W. Africa Crude-Nigerian grades edge lower

March 4 (Reuters) - Nigerian crude differentials edged lower on Tuesday as March cargoes continue to overhang.

Forcados has dipped to around dated Brent plus $2.50, Bonga to around dated plus $2.50-$3.00, and Qua Iboe to around dated Brent plus $1.50, a trading source said.

Around 10-15 cargoes of Nigerian crude remain available for March, the source added, little changed from other traders' recent indications.

Meanwhile, Angola's March programme was heard to have sold out.

Angolan Dalia crude was heard on offer around dated Brent plus $1.50.

On Monday, Nigerian Amenam was heard on offer at dated Brent plus $1.55, and EA at dated Brent plus $5.25, according to a trading source.

Also on Monday, Angolan Plutonio was on offer at dated Brent plus $1.30 and Clov at dated Brent plus $2.50.

In other news, Nigeria's Seplat Energy plans to invest up to $320 million in new wells and infrastructure this year, aiming to more than double its oil output to as much as 140,000 barrels per day following its acquisition of Exxon Mobil's Nigerian assets.