The African continent is home to five of the top 30 oil-producing countries in the world. It accounted for more than 8.7 million barrels per day in 2014, which is about 9.4% of world output for the year. This level of production is down somewhat from the heights of 2005 to 2010 when African production topped 10 million barrels per day, including a high of nearly 10.7 million barrels per day in 2010. As of 2015, declines are due mostly to political and civil instability and violence in many of Africa's biggest oil-producing countries.

1. Nigeria

Nigeria produced more than 2.4 million barrels of oil per day in 2014 to rank as the 13th-largest oil producer in the world. The country has produced between 2.1 million and about 2.6 million barrels per day for the last 18 years. Fluctuations in annual oil production, especially since 2005, can be attributed largely to security problems connected to violent militant groups in the country. While Nigeria is home to the second-largest proven oil reserves in Africa, the U.S. Energy Information Administration (EIA) reports that security issues and other business risks in the country have reduced oil exploration efforts.

The state-owned Nigerian National Petroleum Corporation (NNPC) is responsible for regulating Nigeria's oil and gas sector, and for developing its oil and gas assets. The NNPC relies heavily on international oil companies to fund development and provide expertise. Most large onshore oil production operations in the country are organized as joint ventures between the NNPC and private oil firms, with the NNPC as majority owner. Comparatively costly and complicated offshore oil developments are typically organized under production-sharing contracts, the terms of which can be adjusted to provide appropriate incentives to international operators. The largest international oil companies operating in Nigeria include Chevron Corporation, Exxon Mobil Corporation, Royal Dutch Shell plc, Total S.A. and Eni S.p.A.

2. Angola

Angola produced nearly 1.8 million barrels of oil per day in 2014, continuing a period of fluctuating production that began in 2009. Prior to 2009, the country achieved seven consecutive years of production gains in the oil sector, raising the average output from 742,000 barrels per day to nearly 2 million barrels per day. These gains were primarily the result of new production from deepwater oilfields offshore. Most oil production in Angola takes place offshore, as violence and conflict have limited exploration and production activities onshore.

The Sociedade Nacional de Combustiveis de Angola, also known as Sonangol, is Angola's state-owned oil company. It oversees virtually all oil and gas development in the country. Most exploration and production operations in Angola are headed by international oil companies operating in joint ventures or under production-sharing agreements with Sonangol. Some of the biggest oil companies in Angola include Chevron Corporation, Exxon Mobil Corporation, Total S.A., Statoil ASA, Eni S.p.A. and China National Offshore Oil Corporation, also known as CNOOC.

3. Algeria

Algeria produced just over 1.7 million barrels of oil per day in 2014 to maintain its position among the top tier of African oil producers. However, 2014 marks the second consecutive year of falling production in the country, amounting to a total of more than 150,000 barrels per day of lost production. According to the EIA, these declines are primarily a result of delayed investments in new infrastructure and new production projects. In the nine years prior to 2013, Algerian oil production was fairly consistent, averaging around 1.9 million barrels per day. In addition to its substantial oil output, Algeria also ranks as the top natural gas producer in Africa.

Entreprise Nationale Sonatrach is Algeria's state-owned oil and gas company. Under the Hydrocarbon Act of 2005 and its subsequent amendments, Sonatrach must retain a minimum of 51% equity in all oil and gas projects in the country. As of 2014, Sonatrach controls approximately 80% of oil and gas production in the country. International oil companies make up the remaining 20%, albeit through joint ventures and similar arrangements with Sonatrach. International oil majors involved in Algerian oil production include BP plc, Repsol S.A., Total S.A., Statoil ASA, Eni S.p.A. and Anadarko Petroleum Corporation.

4. Egypt

Egypt produced 668,000 barrels of oil per day in 2014, the fourth consecutive year of falling production. Declines totaled about 9.3% during that period, which is especially problematic given the 3% annual growth in oil consumption in the country during the last decade. According to the EIA, the decline in Egyptian production is mostly attributable to maturing oil fields. Exploration activities continue in the country in the hopes of boosting domestic production to keep up with ever-increasing domestic demand.

Egypt's state-owned oil company, Egyptian General Petroleum Corporation (EGPC), controls all oil production in the country. EGPC partners with a number of international oil companies in offshore and onshore production operations in Egypt. Eni S.p.A. and BP plc are major shareholders in offshore Egyptian production assets. The American oil company Apache Corporation is a partner in production assets in Egypt's Western desert.

5. Libya

Libya produced about 516,000 barrels of oil per day in 2014, a decrease of more than 47% from the previous year. This decline was primarily a result of national protests that broke out in 2013. The country saw even more severe disruptions in oil supply during the Libyan civil war in 2011 when production declined from about 1.8 million barrels per day in 2010 to a daily average of 500,000 barrels the next year. Prior to 2011, Libya maintained oil production above 1.7 million barrels per day for six consecutive years. The country contains proven reserves of oil amounting to about 48 billion barrels, which is the most in Africa.

The state-owned National Oil Corporation has controlled the oil and gas sector in Libya for many years. However, the civil unrest in the country has precipitated a power struggle that has yet to be concluded as of September 2015. International oil companies were active in Libyan oil production prior to this period, but the future will remain cloudy until the instability is resolved. International oil companies with operations in Libya include ConocoPhillips Co., Repsol S.A., Total S.A., Eni S.p.A. and Occidental Petroleum Corporation.