Editing Petroleum (section)

=== Unconventional oil ===
{{Update section|date=May 2022}}

[[Unconventional oil]] is petroleum produced or extracted using techniques other than the conventional methods. The calculus for peak oil has changed with the introduction of [[Unconventional (oil & gas) reservoir|unconventional]] production methods. In particular, the combination of [[horizontal drilling]] and [[hydraulic fracturing]] has resulted in a significant increase in production from previously uneconomic plays.<ref>{{Citation | date = May 28, 2015 | title = U.S. Crude Oil Production Forecast – Analysis of Crude Types | publisher = U.S. Energy Information Administration | place = Washington, DC | url = http://www.eia.gov/analysis/petroleum/crudetypes/pdf/crudetypes.pdf | access-date = September 13, 2018 | quote = U.S. oil production has grown rapidly in recent years. U.S. Energy Information Administration (EIA) data, which reflect combined production of crude oil and lease condensate, show a rise from 5.6 million barrels per day (bbl/d) in 2011 to 7.5 million bbl/d in 2013, and a record 1.2 million bbl/d increase to 8.7 million bbl/d in 2014. Increasing production of light crude oil in low-permeability or tight resource formations in regions like the Bakken, Permian Basin, and Eagle Ford (often referred to as light tight oil) account for nearly all the net growth in U.S. crude oil production.<br />EIA's latest Short-Term Energy Outlook, issued in May 2015, reflects continued production growth in 2015 and 2016, albeit at a slower pace than in 2013 and 2014, with U.S. crude oil production in 2016 forecast to reach 9.2 million bbl/d. Beyond 2016, the Annual Energy Outlook 2015 (AEO2015) projects further production growth, although its pace and duration remains highly uncertain. | archive-date = November 22, 2019 | archive-url = https://web.archive.org/web/20191122192224/https://www.eia.gov/analysis/petroleum/crudetypes/pdf/crudetypes.pdf | url-status = live }}</ref> Certain rock [[strata]] contain hydrocarbons but have low permeability and are not thick from a vertical perspective. Conventional vertical wells would be unable to economically retrieve these hydrocarbons. Horizontal drilling, extending horizontally through the strata, permits the well to access a much greater volume of the strata. Hydraulic fracturing creates greater permeability and increases hydrocarbon flow to the wellbore.