Organisation of Petroleum Exporting Countries (OPEC) has expressed optimism that slash in global investment by $130 billion in 2015 from its level of $650 billion in 2014 would lead to increase in crude oil prices.

The projection was based on the fact that investment in new or expansion projects has plummeted, supply will tighten and as supply falls, prices inevitably rise.

The Secretary General of OPEC, Abdalla Salem el-Badri. El-Badri’s said in a speech at the oil and money conference in London yesterday that global investment could drop by $130 billion in 2015 from its level of $650 billion in 2014.

Oil industry leaders have dismissed talk of the price of crude hitting the $20 lows predicted by analysts, who warned that believing that “oil prices will be with us forever may not be the right way of thinking.”

Goldman Sachs stirred energy investors last month when its head of commodity research warned of rising risks of oil prices falling as low as $20 per barrel.

The Executive Director of the International Energy Agency (IEA), Fatih Birol, told CNBC Tuesday low prices will prompt U.S. producers to cut output, creating upward price pressure.

“When we look at the next few quarters, we expect U.S. oil production to decline because of low oil prices and in Iraq, production growth will be much slower than in the past. And the demand is creeping up,” Birol told CNBC Tuesday from the annual oil and money conference in London.

 “So therefore, to think that oil prices will be with us forever may not be the right way of thinking.”

The U.S.-led revolution in the extraction of shale gas via hydraulic fracturing or “fracking” has pushed more oil into the market. At the same time, the OPEC group of oil-producing countries have stood firm in the face of international pressure to cut prices. Meanwhile, Iraq has increased production, while demand growth for energy has slowed, largely due to the deacceleration in the Chinese economy.

This has helped catalyse an historic collapse in the price of crude oil, with both Brent and WTI trading below $50 per barrel, down from around $110 per barrel until June 2014.

Whether or not U.S. shale players will cut production in response to ongoing low prices is a moot point however. They could instead respond by increasing production in order to satisfy creditors eager for results. Plus, against some odds, shale producers have managed to lower productions costs, although these remain high in comparison to conventional oil production.