Unconventional oil

Unconventional oil is petroleum produced or extracted using techniques other than the conventional (oil well) method. Oil industries and governments across the globe are investing in unconventional oil sources due to the increasing scarcity of conventional oil reserves. Unconventional oil and gas have already made a dent in international energy linkages by reducing US energy import dependency.Conventional oil is a category that includes crude oil - and natural gas and its condensates. Crude oil production in 2011 stood at approximately 70 million barrels per day. Unconventional oil consists of a wider variety of liquid sources including oil sands, extra heavy oil, gas to liquids and other liquids. In general conventional oil is easier and cheaper to produce than unconventional oil. However, the categories “conventional” and “unconventional” do not remain fixed, and over time, as economic and technological conditions evolve, resources hitherto considered unconventional can migrate into the conventional category. Unconventional oil is petroleum produced or extracted using techniques other than the conventional (oil well) method. Oil industries and governments across the globe are investing in unconventional oil sources due to the increasing scarcity of conventional oil reserves. Unconventional oil and gas have already made a dent in international energy linkages by reducing US energy import dependency. According to the International Energy Agency's (IEA) World Energy Outlook 2001 unconventional oil included 'oil shales, oil sands-based synthetic crudes and derivative products, (heavy oil, Orimulsion®), coal-based liquid supplies, biomass-based liquid supplies, gas to liquid (GTL) - liquids arising from chemical processing of gas.' In the IEA's World Energy Outlook 2011 report, 'nconventional oil include extra-heavy oil, natural bitumen (oil sands), kerogen oil, liquids and gases arising from chemical processing of natural gas (GTL), coal-to-liquids (CTL) and additives.' In their 2013 webpage jointly published with the Organisation for Economic Co-operation and Development (OECD), the IEA observed that as technologies and economies change, definitions for unconventional and conventional oils also change. According to the US Department of Energy (DOE), 'unconventional oils have yet to be strictly defined.' In a communication to the UK entitled Oil Sands Crude in the series The Global Range of Crude Oils, it was argued that commonly used definitions of unconventional oil based on production techniques are imprecise and time-dependent. They noted that the International Energy Agency does not recognize any universally accepted definition for 'conventional' or 'unconventional' oil. Extraction techniques that are categorized as 'conventional' use 'unconventional means' such as gas re-injection or the use of heat' not traditional oil extraction methods. As the use of newer technologies increase, 'unconventional' oil recovery has become the norm not the exception. They noted that the Canadian oil sands production 'pre-dates oil production from areas such as the North Sea (the source of a benchmark crude oil known as 'Brent'). Under revised definitions, petroleum products, such as Western Canadian Select, a heavy crude benchmark blend produced in Hardisty, Alberta may migrate from its categorization as unconventional oil to conventional oil because of its density, even though the oil sands are an unconventional resource. Oil sands generally consist of extra heavy crude oil or crude bitumen trapped in unconsolidated sandstone. These hydrocarbons are forms of crude oil that are extremely dense and viscous, with a consistency ranging from that of molasses for some extra-heavy oil to as solid as peanut butter for some bitumen at room temperature, making extraction difficult. These heavy crude oils have a density (specific gravity) approaching or even exceeding that of water. As a result of their high viscosity, they cannot be produced by conventional methods, transported without heating or dilution with lighter hydrocarbons, or refined by older oil refineries without major modifications. Such heavy crude oils often contain high concentrations of sulfur and heavy metals, particularly nickel and vanadium, which interfere with refining processes, although lighter crude oils can also suffer from sulfur and heavy metal contamination. These properties present significant environmental challenges to the growth of heavy oil production and use. Canada's Athabasca oil sands and Venezuela's Orinoco heavy oil belt are the best known example of this kind of unconventional reserve. In 2003 the estimated reserves were 1.2 trillion barrels (1.9×1011 m3). Heavy oil sands and bituminous sands occur worldwide. The two most important deposits are the Athabasca Oil Sands in Alberta, Canada and the Orinoco heavy oil belt in Venezuela. The hydrocarbon content of these deposits is either crude bitumen or extra-heavy crude oil, the former of which is often upgraded to synthetic crude (syncrude) and the latter of which the Venezuelan fuel Orimulsion is based. The Venezuelan extra heavy oil deposits differ from the Canadian bituminous sands in that they flow more readily at Venezuela's higher reservoir temperatures and could be produced by conventional techniques, but the recovery rates would be less than the unconventional Canadian techniques (about 8% versus up to 90% for surface mining and 60% for steam assisted gravity drainage).