Merger and acquisition activity in the global energy sector rose 23 percent from 2013 despite investment declines, analysis Monday from IHS finds.

Crude oil prices are trading at close to half of their June values, forcing some of the biggest oil and gas companies in the world to reconsider their investment plans for 2015.

Christopher Sheehan, director of merger and acquisition research for the analysis firm, said the steep drop off in crude oil prices in late 2014 nearly brought amalgamations to a halt.

"Buyers and sellers are having difficulty reaching a consensus because of the oil price tumble, which is causing significant uncertainty for the industry," he said in a statement Monday.

Nevertheless, IHS said companies were robust in their merger and acquisition activity last year, to the tune of $173 billion. That's in contrast to the previous year, when energy companies were hording cash to develop newly-acquired reserves.

Globally, the industry saw a 4 percent increase in mergers and acquisitions year-on-year, though North America accounted for around 60 percent of the worldwide activity.

Transactions outside North America fell off the map, however, as competing strains of economic sanctions on producing nations like Russia and low crude oil prices take their toll in the investment climate.

Companies carrying significant debt into 2015 could find themselves the target of takeover bids, especially if oil prices stay low during the first half of the year, Sheehan said.