NEW DELHI, May 11 (Reuters) - Trader Nexen has sold its first equity cargo of Nigerian Usan oil to India's Reliance Industries, owner of the world's biggest refining complex, for lifting end-May, a trade source familiar with the deal said on Friday.
Reliance's two advanced refineries in western Gujarat state can together process 1.2 million barrels per day (bpd) of oil -- about 28 percent of the country's overall refining capacity.
The complexity of these plants allows the refiner to continuously diversify its crude slate by testing new grades.
Reliance bought 1 million barrels of Usan crude from Nexen at about the official selling price, the trade source said.
No comment was available from Reliance.
Reliance recently made its first-ever purchase of Equatorial Guinea's Aseng oil and Albania's Patos Marinza, data available to Reuters show.
Reliance processed eight new crudes for the first time in the last fiscal year ending March 31 as it always looks for economic feedstock, the company said in its annual report for 2011/12 which is posted on its website.
The Usan oil field off the Nigerian coast is operated by France's Total SA and began production in February.
Nexen has a 20 percent share in the Usan field, located 100 km (62 miles) southeast of the Nigerian coast.