Definitions and explanatory notes

Statistics published in this Review are taken from government sources and published data. No use is made of confidential information obtained by BP in the course of its business

Conversion factors

The conversion factors cover calculation between weight, volume and calorific measures. They provide data for crude oil, products, natural gas, LNG, electricity and solid fuels.


Generally taken to be those quantities that geological and engineering information indicates with reasonable certainty can be recovered in the future from known reservoirs under existing conditions.

The total oil reserves estimates have been compiled using a combination of primary official sources, third-party data from the OPEC Secretariat, World Oil, Oil & Oil & Gas Journal and an independent estimate of Russian reserves based on official data and Chinese reserves based on official data and information in the public domain. Canadian oil sands 'under active development' are an official estimate. Venezuelan Orinoco Belt reserves are based on the OPEC Secretariat and government announcements.

The data series for proved oil in this year’s Review does not necessarily meet the definitions, guidelines and practices used for determining proved reserves at company level, for instance, as published by the US Securities and Exchange Commission nor does it necessarily represent BP’s view of proved reserves by country.

The total natural gas reserves estimates have been compiled using a combination of primary official sources and third party data from Cedigaz and the OPEC Secretariat. The data series for proved gas reserves in this years Review does not necessarily meet the definitions, guidelines and practices used for determining proved reserves at company level, for instance as published by the US Securities and Exchange Commission nor does it necessarily represent BP’s view of proved reserves by country.


Includes data from Federal Institute for Geosciences and Natural Resources (BGR) Energy Study 2017.

Reserves-to-production (R/P) ratio

If the reserves remaining at the end of any year are divided by the production in that year, the result is the length of time that those remaining reserves would last if production were to continue at that rate.


Annual changes and shares of total in the tables for oil consumption, production, refining and trade movements could be calculated on either a volume (barrels per day) or on a weight (tonnes) basis. This year we have elected to calculate growth rates based on the data cited in the table. Percentages have been calculated before the rounding of actuals.


This year’s Statistical Review introduces two changes in how oil and gas are reported in energy units. First, primary consumption of energy from oil is now reported in tonnes of oil equivalent where one tonne of oil is defined as 10 Gcal (gigacalories) or 41.868 GJ (gigajoules). Second, the tables now report natural gas volumes in terms of a standardized gas at a temperature of 15˚C and a pressure of 1013 mbar with a gross calorific value of 40 MJ (megajoules) per cubic metre.

Fuels used as inputs for conversion technologies (gas-to-liquids, coal-to-liquids, and coal to gas) are counted as production for the source fuel and the outputs are counted as consumption for the converted fuel.

Primary energy consumption is reported in net terms. The gross calorific value to net calorific value adjustment is fuel-specific.

The primary energy values of nuclear and hydroelectric power generation, as well as electricity from renewable sources, have been derived by calculating the equivalent amount of fossil fuel required to generate the same volume of electricity in a thermal power station, assuming a conversion efficiency of 38% (the average for OECD thermal power generation).

The Other renewables table shows consumption of commercial electricity produced from renewable sources. Electricity from renewable sources is converted to tonnes of oil equivalent following the same methodology used for nuclear and hydroelectricity and is included in the primary energy consumption calculation.

Biofuels consumption continues to be included in oil consumption data (see footnotes to oil consumption table).

Rounding differences

Because of rounding, some totals may not agree exactly with the sum of their component parts.


Metric equivalent of tons.

Regional definitions

Country groupings are made purely for statistical purposes and are not intended to imply any judgment about political or economic standings

North America

US (excluding US territories), Canada, Mexico


Atlantic islands between the US Gulf Coast and and South America, including Puerto Rico, US Virgin Islands and Bermuda.

Central America

Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama

South and Central America

Caribbean (including Puerto Rico and US Virgin Islands), Bermuda, Central and South America.


European members of the OECD plus Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, the former Yugoslav Republic of Macedonia, Georgia, Gibraltar, Latvia, Lithuania, Malta, Montenegro, Romania and Serbia.

Commonwealth of Independent States (CIS)

Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russian Federation, Tajikistan, Turkmenistan, Ukraine, Uzbekistan.

Middle East

Arabian Peninsula, Iran, Iraq, Israel, Jordan, Lebanon, Syria.

Northern Africa

Territories on the north coast of Africa from Egypt to Western Sahara.

Eastern Africa

Territories on the east coast of Africa from Sudan to Mozambique. Also Madagascar, Malawi, Uganda, Zambia, Zimbabwe.

Middle Africa

Angola, Cameroon, Central African Republic, Chad, Democratic Republic of Congo, Republic of Congo, Equatorial Guinea, Gabon, Sao Tome & Principe

Western Africa

Territories on the west coast of Africa from Mauritania to Nigeria, including Burkina Faso, Cape Verde, Mali and Niger.

Southern Africa

Botswana, Lesotho, Namibia, South Africa, Swaziland.

Asia Pacific

Brunei, Cambodia, China †, China Hong Kong SAR*, China Macau SAR*, Indonesia, Japan, Laos, Malaysia, Mongolia, North Korea, Philippines, Singapore, South Asia (Afghanistan, Bangladesh, India, Myanmar, Nepal, Pakistan and Sri Lanka), South Korea, Taiwan, Thailand, Vietnam, Australia, New Zealand, Papua New Guinea and Oceania.

† Mainland China
* Special Administrative Region


Australia, New Zealand.

OECD members (Organization For Economic Co-operation and Development)

Europe:Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Luxembourg, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, UK.
Other member countries
: Australia, Canada, Chile, Israel, Japan, Mexico, New Zealand, South Korea, US.

OPEC members (Organization of the Petroleum Exporting Countries)

Middle East: Iran, Iraq, Kuwait, Qatar, Saudi Arabia, United Arab Emirates.
North Africa: Algeria, Libya.
West Africa: Angola, Equatorial Guinea, Gabon, Nigeria.
South America: Ecuador, Venezuela.

European Union members

Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Republic of Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, UK.

Non-OECD (Organization for Economic Co-operation and Development)

All countries that are not members of the OECD.

Quoting from the Statistical Review

Publishers are welcome to quote from this document provided that they attribute the source to the BP Statistical Review of World Energy June 2018. However, where extensive reproduction of tables and/or charts is planned, permission must first be obtained from:

The Editor, BP Statistical Review of World Energy
BP p.l.c
1 St James's Square


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