Jim Cramer: Here's what will move oil prices

Geopolitics to rein in bulls? Watch oil prices: Pro
Geopolitics to rein in bulls? Watch oil prices: Pro

Though crude fell Wednesday, with Brent flirting with its lowest level in more than a year, disruption risks posed by mounting geopolitical tensions will dictate the future price of oil, CNBC's Jim Cramer said Wednesday.

U.S. and European Union sanctions on Russia, as well as the ongoing unrest in Iraq, in particular, will have the most influence on oil prices, Cramer said on "Squawk on the Street."

"We've been trying to figure out how to quantify Russia, OK? And what is happening with Russia," Cramer said. "And the way you're going to have to quantify it is that Schlumberger cut numbers ahead of everyone."

The world's No. 1 oilfield services provider on Tuesday became the first major U.S. company to say that its quarterly earnings would be hurt by Russian sanctions. Cramer thinks rival Weatherford International, which gets about 3.5 percent of its revenue from Russia, could be next.

Read MoreRussia retaliates with sanctions: Winners and losers

Weatherford also does a lot of business in Iraq, which remains in turmoil. The Sunni jihadist Islamic State continues to battle Kurdish forces and the Yazidi minority in northern Iraq. In response, the U.S. has launched airstrikes against the ISIS militants.

US conducts additional airstrikes in Iraq: Report
US conducts additional airstrikes in Iraq: Report

"If they don't stop ISIS, you are going to have a big departure in the oil pits," Cramer said. "Hasn't yet happened, but I know that the Iranians and the United States apparently are conspiring to get rid of this guy Maliki."

On Wednesday, Nouri al-Maliki stuck to his guns and refused to accept his removal as Iraq's prime minister.

Still, any of these conflicts could stifle oil production, Cramer said. In turn, he thinks the Market Vectors Oil Services exchange-traded fund could face further declines.

Read MoreOil hit by soaring US inventories

"If you cut drilling in Iraq and you cut drilling in Russia, you're going to cut drilling numbers," he said. "People have to understand, oil service is the first area that's really been hit, and what I so worry about is a worldwide slowdown out of Russia and Ukraine."

—By CNBC's Drew Sandholm. Reuters contributed to this report.

DISCLOSURE: When this story was published, Cramer's charitable trust did not own the Market Vectors Oil Services exchange-traded fund, Schlumberger or Weatherford International.