Canadian geologist David Hughes is bucking conventional wisdom that natural gas production out of North America's shale formations will continue to increase for a decade or two and sell at a cheap price.

"I'm a bull on gas prices," Hughes told ClimateWire.

Without a massive investment by oil and gas companies in new wells, he said, production out of shale fields in Texas, Louisiana, Arkansas and Pennsylvania will decline. Over time, profit-driven energy giants such as Exxon Mobil Corp., Chevron Corp. and ConocoPhillips Co. aren't likely to invest more in producing cheap natural gas instead of oil.

Less production and higher demand will drive up prices, Hughes predicts, and put the kibosh on a "bridge fuel" that electric utilities and some policymakers hope will replace huge amounts of coal until zero-emissions resources are developed.

"If you look at the Pickens plan, and if you look at the gas lobby, they're suggesting that natural gas production can grow so much that we can replace a substantial amount of coal for electricity and oil for transport," Hughes said.

"They're not taking into consideration the number of wells it will take to do that, and the price of gas it will take to do that."

Hughes joins a small handful of contrarians questioning whether U.S. shale fields will yield a bounty of cheap natural gas for the next 20 or 30 years. His position isn't too far off from that of the so-called "peak oilers" who express skepticism about the bounty of oil in the world. When it comes to natural gas, there are skeptical geologists who feel gas is far more constrained than producers admit.

Meanwhile, the U.S. Energy Information Administration and the Potential Gas Committee out of the Colorado School of Mines stand by figures suggesting gas supplies are on a rising trajectory that could keep prices in check.

Congress has been reluctant to give too much of a lift to gas through federal incentives, in part because of concern about volatile prices. But the plan put forth by Texas oil magnate T. Boone Pickens to convert the trucking fleet to natural gas has some significant footholds in Congress. The "NAT Gas Act," sponsored by a House Democrat, and a proposal supported by the Senate Democrats could be folded into pending energy bills and garner bipartisan support.

The questioning contrarian warns of a 'pipe dream'

From this geologist's perspective, it could be a big mistake. In a paper written for the Post Carbon Institute, based in Santa Rosa, Calif., Hughes said historical data, technological limits, geological realities and economic interests suggest gas boosters are over-exuberant.

"Shale gas is characterized by high-cost, rapidly depleting wells that require high energy and water inputs," the report says.

Energy analysts and boosters of using more gas to replace coal say advancement in the production process of horizontal drilling and hydraulic fracturing vastly expands access to previously inaccessible gas. Nearly half of U.S. gas production will eventually come from onshore shale fields, they predict, and replace declining production in the Gulf of Mexico and Canadian imports. Further, a growing amount of that shale gas is expected to go toward slashing carbon dioxide emissions and toxic smokestack pollution.

To produce that gas, Hughes says, the commodity price will have to be significantly higher than $4 per million British thermal units. That's where the price has hovered for about two years.

"Other analyses place the marginal cost of shale gas production well above current gas prices," Hughes said in the report, "and above the EIA's price assumptions for most of the next quarter center."

Production out of wells in the largest shale formations, the Haynesville in Louisiana and Barnett in Texas, declines rapidly. That has shrunk the potential productivity of those fields, Hughes said, and gas companies will have to drill more wells from one year to the next to maintain production levels.

Even if government analysts are correct in predicting significant production growth, says the paper, production would have to increase by more than 60 percent to replace a large amount of coal and gasoline.

"This would also require a massive build out of new infrastructure, including pipelines, gas storage and refueling facilities," Hughes said in the paper. "This is a logistical, geological, environmental and financial pipe dream."