using techniques other than the traditional oil well method. Currently, non-conventional oil production is less efficient and some types have a larger environmental impact relative to conventional oil production.
Non-conventional types of production include: Tar Sands, Extra Heavy Oil, Oil Shale, Bitumens, biofuels, thermal depolymerization (TDP) of organic matter, as well as conversion of Coal To Liquid , Coal Gasification or Natural Gas to Liquid.
These non-conventional sources of oil may be increasingly relied upon as petrol motor fuel for transportation as conventional oil becomes "economically non-viable" due to depletion. Growing political risk, is also stoking interest in alternative resources.
Conventional sources of oil are currently preferred because they provide a much higher ratio of extracted energy over energy used in extraction and refining processes. Technology, such as using steam injection in tar sands deposits, is being developed to increase the efficiency of non-conventional oil production.
Historically, conventional natural gas deposits have been the most practical, and easiest, deposits to mine. However, as technology and geological knowledge advances, unconventional natural gas deposits are beginning to make up an increasingly larger percent of the supply picture.
So what exactly is unconventional gas? A precise answer to that question is hard to find. What was unconventional yesterday, may through some technological advance, or ingenious new process, become conventional tomorrow. In the broadest sense, unconventional natural gas is gas that is more difficult, and less economically sound, to extract, usually because the technology to reach it has not been developed fully, or is too expensive.
What is really considered unconventional natural gas changes over time, and from deposit to deposit. The economics of extraction play a role in determining whether or not a particular deposit may be unconventional, or simply to costly to extract.
A potential new source of unconventional gas is through the underground gasification of coal.
- Information from naturalgas.org