Some of the nation's biggest oil companies reported a windfall quarter Tuesday, reflecting the impact of the highest crude oil prices in nearly a decade.

Earnings at

ExxonMobil

(XOM) - Get Report

and

Texaco

(TX) - Get Report

more than doubled, and earnings at

Conoco

(COC.B)

quadrupled. At all three, earnings from exploration and discovery greatly offset the lower earnings from refining, marketing and distribution, where prices did not rise as quickly as the price of crude oil.

Tosco

(TOS)

, the nation's leading oil refiner, also posted a steep increase in earnings, but the numbers missed Wall Street's expectations by 3 cents.

ExxonMobil, the nation's largest oil company, said earnings excluding merger expenses and special items surged to $3.35 billion, or 95 cents a diluted share, compared with $1.61 billion, or 46 cents a diluted share, a year earlier. Revenue rose 42% to $55.08 billion. Wall Street had expected 90 cents a share, according to a

First Call/Thomson Financial

poll.

ExxonMobil's shares jumped 13/16, or 1%, to 80 11/16 in midday trading Tuesday. (ExxonMobil closed up 1 1/8, or 1%, at 81.)

The Irving, Texas-based company said rising crude oil prices, which averaged over $15 more a barrel than in the first quarter of 1999, and a 27% increase in average natural gas prices led to a 248% increase in earnings to $2.75 billion. This helped to offset a drop of 31% to $369 million in the company's refining and marketing, or downstream, earnings.

"Downstream earnings were lower than last year, reflecting the inability to raise product prices in line with rising crude costs," Lee Raymond, ExxonMobil's chairman, said in a statement. "As crude oil prices declined near the end of the first quarter, downstream margins improved sharply."

Crude oil prices have slipped to just above $27 a barrel, after peaking at a nine-year high of $34 a barrel in March on rising global demand and limits on production by oil-exporting countries.

Texaco, the nation's third-largest oil company, based in White Plains, N.Y., said first-quarter earnings rose to $574 million, or $1.05 a share, compared with $199 million, or 35 cents a share, in the year-ago period. The results beat analyst expectations by 7 cents. Revenue jumped 57% to $11.3 billion.

Texaco's shares rose 5/16, or 1%, to 52. (Texaco closed up 1/2, or 1%, at 51 3/16.)

Conoco of Houston beat Wall Street's expectations by a penny, reporting first-quarter earnings before special items of $391 million, or 62 cents a diluted share, compared with $83 million, or 13 cents a diluted share, in the year-ago period. Conoco revenue jumped 63% to $8.69 billion.

Conoco's Class B shares were trading up 3/16, or 1%, at 24 7/16 in morning trading. (Conoco closed up 1/16, or 0.3%, at 24 5/16.)

Tosco of Stamford, Conn., said earnings more than doubled in the quarter to $74.9 million, or 50 cents a diluted share, from $27.9 million, or 18 cents a diluted share, a year ago. Wall Street had, however, estimated earnings of 53 cents a share, according to a First Call/Thomson Financial survey. Sales surged 76% to $4.63 billion.

Tight refining margins hurt the company's retail operations, particularly in the West Coast where the crude oil price increases outpaced the ability of the company to raise prices for refined petroleum.

Tosco was off 7/8, or 3%, at 32. (Tosco closed down 1, or 3%, at 31 7/8.)