HMM: OPEC, have no fear: The U.S. oil-shale output crash is here.

The energy industry is already suffering from the impact of spending cuts over the past several years, said Phil Flynn, senior market analyst at Price Futures Group, in a webinar held Tuesday afternoon.

“We’re losing investment in the energy industry,” he said. “It’s taking its toll.”

Global energy exploration and production capital expenditures are expected to fall by 22%, or $740 billion, between 2015 and 2020, he said, citing a report from Wood Mackenzie issued last year. Including cuts to conventional exploration investment, Wood Mackenzie said that figure increases to just over $1 trillion.

Discovery of new oil fields has already “plunged” to its lowest level since 1947, as exploration companies cut back in the wake of the drop in oil prices, Flynn said. Year to date, West Texas Intermediate crude CLQ7, +1.27% and Brent crude LCOQ7, +1.18% prices have dropped by roughly 18%.

Shale-oil production is climbing, but that growth is slowing down, said Flynn. He pointed out that while the number of U.S. rigs drilling for oil has grown for 23 weeks in a row, based on Baker Hughes BHI, +0.24% data, new-well oil production per rig among the shale plays has slowed.

A crash in shale-oil production is “starting now,” Flynn told MarketWatch in an email. “It will become more clear in a few months.”

Shale oil production rebounded very quickly after the last crash, and drove prices right back down. Is there some reason that can’t or wouldn’t happen again?