International natural gas and oil reserves

The Earth's oil and natural gas reserves

Oil and natural gas are fossil fuels that were formed over millions of years from organic material. They are created under high pressure and temperatures in deep geological layers, with oil usually forming from decomposed plants and microorganisms, while natural gas is a by-product of these processes. Oil and natural gas are often found together in their deposits. Natural gas collects in the pores of the rock and can thus form a layer above the oil.

Regions without geologically suitable deposits are spread across large parts of Europe, Australia, and Southeast Asia. In Africa, there are hardly any oil deposits south of the Sahara.

Conventional and unconventional deposits

Conventional deposits are geologically structured in such a way that oil and gas can flow relatively easily from porous rock into a reservoir formation and be extracted via boreholes. Typical examples include sandstone layers or limestone covered by impermeable rock layers. Extraction is technically simpler and economically efficient in these cases.

In unconventional deposits, oil and gas are not neatly contained. They are trapped in dense sandstone or shale, for example, and have no natural barrier above them. Extraction requires special techniques such as hydraulic fracturing (fracking) or horizontal drilling.

• Shale gas and shale oil: trapped in dense clay shales
• Tight gas: gas in very low-porosity sandstones
• Oil sands: bituminous sandstone deposits (e.g., Canada)

The Middle East has the highest concentration of oil and natural gas, mainly in conventional deposits. Shale oil and unconventional gas dominate in North America. In Europe and Australia, on the other hand, there are hardly any conventional deposits.

Oil reserves by country

The largest proven oil reserves are located in the Middle East, particularly in Saudi Arabia, Iraq, Kuwait, the United Arab Emirates, and Iran. Venezuela also has significant reserves of heavy oil. The US and Canada have significant shale oil reserves. Russia and Kazakhstan also have large conventional deposits. In Africa, Nigeria, Angola, and Libya stand out.

International natural gas reserves total 1.697 trillion cubic meters. Venezuela accounts for the largest share, at around 18 percent. The figure for the US is striking here. While around 38.21 billion barrels were still available in 2021, an average of 7.10 billion barrels per year have been produced in recent years and sold to other countries, rather than being used domestically. This means that, mathematically speaking, the recoverable natural gas reserves will be exhausted in just 5.4 years.

All figures refer to the year 2021. The annual production data is an average of the last 3 years available to us. The production volumes relate not only to pure crude oil, but also to NGLs, other liquid fuels and bio-components. The figures are therefore higher than those of the EIA, which only include crude oil and condensates from production.

Natural gas reserves by country

Natural gas is distributed geographically in a similar way to oil, but there are differences in terms of quantity. The amount of remaining and recoverable natural gas reserves was recently estimated at around 206.683 trillion cubic meters. Russia has the largest share of all countries, with around 23 percent. Large gas fields can also be found in Turkmenistan, Australia, and North Africa.

Here, too, the remaining quantity in the United States is striking: natural gas reserves amount to 13.402 trillion cubic meters, of which an average of 1.023 trillion are extracted each year. This means that natural gas will also be depleted in less than 14 years. China, Canada, and Australia also still have relatively large reserves, but the end of production possibilities is already in sight.

The concept of "recoverable reserves"

The reserves stated do not refer to the total amount of natural gas and oil available in a country, but to a recoverable amount. As can be seen from the example of the USA, the figures are far from sufficient to fulfill, for example, the supply commitments just made to the European Union. However, "recoverable" refers only to the realistic extraction of raw materials from today's perspective. Market prices and technology play a particularly important role in this, as they determine whether such extraction makes economic sense at all.

If extraction technology improves, natural gas and oil that are more difficult to reach can be accessed more easily. This increases the amount of recoverable reserves because more of the oil that is actually available is now counted as recoverable. If the market price rises, extraction can also cost more. This also increases the recoverable amount. Against this backdrop, the deal between the US and the EU takes on a completely different light: the US must either raise prices dramatically or obtain oil and natural gas at lower prices elsewhere. The US seems to see a solution to this dilemma in Venezuela and Greenland.

No official data for Greenland

According to geological estimates, Greenland has reasonably large but as yet undiscovered reserves of oil and natural gas, based solely on geophysical models. No commercial fields have been developed to date. The total amount of oil equivalents in the Northeast Greenland Basin is estimated at between 28 and 31 billion barrels, depending on the source. The estimated natural gas reserves are around 4 trillion cubic meters.

There is a purely formal reason why Greenland does not appear in our table. The table only includes confirmed and recoverable quantities. Since Greenland lies under a thick layer of ice and large parts of the country are virtually inaccessible, oil fields have never been confirmed and their economic exploitation would also be highly questionable. However, this may change in the coming years.

Occurrence by crude oil type

Crude oil can be classified into different types according to density and sulfur content, which have different processing requirements and uses. Some oil deposits are restricted in their use and are only suitable for certain refining processes. API° is a unit of measurement for the density of crude oil. It indicates how light or heavy a crude oil is in comparison to water: the higher the number, the lighter the oil.

• Light oil (API° 37-45) is liquid and is suitable for direct use in the production of gasoline and diesel.
• Medium oil (API° 22-36) also produces fuels, but must be partially processed.
• Heavy oil (API° 10-22) and extra heavy oil/bitumen (API° <10) are viscous and must be extensively refined for fuel production. They are often used for heavy oil, asphalt, or synthetic products. The sulfur content also distinguishes sour oil (>1% sulfur), which must be deacidified before use, from sweet oil (<0.5% sulfur), which can be refined directly.

Data sources

United States, Office of Public Affairs, 2021)
Organization of the Petroleum Exporting Countries (OPEC, 2021)
U.S. Energy Information Administration (eia)

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