SAN RAMON -- Chevron expects its profits for the fourth quarter of 2012 to be "notably higher" than the earnings for the third quarter of 2012, the energy giant said Thursday.

The company's upstream business -- exploration, development and production -- is expected to post higher earnings. Chevron's downstream operations -- refineries, retail outlets and transportation -- also will harvest higher profits.

San Ramon-based Chevron says it will release its fourth-quarter financial results on Feb. 2.

The upstream results are being bolstered by gains on asset transactions and increased production.

Downstream earnings are rising because of timing on costs and revenue. The company said refinery margins eroded.

During October and December, the first two months of the recently completed quarter, crude-input volumes into refineries decreased by 77,000 barrels a day.

The ongoing shutdown of the Richmond refinery's crude unit, hobbled by a disastrous fire in early August, was the primary factor behind the slump in refinery operations.

A return to normal operations at Chevron's refinery in Mississippi following Hurricane Isaac partly offset the decrease in refining activity.

The company's shares rose 0.9 percent to finish at $110.47 during regular-session trading. In after-hours trades, Chevron was up another 0.6 percent. Chevron issued its interim update after the financial markets had closed.

Contact George Avalos at 408-373-3556 or 925-977-8477. Follow him at twitter.com/george_avalos.