Oil price indices were mixed early in the Thursday session as traders tried to make sense of the bond-buying initiative from the European Central Bank.

Beginning in March, the ECB said it would purchase bonds valued at more than $65 billion per month through September 2016 as part of a so-called quantitative easing program meant to stimulate the struggling European economy.

ECB President Mario Draghi said low inflation and the secondary effects of low crude oil prices meant it was time to act to save the ailing eurozone from further calamity.

"Thus, today the adoption of further balance sheet measures has become warranted to achieve our price stability objective," he said in a statement.

Inflation in an already struggling eurozone turned negative in December, driven in large part by falling energy prices.

Marc Ostwald, a strategist at ADM Investor Services, told the Wall Street Journal the nuances of the ECB's action were yet to be vetted.

"It's almost as though they have made this so complicated that markets cannot react," he said.

Former U.S. Treasury Secretary Larry Summers said from the sidelines of the World Economic Forum in Davos, Switzerland, the ECB actions likely won't right the European economic ship.

"We're all for quantitative easing in Europe, but it's not enough," he said.

Key crude oil indices were mixed early in the Thursday session. The price for Brent, the global index, was up less than half a percent to just under the $50 per barrel mark. The price for West Texas Intermediate, the U.S. benchmark, lost 0.4 percent from the previous close to trade near $47.60 for March delivery.

The International Monetary Fund said this week that, while low oil prices are a net benefit for consumers, the gains were offset by adverse factors elsewhere in the global economy.