Total SA (FP), France’s largest oil company, sold its 20 percent stake in an offshore Nigerian field to China Petrochemical Corp. for about $2.5 billion as part of an asset-disposal program.

The OML 138 block includes the Usan field, which started output in February, Paris-based Total said today in a statement. The asset accounts for about 10 percent of Total’s Nigerian production, which averaged 287,000 barrels a day last year.

The sale is part of Total’s plans to complete $15 billion to $20 billion of asset disposals from 2012 to 2014. China’s state-backed energy companies are seeking new oil and gas reserves abroad to feed the world’s second-largest economy, especially from regions like Africa where government scrutiny is lighter than in North America or Europe.

The sale of a minority stake in the Nigerian block is in line with Total’s policy of actively managing its portfolio, Yves-Louis Darricarrere, head of exploration and production, said in today’s statement.

The Usan field production, whose ramp up was slower than expected, could reach 140,000 barrels a day by the end of the year, Chief Financial Officer Patrick de la Chevardiere said in July. The French company had said it was expecting a peak rate of 180,000 barrels a day.

Total rose as much as 2 percent and was trading 70 cents higher at 37.67 euros as of 3:05 p.m. in Paris.

Total is also searching for a buyer for its southwestern French natural gas network known as TIGF. Current disposals could bring Total about halfway to its target, de la Chevardiere said last month.

Maurel Interest

Beijing-based Sinopec Group has also approached the French oil firm Etablissements Maurel et Prom (MAU), which operates in Gabon, about an acquisition, people familiar with the matter said this month.

Sinopec’s reserves of crude oil declined from 3.3 billion barrels in 2007 to 2.8 billion barrels at the end of last year, enough for nine years of production at 2011 levels, according to data compiled by Bloomberg. Its parent, China Petrochemical, said in January that it will seek to produce 50 million metric tons of crude a year overseas by 2015. Last year, foreign production was 23 million tons.

The Nigerian National Petroleum Corp. is the OML 138 concession holder. Chevron Petroleum Nigeria Ltd. has 30 percent, as does Esso E&P Nigeria (Offshore East) Ltd. Nexen Petroleum Nigeria Ltd. has 20 percent.