Danish shipping and oil company Maersk has told at least one buyer it will delay September and October-loading shipments of its al Shaheen crude, a source at the buyer said on Wednesday.

"We were contacted and asked to postpone the loading days," the source said.

Work on a project to expand the field's capacity may have led to a delay of a day or two in the loading programme for the heavy sour grade, a separate industry source said.

"It's a massive project and there's a lot of activity at the field," he said. The project aims to expand production at the field to 525,000 barrels per day from the end of this year.

Maersk, which has had operations in Qatar since 1992, owns and operates the al Shaheen field but gives back an unspecified amount of oil to state oil firm Qatar Petroleum (QP).

But several Middle East-based crude market traders said there has been talk of production problems at the field, which has lead to a drop in the volumes of al Shaheen available on the spot market for November, but this could not be confirmed.

In its regular monthly tender for the heavy sour grade, QP offered two 600,000-barrel cargoes of al Shaheen crude for November loading, traders said earlier this week, its lowest offering in six months.

Maersk, which also sells on the spot market, sold two front-month November-loading al Shaheen cargoes at 30-cent premium to Dubai quotes, sharply up from discounts of 80 cents fetched last month for similar October-loading cargoes, traders said. "It's as high as Oman," said one trader.

Oman, the Middle East sour benchmark crude, usually sells higher than al Shaheen on the spot market, but the alleged production problems and a drop in volumes were boosting sentiment for the grade, traders said.-Reuters