Also a western trader may have sold a cargo also at plus 18 cents to a US major. Traders agreed that sentiment for Oman was firm amid tight supplies of medium-heavy grades because of output cuts agreed by major producers and many expected a deal at plus 20 cents in the near future.

Some, however, expect the fairly large availability of Oman crude in the spot market to cap any sharp rally above 20 cents. Sellers disagreed. "Chinese and Korean buyers were in the market (on last Tuesday) and sellers have toughened their stance," said a potential seller.

He assessed offer levels at or above plus 22 cents. The view that supply of Oman crude is ample is supported bythe fact that Japanese traders are not desperate to buy Yemeni Masila crude. Potential buyers of Masila said they had submitted their bids, but were not intent on buying Masila as they believed the price would be high, and Oman supply to be ample. "Yes we did submit our bid, but we are not seriously interested in getting (Masila)," said a trader for a Japanese refiner, adding that he may decide not to buy Masila.

While many expect the term formula for May will be up from April's minus 29 cents to Dated Brent, one trader said he had heard that a bid as low as minus 40 cents had been submitted, and that the highest bid was a discount in the teens. On the regional front, China National United Oil Corp has notified Japanese buyers of Daqing that the crude's availability will be about 4,00,000 tonnes, less than their nominated volume of about 4,60,000 tonnes, traders said.

The allocation notice came a little later than usual, and contained no explanation of why the allocation had been cut, traders said. Buyersources said, however, the cut was not too large and it would not have a large effect on the supply and demand balance for heavy sweet crudes.