With oil, natural gas and coal prices all running high, state revenue is getting a boost from its fossil fuel extraction industries.

But a slowdown in drilling may indicate that a decade-long natural gas production increase is beginning to plateau, officials say.

As of Friday, there were 66 active rotary rigs in Wyoming, according to Baker Hughes. Wyoming averaged close to 100 rigs in 2005, about 70 in 2007.

Coal-bed methane rigs declined by 16 since March, while rotary rigs declined by seven, according to the Wyoming Department of Revenue's economic analysis division. For the most recent 12-month period compared to the previous twelve months, coal-bed methane rigs declined 12.9 percent while rotary rigs dropped off by 23.9 percent.

"We're trying to find out where that new equilibrium is for rigs," said Jim Robinson, senior economist for the economic analysis division.

Wyoming's natural gas producers increased export volumes an average of 6.4 percent annually for the past 10 years, according to the Wyoming Oil and Gas Conservation Commission. During that time, Wyoming went from the nation's No. 7 natural gas producer to No. 2.

Generally, it takes more and more wells to produce the same amount of gas each year. It's known in the industry as the "decline ratio." So in order to sustain the Rocky Mountain region's 4 percent average annual production increase, the industry must exponentially increase the number of wells it has on the ground today.

Industry officials say they're getting too much push-back from conservationists in places including Colorado, the Pinedale Anticline and the Wyoming Range to maintain the same rate of production growth recorded in recent years.

"As rig counts go down, those rigs move into other states where they can stay active. And getting those rigs back can be difficult," said Bruce Hinchey, president of the Petroleum Association of Wyoming.

Drilling on federal leases in south-central Wyoming is expected to slow to a halt until a federal environmental impact statement is completed in the Bureau of Land Management's Rawlins field office. Industry officials worry the same scenario could play out in the Pinedale Anticline.

Already, coal-bed methane producers experience a drastic slowdown during the winter and springtime due to federal sage grouse and raptor seasonal stipulations.

But environmental concerns are not entirely to blame, Hinchey said.

Last year, natural gas production in the Rockies exceeded pipeline export capacity, which severely depressed wholesale prices for producers here.

State economists worried that if limited pipeline infrastructure continued to hobble prices in the Rockies that gas producers might focus their capital elsewhere. But it has only been a few months since a major pipeline export expansion brought Rockies natural gas prices back in line with the rest of the nation.

"As far as production, once a company -- large or small -- makes that commitment, they are going to stick it out as long as they can," Robinson said. "Large companies can ride out bad prices for six months to a year."

Robinson said he suspects the oil and gas industry is working less overtime. The number of employees in the industry seems to have stabilized at about 18,000, while the number of rigs has declined.

"They're probable working less overtime. That's why we see the number of rigs down and employees maintaining," Robinson said.

Energy reporter Dustin Bleizeffer can be reached at (307) 577-6069 or dustin.bleizeffer@trib.com.