ConocoPhillips, the No. 3 U.S. oil company, said fourth-quarter production was lower than expected, and refining and marketing margins fell significantly from the third quarter.
The company also said its crude oil sales prices sank during the quarter.
ConocoPhillips said fourth-quarter oil and gas production was similar to the third quarter as lower output from the Timor Sea, continental United States and Libya offset higher output from Alaska and Britain.
The company, which previously forecast production would rise in the fourth quarter, said the resumption of operations at its Prudhoe Bay operations in Alaska was hurt by weather-related transportation delays.
ConocoPhillips did not disclose its actual realized sales prices but said market prices indicate crude oil dips of 14% to 20% and natural gas prices similar to those of the third quarter.
The various benchmark crude oil market indicators were mixed when compared with the year-earlier quarter, while natural gas prices lost nearly half their value.
Among the top U.S. oil and gas producers, ConocoPhillips has the heaviest exposure to natural gas. Natural gas prices have recently plummeted due to unseasonably warm weather in the U.S. Northeast and high inventory levels.
"With a higher exposure to natural gas, they are more leveraged to that downside," said Mercantile Trust energy analyst Gene Pisasale.
Excluding one-time items, ConocoPhillips earned $2.69 a share in the 2005 fourth quarter. Analysts' average forecast for the 2006 fourth quarter is $2.18 a share.
The company said its exploration expenses are expected to be about $350 million before taxes for the quarter. It will also record a $90 million charge as a result of declining well performance and drilling results in the Canadian Rockies foothills.
Its average crude oil refining capacity in the quarter is expected to be in the mid-90 percent range, the company said.
It previously said it plans to take a $200 million charge in the quarter for U.S. marketing assets it is putting up for sale.
ConocoPhillips said results at its midstream and chemicals businesses are expected to be lower than in the third quarter.