VIENNA — Organization of the Petroleum Exporting Countries (Opec) expects demand for its crude to be lower than expected in 2013 because of higher supply from rival producers, indicating inventories could build up substantially if the producer group maintains current output. The Opec's monthly report indicated world supply will comfortably outstrip demand in the first half of this year, even after top exporter Saudi Arabia cut its production in December to fend off a supply overhang and defend prices well above $100 a barrel. It forecast demand for Opec crude this year would average 29.65 million barrels per day, down 100,000 bpd from last month. This is less than Opec's December production of 30.37 million bpd as estimated by secondary sources. Demand for Opec crude will average 29.07 million bpd in the first half of 2013, the report estimated, implying inventories could build up by about 1.3 million bpd should Opec maintain December's output rate. Opec has a target for its 12 members to produce 30 million bpd. With prices above Riyadh's preferred $100 but with expectations of slower demand in early 2013, Opec at a meeting in December left the target unchanged, leaving the door open to informal supply tweaks depending on demand. Saudi Arabia told Opec it produced 9.025 million bpd in December, down from 9.49 million bpd in November, confirming figures provided last week by an industry source familiar with Saudi policy. Record Saudi output last year of up to 10 million bpd helped to cushion the impact of Western sanctions on Iran over its nuclear program by helping to bring prices down from a 2012 high of $128 in March. The other significant cutbacks in Opec output in December were due to technical and political setbacks in Iraq, the world's fastest-growing exporter, and the impact of the sanctions on Iran. Meanwhile, the price of oil jumped above $94 a barrel Wednesday after an unexpected drop in US crude supplies. Benchmark oil was up 92 cents to $94.20 a barrel at midday on the New York Mercantile Exchange. Oil supplies fell by 1 million barrels, or 0.3 percent, to 360.3 million barrels last week. The drop was due mainly to a decline in imports. Gasoline supplies grew less than expected as refineries slowed output. Still, supplies of oil and gasoline remain above average for this time of year, with crude inventories nearly 9 percent higher than a year ago and gasoline levels more than 3 percent higher. US production of crude, at more than 7 million barrels a day, is the highest in 20 years. Brent crude, used to price international varieties of oil, was up 37 cents to $110 per barrel on the ICE Futures exchange in London. Trading will be watching for the latest reading on China's economic growth Friday and contentious negotiations in Washington over the nation's borrowing limit. — SG/Agencies