Crude Ends at Four-Month High

Updated from 1:15 p.m. EST

Oil prices marched to a four-month high Friday as the impact of this week's geopolitical tension was exacerbated as the February contract approached expiration.

February crude rose $1.52 to $68.35 a barrel, a day after rising $1.10. Front-month crude has risen more than 12% in 2006 amid an influx of speculative money and rising political tensions in Nigeria and Iran. Heating oil futures tacked on 8 cents to $1.87 a gallon.

In Iran, political brinksmanship swirled this week as Western powers sought a U.N. hearing on the country's renascent nuclear ambitions. Iran has recently taken steps to restart research into nuclear power, actions the U.S. and Europe see as potential precursors to a weapons program.

Reports on Friday in Europe suggested Iran is taking steps to shield currency reserves from possible economic sanctions. A curtailment of Iranian petroleum exports would have serious consequences for worldwide crude supplies.

In Nigeria, hundreds of thousands of barrels of daily production has been lost this week after a series of rebel attacks on oil infrastructure.

Natural gas prices, which have fallen all year amid unusually warm weather, were staging a rebound in crude's wake. Natural gas futures rose 38 cents to $9.35 per million British thermal units.

Among energy stocks, oil services shares were rallying after

Schlumberger

(SLB) - Get Report

reported a strong fourth quarter and raised revenue guidance for 2006. Schlumberger shares were up 6% to $121.73 while

Halliburton

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jumped 5.3% to $75.58.

Other shares were mixed, with

Exxon Mobil

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falling 1.6% to $60.51,

BP

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falling 0.2% to $70.11,

Valero

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rising 0.3% to $60.41 and

Chevron

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up 0.7% to $61.18.