* Shares down 0.8 pct after hours
* U.S. oil and gas production fell throughout 2008
* Investors looking for updates from Conoco, Marathon (Adds analyst comment, share price, details on refining)
By Braden Reddall
SAN FRANCISCO, Jan 8 (Reuters) - Chevron Corp (CVX.N) expects its fourth-quarter earnings to be significantly lower than the previous quarter due to the impact of lower energy prices on its exploration and production business.
The second-largest U.S. oil and gas company also said on Thursday its U.S. oil-equivalent production in October and November was 608,000 barrels per day, down from 647,000 the previous quarter and 730,000 in the fourth quarter of 2007.
Chevron shares fell 0.8 percent to $73.62 in after-hours trading, having closed 0.4 percent higher.
On the downstream side, Chevron said refining margins fell sharply in December across its reported regions compared with the previous two months, when they turned negative in Latin America.
U.S. crude oil prices CLc1 averaged about $59 a barrel in the fourth quarter, down by a third from the year before and well below the $147 record seen in July, and these fluctuations have made the refining business less predictable.
"Refining has been kind of Jekyll and Hyde for everybody from one month to the next," said Brian Youngberg, senior energy and utilities analyst at Edward Jones.
Because market conditions had changed significantly, Chevron delayed the unveiling of 2009 capital spending plans until later this month from December. It made $15.8 billion in capital and exploratory expenditures in the first nine months of 2008, out of $22.9 billion budgeted in December 2007.
Youngberg said he would be looking out for possible cuts to 2009 spending plans, even though the oil majors had so far avoided any drastic curtailing of projects.
Rex Tillerson, chief executive of Exxon Mobil Corp (XOM.N), said on Thursday the U.S. oil industry leader was sticking with its $125 billion capital spending budget over the next five years, despite all the market turmoil. [ID:nN08542457]
In line with troubles throughout the petrochemical industry, Chevron said its chemicals segment would see fourth- quarter earnings decline due to lower volumes.
Chevron said international oil-equivalent production in the first two months of the quarter rose to 1.92 million barrels per day from 1.80 million the prior quarter and it expects upstream earnings to benefit by about $625 million from an asset-exchange transaction, without giving details.
But the company also said charges related to corporate and other activities would be well above the high end of its standard guidance of $250 million to $300 million.
Analysts had been expecting a fourth-quarter profit of $3.66 billion, or $1.84 per share, on revenue of $59.2 billion, according to averages on Reuters Estimates. The company had reported a profit of $2.32 per share a year before.
"The quarter's going to be OK -- people weren't expecting a whole lot -- but it's going to come in weaker than expected," Youngberg said.
The San Ramon, California-based company will report on Jan. 30, the first results for new chief financial officer Patricia Yarrington, who took over from Steve Crowe at the start of this month.
Although Chevron shares have recovered from a two-year low of $55.50 in October, they are still down 10 percent since the start of the fourth quarter, compared with a 15 percent decline in the Chicago Board Options Exchange's oil index .OIX. (Reporting by Braden Reddall; Editing by Andre Grenon)