- The country's economy is heavily dependant on hydrocarbons, which account for 30 percent of gross domestic product, nearly 75 percent of government revenues, and over 90 percent of foreign exchange earnings, according to the U.S. Energy Information Administration (EIA).
- Citizens have renewed calls for southern Yemen, which produces most of the country's crude oil, to go back to its independent status before unity with the north in 1990.
- Yemen had proven oil reserves of around 3 billion barrels as of Jan. 1, 2012, according to the EIA, sourcing Oil and Gas Journal. The country's oil is generally light and sweet.
- Oil reserves and production are sourced from two areas: Marib-Jawf basin in the north, and Say'un-Masila basin in the south. The government estimates Masila holds about 84 percent of the national total.
- Daily oil production fell to 170,000 barrels per day (bpd) in 2011, sharply down from the estimated 259,000 bpd for 2010. Yemen's oil output has been on a steady decline since 2001, when it hit a peak of 440,000 bpd. But the political turbulence of 2011 has pushed the output below 200,000 bpd, EIA says.
- Oil is transported from Masila to Ash Shahir by a 90-mile pipeline with a capacity of 300,000 bpd, while the 130-mile Shabwa-Bir Ali pipeline carries up to 135,000 bpd from the Ayad-Shabwa block to the Bir Ali terminal on the Gulf of Aden.
The 270-mile Marib-Ras Isa pipeline has a capacity of 400,000 bpd and transports oil from the Marib basin to the Ras Isa offshore export terminal on the Red Sea.
- Yemen has five oil export terminals. Ras Isa is the main crude terminal offshore in the Red Sea. But most of the crude it loads is usually shipped to the Aden refinery on the Gulf of Aden.
The Bir Ali facility handles crude from Shabwa, while Ash Shihr is now operated by state-owned PetroMasila, which took over from Canada's Nexen after the government refused to renew the company's operating licence.
- The state-operated Aden Refinery Company, which also manages Yemen's strategic fuel reserves, is an old refinery with a capacity of 130,000 bpd, while the Yemen Refinery Company's newer Marib can refine 10,000 bpd of crude.
- Yemeni and Chinese officials have discussed upgrading the ageing Aden refinery to process Kuwaiti and Masila crude, which may cut Yemen's fuel imports and boost exports.
- Yemen is a regular buyer of oil products, with imports of around 30,000 tonnes per month, but fuel shortages have forced the country to import more since 2011.
Saudi Arabia has donated 3 million barrels of crude oil to Yemen in 2011. The top oil exporter also donated at least 500,000 tonnes of fuel to its impoverished southern neighbour earlier this year.
- An estimated 3.5 million bpd passed through the narrow Bab al Mandab strait between Yemen and Djibouti in 2010, according to the EIA.
- Disruption to the narrow shipping lane could stop Gulf oil and LNG tankers from passing through the Suez Canal to the Americas or Europe.
It could also prevent oil tankers from unloading at Egypt's Ain Sukhna terminal near the southern entrance of the Suez Canal which feeds crude to Sidi Kerir on the Mediterranean coast of Egypt via the Sumed pipeline.
About half of the Sumed crude comes from Saudi Arabia and is mostly shipped to Europe, according to the pipeline operator.
- Yemen has proven gas reserves of 16.9 trillion cubic feet as of January 2012, according to the Oil and Gas Journal.
- Most of the gas is found in the Marib-Jawf oilfields and it is mostly reinjected to enhance oil recovery. Gas production has been in decline since 2005.
- Yemen LNG's export facility at Balhaf, which opened in 2009 and is led by French oil major Total with three South Korea companies holding stakes, is the largest-ever industrial project in Yemen.
- The $4.5 billion Yemen LNG project has two production trains with a combined capacity of 6.7 million tonnes per year, supplying mainly to Asia, and then to Europe and Americas.
- One of the pipelines feeding gas from the Marib field to the LNG plant was also attacked in 2011.
FOREIGN COMPANIES INVOLVED
According to the EIA, nine international oil companies operate in Yemen's 12 main producing blocks.
According to Yemen's Petroleum Exploration and Production producing companies are: Canada's Calvalley Petroleum, U.S.-based Hunt Oil and Occidental Petroleum, Norway's DNO, Korean National Oil Company, France's Total, Austria's OMV, Britain's Dove Energy, Canada's Nexen.
Kuwait Energy, India's Reliance, China's Sinopec and Italy's Eni are among the companies which are in exploration stage.
Sources: U.S. Energy Information Administration (EIA), BP Statistical Review, Reuters news, European Union energy portal, Yemen's Petroleum Exploration and Production Authority, company websites.