ConocoPhillips (NYSE: COP), is preparing to sell all of its assets in one of Africa's leading producers of crude oil -- Nigeria.

The company's sale is expected to include all of ConocoPhillips' on-shore and off-shore oil and gas fields, including a stake in its Liquefied Natural Gas Brass facility, reported Reuters Tuesday citing unnamed sources.

The company holds a 20 percent stake in three oil fields operated by Italian oil company Eni near the coast of Nigeria's oil-rich delta.

ConocoPhillips holds a minority stake in operations developing 20 million barrels of oil a day and 141 million cubic feet of natural gas a day in Nigeria, said the company's website citing 2010 production numbers.

The company also holds interests in other African countries including Libya, Algeria and Angola.

The company's energy production in Africa however is much lower thanin Alaska, the United States and the Middle East.

According to a 2011 annual report, the company's African operations constituted 4 percent of its total production, and 5 percent of its energy reserves. 

In 2011, the company produced 1.6 billion barrels of oil and natural gas.

Nigeria is home to Africa's second-largest oil reserves and as of 2011, has an estimated 37.2 billion barrels in proven reserves, reported the U.S. Energy Information Administration.

ConocoPhillips did not return requests for comment by press time.

In Tuesday trading in New York, ConocoPhillips rose $1.08 a share to $54.44.