OMV’s quarterly production fell to 304,000 barrels of oil equivalent per day (boed) from 320,000 in the previous quarter, it said in a trading statement, which gave the first detailed indication of how the shortfall is affecting operations.

Libyan production was normal until Feb. 20 and then fell sharply, OMV said. The country produced only 18,700 barrels of oil per day in the first three months of the year, down from 32,800 in the previous quarter.

Libya, at the center of OMV’s expanded North Africa operations, provided a tenth of its global output of 318,000 boed last year.

Production in Yemen has stopped since March 14 due to an attack on an export pipeline, OMV said. Yemen provided 6,600 boe/d last year.

Italian peer Eni’s production fell almost nine percent in the first quarter because of unrest in Libya and it expects its full-year output to be lower, the company said.

Eni, the biggest foreign oil operator in Libya, said it expects its oil and gas output in 2011 to decline following the shutdown of almost all its production facilities there.

Vienna-based OMV has been seeking Saudi and Kazakh oil to make up the shortfall but analysts expect the supply disruption will have hit first-quarter earnings, due for release on May 11.

OMV’s reference refining margin, an indicator of profitability, narrowed to $2.30 per barrel in the first quarter compared to $3.48 in the previous three months. Total refining sales were 4.49 million tons.