singapore nov 28 reuters  abu dhabi national oil company adnoc will cut 5 of the december crude oil supply to some termlifters in asia but will provide full contractual volumes in january five sources with knowledge of the matter said on monday the oil producer cited the operational tolerance clause which can adjust loading volumes by typically plus or minus 5 for logistical reasons the people said adnoc exports the bulk of its crude to asia and its grades include murban umm lulu das and upper zakum the cut comes as the organization of the petroleum exporting countries and their allies a group known as opec started to trim output by 2 million barrels per day from november aiming to shore up oil prices the output cut has to be reflected in the market and it makes sense that oil producers want to hold off selling at such oil prices a singaporebased trader said benchmark brent crude and wti prices tumbled to 11month lows on monday read more spot premiums of middle eastern crude oman dubai and murban slid this month as market sentiment soured amid oversupply fears opec is due to hold a meeting in vienna on dec4 adnoc does not comment on commercial matters