"If we allow for aggressive exploration in the United States and allow natural gas to come in from Alaska and allow (liquefied natural gas) to come in from overseas, we could see what the National Petroleum Council calls a 'balanced future,'" Brown said.

"Those (prices) by today's standards would be quite low prices, but by standards of a few years ago they would be quite strong prices," he said.

Brown had a receptive audience at the IPAA, an upstream trade group. Association chairman John Walker called for a government policy devoted to building home-grown supplies.

The group has long supported opening new drilling areas by eradicating environmental restrictions and other impediments to production offshore, in Alaska and in the lower 48 states, including the Rocky Mountains.

If the development of LNG terminals is blocked, if producers are unable to win access to environmentally sensitive gas fields and if a long-awaited pipeline from Alaska does not materialize, Brown said, prices would be much higher.

"These prices are not good for the U.S. economy and they're not good for the energy industry," Brown said.

Brown predicted a middle ground where some new natural gas comes to market, most likely priced between $5 per million Btu and $6 per million Btu.

"That's consistent with the long-run outlook in the futures market that says we're going to get some things right but we're not going to get everything right," he said.

Shell Exploration & Production's chief executive officer for the Americas, Raoul Restucci, said demand inevitably will outstrip declining domestic production.

"The reality is the treadmill is moving faster and faster and faster," Restucci said. "The only relief valve out there is LNG."

Brown also forecasted that the current energy price pinch will not trigger another domestic economic recession, although it could restrict growth. "Whether it will cause a recession or not, I think the answer is no, but I think it will threaten our economy," he said.