August-loading Oman crude is feeling the pressure of rival Russian Urals crude, a competing grade, traders said on Tuesday.
Traders said at least three to four cargoes of July-loading Urals have been offered to Asian buyers.
"Spot premiums for Oman would be pressured by Urals," said a trader at South Korean refiner.
August-loading Oman crude was assessed at MOG plus 8-13 cents a barrel on Tuesday, in line with Monday but down from MOG plus 10-15 cents on Friday.
Traders said Urals was being offered at more than $2.00 per barrel over Dubai, on a cost-and-freight basis, up from $1.80 for May-loading cargoes.
But they said they expected the price to weaken in line with the narrowing spread of Brent/Dubai exchange for swaps (EFS).
The August Brent/Dubai EFS stood at about $2.66/$2.72 on Tuesday, slightly firmer than Monday following a firmer tone in the Brent futures market, but inside a week-earlier $2.89/$2.97.
Vitol was heard to have bought six partial cargoes, of 25,000 barrels each, of August-loading Dubai crude at $33.48 a barrel on Monday. It took four lots from Phibro and one each from ChevronTexaco and BP.
Traders said the latest deals took Vitol's purchases of August Dubai to 225,000 barrels through partials trading. It bought two partials from BP and one from Phibro at $35.40 a barrel on Thursday.
Trader said Nippon Oil bought one million barrels of July-loading Nile Blend from Chinaoil at around $3.30/$3.40 a barrel over the Indonesia Crude Price (ICP) for Minas, on a cost-and-freight basis.
In the regional sweet crude market, ChevronTexaco was heard offering a partial cargo of July-loading Minas at ICP plus $1.90 a barrel.