Oil Reserves – How Long Will Conventional Oil Last?

In the last 40–50 years we have had a discussion about how long the oil reserves will last and the famous geologist M. King Hubbert predicted in 1956 that oil production would peak in the United States between 1965 and 1970, and later Colin Campbell predicted that world production would peak in 2007 (see the Peak Oil movement). There is, however, a great deal of uncertainty in the estimation of reserves since this will depend on advancements in exploration technology as well as production efficiency.

The price of oil and taxation policies will also determine which type of oil accumulations can be exploited economically and thus reckoned as reserves. At present the world reserves are estimated to be 1.2 × 1012 bbl 2 × 1011m3 and nearly 60% of this is located in the Middle East.

Europe has only got 1% and the whole of Asia about 3%. Canada had up to recently very small reserves but after the heavy oil and tar sand in Alberta was included it has now nearly 15% and is second only to Saudi Arabia. If oil shales were to be included, however, the USA would be the country with the largest reserves. The world consumes about 85 million bbl/day 85 × 106 bbl/day ; the US consumption (20.7× 106 bbl/day makes up nearly 25% of that. The most important producers are Saudi Arabia (10.2 × 106 bbl/day) and Russia (9.9 × 106 bbl/day).

The US is also a major producer (7.5 × 106 bbl/day) but this is still only about 37% of the country’s consumption. China has become a major importer of oil with a consumption of 7.6 × 106 bbl/day, while their production is 3.9 × 106 bbl/day. It is clear that consumption of oil in Asia will rise and it will be very difficult to meet this demand. Norway’s oil production was 122 million Sm3 in 2008 and about the same amount of gas. This corresponds to 0.8 × 106 bbl or 2.1 million bbl of oil/day.

However since the domestic consumption is only about 10% of this (0.22 million bbl/day), Norway is a major exporter. It will probably be difficult to meet the demand for conventional oil in the next decades. There are, however, very large reserves of fossil fuels in terms of gas, heavy oil, tar sand and also coal. All these types of fossil fuel can be used for heating and transport. Particularly in North America there is much oil shale and also gas shale. Gas in fine-grained siltstones and shales is expected to be a major source or energy in the years to come. In recent years coal methane and shale gas have become important sources of such energy.

It will probably take a long time before fossil fuels can be replaced by other sources of energy. As the demand increases, oil exploration and production will become more and more sophisticated technologically and also geologically. A broader background in geological and engineering disciplines will also be required to reduce the environmental problems with the exploitation of fossil fuels. Storage of carbon dioxide requires expertise from petroleum geologists. The exploitation and burning of fossil fuels releases large amounts of CO2 into the atmosphere which is an addition to what is part of the natural carbon cycle (Fig. 1.14). The CO2 in the atmosphere is dissolved in seawater to H2CO3 and then precipitated as carbonate. Another part is taken up by plants, including algae, and may be stored as reduced carbon.