Rosneft, Gazprom and Lukoil: How big are Russia's oil majors in Singapore?

SINGAPORE is Asia's largest oil trading hub, so it is no surprise that Russian energy giants Rosneft, Gazprom and Lukoil all have a presence here.

Oanda senior market analyst Jeffrey Halley said the Singapore offices are likely to face challenges doing business.

"(This is) not because there is no demand for their products," Halley said. Rather, counterparties will face challenges financing purchases "either through sanctions or fear of breaking sanctions," he said.