Jul. 5--Natural gas wells could eventually crisscross the rock formations below almost every part of Arlington, but one area is expected to remain off limits.

City Attorney Jay Doegey said that standard language in contracts with the Dallas Cowboys probably would prohibit drilling under the team's new stadium. He said there are concerns -- although they are remote -- that drilling could affect the building's structural integrity.

"We don't want the ground to give and cause it to crack or sink," Doegey said about the rock beneath the stadium.

The language was put in the contracts long before five small earthquakes shook Cleburne in a single week in early June. Researchers are looking into whether those and many others recently were the result of extensive gas drilling in the underground Barnett Shale formation.

Earthquakes have been rare in North Texas until recently. Thousands of wells have been drilled in the western areas of North Texas in recent years.

Arlington and the Cowboys' decision to include the language could potentially make it harder -- but not impossible -- to lease the 200-acre stadium site for drilling. The options are already limited since the property is in a developed area.

Attorney Glenn Sodd, who represented some property owners whose land was acquired for the stadium, said this is the first he's heard of the potential ban. It's of particular interest to him because his last group of clients who settled was allowed to keep some mineral rights through a deal that hadn't been publicized before now.

At stake could be thousands of dollars for Sodd's clients and potentially millions for the city.

By banning drilling under the stadium property, the city could only lease the land to drillers if it were "pooled" with adjacent property. The drilling would have to occur under the other property, but revenue would be split among all mineral rights owners.

There are no immediate plans to lease the stadium land for gas drilling, and the market for such leases has slowed dramatically in the past year. The recession and falling natural gas prices have dropped signing bonuses from nearly $30,000 per acre in some areas to about $2,000 to $2,500 per acre.

Doegey said the city hasn't conducted any research to calculate potential dangers of drilling underneath a megastructure like Cowboys Stadium. But he said there has to be a concern about drilling beneath a structure that expensive ($1.15 billion) and that heavy (more than 805 million pounds).

"I don't know that we would want to take the chance, even if it was a long shot," Doegey said.