Russia's energy minister canceled his appearance this week before a major global energy conference in Houston, where the Russian invasion of Crimea has now become a part of the agenda.
Oil and gas prices jumped Sunday night, as traders assessed the impact of geopolitical tensions between Russia, Western Europe and the U.S.
Alexander Novak, Russia's energy minister, was slated to speak Tuesday as part of a panel at the annual IHS CERAWeek conference, but pulled out on Saturday, the day after Russian troops moved into Crimea. The conference has now added a panel of speakers who are experts on Russia and Ukraine.
"Depending on how this plays out in the next week or two, it will have a big impact on energy security," said IHS Vice Chairman Daniel Yergin. "Russia will want to maintain its reputation as a credible supplier."
(Read more: G7 condemns Russia's move on Ukraine, halts G8 prep)
Russian troops entered Crimea Friday, seizing control of the peninsula. Crimea, part of Ukraine since 1954, has a large Russian population and is a vital base for the Russian Navy's Black Sea fleet.
"It's very hard to see the end game," said Yergin. He said the situation has not only raised questions about energy supply for Europe, but it raises questions about Syria and Iran, where Russian cooperation is needed.
The situation in Ukraine has spun out of control quickly, with the ousting of President Viktor Yanukovych a week ago. President Barack Obama said there would be "costs" for any military intervention. German Chancellor Angela Merkel and British Prime Minister David Cameron both called Putin, seeking de-escalation.
U.S. Secretary of State John Kerry said there could be economic sanctions placed on Russia. Kerry will meet with senior representatives of Ukraine's new government Tuesday in Kiev.
(Read more: Global tensions over Ukraine 'highest since 9/11')
The G-7 Sunday condemned the Russian action and said the G-8 was canceling preparations for a summit that had been scheduled to take place in Russia in June.
Andrew Lipow, president of Lipow Oil Associates, says Russia and the European Union are "entwined and need each other," with the EU the biggest market for Russian energy exports.
Of the 16.8 billion cubic feet of gas consumed by the EU annually, about 30 percent is imported from Russia, he said. Russia exports about 3.5 million barrels per day of oil to the EU, which uses a total 11.5 million barrels per day.
While Ukraine is not a strategic energy producer, it is strategic for the pipelines that cross it, filled with Russian gas enroute to Europe.
"Russia has had a standing policy for a decade of reducing dependence on pipelines to Ukraine," Yergin said, adding a new gas pipeline, Nord Stream, goes through the Baltic to Germany.
Yergin described Novak as a reformer, saying he understands the problems of Russia's energy industry and was working to modernize it
—By CNBC's Patti Domm. Follow her on Twitter @pattidomm.