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Conventional Oil

Conventional Oil refers to oil that is produced from reservoirs using traditional drilling, pumping and compression techniques.


What is Conventional Oil?

Oil is a hydrocarbon formed over thousands of years from the decomposition of dead plants and organisms. Intense heat and pressure on this material triggers a reaction, which leads to the creation of oil.1

Conventional oil is a term used to describe oil that can be produced (extracted from the ground) using traditional drilling methods.  It is liquid at atmospheric temperature and pressure conditions, and therefore flows without additional stimulation.  This is opposed to unconventional oil, which requires advanced production methods due to its geologic formations and/or is heavy and does not flow on its own.

You may have heard of these terms used to distinguish different types of oil:

  • Light vs. Heavy– this refers to the density of oil and its ability to flow.  Lighter oil can be refined with minimal processing due to higher fractions of light hydrocarbons.
  • Sweet vs. Sour – this refers to the sulphur content of the oil, sulphur must be removed prior to refining.  When oil has sulphur greater than 0.5% it is referred to as “sour.”

Because of these variations, oil quality is a spectrum and the distinction between conventional and unconventional is not always black and white. Generally, however, if traditional drilling techniques are used in the oil production it is considered conventional regardless of its physical properties.

Conventional oil is produced using drilling technologies that utilize the natural pressure of an underground reservoir.  Production of a conventional oil well has four main phases2:

  • Exploration:Geological exploration is a series of technologies that are used by geologists and geophysicists to predict the location and extent of underground oil
  • Drilling:Once a reservoir has been located with sufficient certainty, a drilling rig is used to bore a hole from the surface to the oil reservoir.  Piping is then inserted, allowing the oil to be brought to the surface.  Some of the oil in the reservoir will be produced using the natural pressure of the reservoir.
  • Pumping:Gradually the pressure of the well will decrease as oil is produced. At this point a pump will be connected to allow the remaining oil to be extracted.
  • Abandoning: After all the economically viable oil has been extracted from the well, the well is filled with cement to prevent any hydrocarbons from escaping and a special cap is placed over it to protect the area3.



Conventional oil tends to be less expensive and complex to extract than unconventional oil due to the routine nature of the production techniques.  This oil is also the most valuable in global markets because it requires the smallest amount of processing prior to refining to create value-added products. Consequently, many of our global conventional oil supplies have already been extracted, limiting the availability of these source for future extraction3.

Generally, drilling and well abandonment are well-understood and regulated processes but there are always risks with such industrial operations. In drilling, pressure must be regulated carefully to avoid accidents and immediate environmental impacts like land disturbance must be carefully monitored.  After abandonment, well leaks can occur if improper procedures were taken.

As with all fossil fuel production, there are also concerns with greenhouse gas emissions from their combustion4.

Dive deeper

Recent blog posts about Conventional Oil

External resources


International Association of Oil & Gas Producers


International Energy Agency

Organization of the Petroleum Exporting Countries

World Petroleum Council

Oil and Gas Council


US Oil & Gas Association

Illinois Oil & Gas Association

Society of Petroleum Engineer

The Petroleum Marketers Association of America

National Petroleum Council



BMI Research

The Petroleum Institute

University of Calgary

The Oxford Princeton Programme

University of Leeds

University of Dundee

British Columbia Institute of Technology

Canadian Energy Research Institute

Montan Universitat

Oil Center Research

Research Institute of Petroleum Industry

Politecnico di Torino


Universita Degli Studi Di Perugia


SPE Journal

Journal of Petroleum Technology



The virtual Geology Department Canda

Drilling Info

Technology Review (MIT) – Power and Politics in World Oil
The Economist – Oil and Gas
Global Policy Forum – Oil and Natural Gas in Conflict
Columbia – Center on Global Energy Policy
World Bank – The Great Plunge in Oil Prices: Causes, Consequences and Policy Response
American Petroleum Institute – Industry Economics
Oil and Gas Journal – Economics and Oil Market News
Oil and Gas UK – Economic Report 2014

OPEC Monthly Oil Market Report

Platts Real Time Oil Market Data

TEEIC – Potential Impacts of Oil and Gas Production
Kharaka and Dorsey – Environmental issues of petroleum exploration and production
UNESCO – Environmental Impacts of the Oil Industry
Scottish Government Fisheries Research Center – Environmental Impacts
State of the Environment Norway – Environmental Impacts of Oil and Gas activities
National Oceanic and Atmospheric Administration – Effects of Oil and Gas Activities in the Arctic Ocean
IHS – Oil and Gas
Oil and Gas Financial Journal – Analysis
Net News Ledger – Business Analysis
US EPA – Health effects of pollutants emitted from oil and natural gas prod. facilities
Earthworks – Oil and Gas Health Effects
Worcester Polytechnic Institute – The Health Effects of Oil Contamination
Journal of Environmental Sustainability – Towards Sustainability in the Oil and Gas Sector: Benchmarking of Environmental, Health, and Safety Efforts 
Ceres – Oil & Gas Producers
Castagra – Voluntary Sustainability Reporting
GreenBiz – Is there a greener side to Drilling for Oil?
Deep Blue Library – Oil Companies and Sustainability: More than just an Image?
Unep and The E&P Forum – Environmental Management
Financial Times – Oil – The big Drop

International Energy Agency (IEA) Oil Overview – Types of Crude Oil 

  1. BP PLC (n.d.). How oil and gas form. 
  2. Chestnut Exploration (n.d.). Conventional versus unconventional oil. 
  3. Alberta Energy Regulator (n.d.). Why are wells abandoned.
  4. United States Environmental Protection Agency (n.d.). Global emissions by gas.