Oil prices at multi-year lows may be just the beginning, with some analysts forecasting "black gold" may permanently lose its luster.
"We have entered a new era in world oil," Dan Yergin, vice chairman at IHS and Pulitzer Prize winning author of The Prize: the Epic Quest for Oil, Money and Power, told CNBC. "The dominant thing is this growth in U.S. supply," he said, noting production there is up 80 percent since 2008 for an output greater than 11 out of 12 OPEC countries.
"That's happened, combined with what the head of the IMF has called the 'new mediocre' in the world economy. Suddenly, this sense is that things are weaker and then out of the blue, this failed state called Libya, which was producing almost no oil, suddenly puts a million barrels of oil into the market," he added.
WTI prices were around $80.85 a barrel in early Asia trade Monday, hovering near lows last seen in 2012, while was trading around $85.73 a barrel, not terribly far from its 2010 lows, according to Reuters data.
Even with WTI prices around $80 a barrel, Yergin doesn't expect U.S. production will slow, although price levels below that might "see a lot of pain" among producers.
"It's unusual that we have this much risk in the world -- Russia, Ukraine, ISIS, North Africa, Nigeria -- and yet the price has gone down. That tells you how powerful - at least right now - supply and demand is," he said.
Others also expect long-term weakness in oil prices.
"We have greater confidence in the scale and sustainability of U.S. shale oil production. This implies that the global cost curve has shifted lower and that cost deflation is sustainable," Goldman Sachs said in a note dated Sunday.
In addition, "accelerating non-OPEC production growth outside North America will outpace demand growth, leaving the global oil market oversupplied," it said.
Goldman cut its WTI crude oil forecast to $75 a barrel for the first quarter and second half of next year, down from $90 previously, and lowered its Brent forecast to $85 a barrel from $100 previously. For the second quarter of 2015, when it expects global oversupply will be at its worst, it expects WTI at $70 a barrel and Brent at $80.
It expects fundamentals will stabilize in 2016, with U.S. production growth likely to slow and OPEC likely to make moderate production cuts, setting a 2016 and long-term forecast at $80 a barrel for WTI and $90 for Brent.
To be sure, IHS's Yergin noted that geopolitical risks could still wield a great deal of power over oil prices.
"If you have some other major political shock that interferes with things, that actually affects supply, things could turn around," Yergin said.
Goldman also sees some risks to its bearish view.
"A collapse in Libyan oil production would offset our expected first quarter of 2015 inventory build forecast, as Saudi and the rest of core-OPEC do not have enough spare capacity to fully absorb this hit," Goldman noted. It also cited some uncertainty about the price level that would be needed to get U.S. shale production growth to slow.
Libya may be facing civil war, with heavy fighting between the army and Islamist militias as two rival governments vie for power three years after long-time ruler Muammar Gaddafi was overthrown.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1