Unconventional oil refers to oil resources that are extracted using methods different from traditional drilling techniques. This includes sources like tar sands, oil shale, and tight oil, which require advanced technologies such as hydraulic fracturing or horizontal drilling to access. These methods often involve more complex processes and can have a greater environmental impact compared to conventional oil extraction. The extraction of unconventional oil has become increasingly important as conventional oil reserves decline. Countries like the United States and Canada have invested heavily in these resources to enhance energy security and reduce dependence on imported oil. However, the economic viability and environmental concerns surrounding unconventional oil continue to spark debate.