A lesson was perhaps reinforced for ExxonMobil (NYSE: XOM) this week: The legal system giveth, and the legal system taketh away.

On Tuesday, a U.K. judge removed an order freezing $12 billion in assets of Petroleos de Venezuela SA -- PDVSA -- the national oil company of Venezuela. Those assets had been frozen at Exxon's request, pending international arbitration relating to Venezuela's (read: Hugo Chavez's) nationalization of ExxonMobil's Cerro Negro heavy oil project in the nation's Orinoco basin.

Chavez also expropriated assets from Chevron (NYSE: CVX), ConocoPhillips (NYSE: COP), BP (NYSE: BP), France's Total (NYSE: TOT), and Norway's Statoil (NYSE: STO). Four of the companies accepted Venezuela's settlement terms, while Conoco is still negotiating with the Chavez regime. Exxon has pursued international arbitration, a path that could consume three years.

But the beat clearly goes on. Orders remain in place in the Netherlands and New York to seize Venezuelan assets, although it is impossible to predict how long this those orders will persist. At the same time, PDVSA apparently has ceased shipping crude oil to a Chalmette, La., refinery that it owns jointly with Exxon. Instead, according to Venezuelan Oil Minister Rafael Ramirez, the oil that would have gone to Chalmette is being diverted to China.  However, there are reports that Exxon has refused to accept oil shipped from PDVSA to Chalmette.

In releasing his decision, the U.K. judge, who indicated that he agreed with PDVSA's contention that the Venezuelan national company has no ties to England, did not specify the reasons behind his finding. Those reasons are expected to be made public later this week.

In the meantime, Venezuela clearly constitutes a prime example of the difficulties that the major energy companies all too frequently encounter as they attempt to find and produce oil and gas worldwide. In addition to Venezuela, Big Oil has faced difficult situations during just the past year in Russia, Nigeria, and Kazakhstan.

I feel that ExxonMobil's demonstrated ability -- and willingness -- to go toe-to-toe with frequently obstreperous governments in places where large amounts of oil happen to have been deposited is ample reason for Foolish investors to keep at least one eye cocked on the company. That recommendation will only strengthen when, as I believe is inevitable, the world's thirst for "black gold" materially exceeds its supply.

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