In exchange for winter drilling, Questar has agreed to a number of mitigation measures, which the company maintains go far beyond what is required under current environmental regulations.

Ron Hogan, general manager of Questar Market Resources' Pinedale Division, said year-round drilling provides for a "safer, more continuous drilling activity," which allows the company to develop the mesa's natural gas resource in half the time as it would under previous approvals.

Combined with directional drilling, total surface disturbance by Questar will be reduced from 1,500 acres to 500 acres. In addition, Questar has built a $25 million pipeline system to transport water and condensate off the mesa rather than use trucks, eliminating 25,500 truckloads of liquids per year.

"It allows us to be an environmentally more conscientious company," Hogan said. "Environmental groups backed this. In this particular case, we received written support from Trout Unlimited and from the North American Grouse Partnership. And because there was not a lawsuit filed, I guess by default that's an endorsement by most of the other groups."

However, what was considered a one-time experiment with winter drilling is fast turning into business as usual, according to Linda Baker, community organizer of the Upper Green River Valley Coalition, a grassroots conservation group based in Pinedale.

"Nobody really knows if a through-winter drilling proposal like this, despite its good ideas, will be a fair trade," Baker said. "Will we see a continued drop in population numbers as a result of oil and gas development on crucial winter ranges in the winter? That is the most important question."

And it appears Questar will be followed by other producers who want to implement year-round drilling.

Shell, Ultra Resources and Anschutz have filed a joint application to the BLM for winter drilling. A decision by the BLM is expected this month.

"I'll be the first to tell you we're not doing everything right," said J.R. Justus, Shell's U.S. Onshore Asset Manager. "There are things that we could do better than we're doing now. Pinedale, from Shell's perspective, has been a tremendous learning experience. The Pinedale Anticline is a very complicated field with a lot of issues and a lot of challenges."

If approved, Shell plans to drill 20 wells on a single site pad this winter. Ultra is asking for two drilling rigs on one pad to drill up to 16 wells. And Anschutz is asking to clear an area in preparation for winter drilling.