A Wyoming unit of the U.S. Bureau of Land Management (BLM) has reversed the environmental assessment (EA) process to consider possible climate change impacts on a proposed 156-well drilling project by Houston-based EOG Resources Inc. in the Powder River Basin (PRB).

An original January determination of "no significant environmental impact"  has been stayed following protests from two environmental groups, Western Watersheds and the Center for Biological Diversity. BLM re-evaluates its EAs when deficiencies are identified, said Wyoming BLM spokesperson Bradford Purdy.

EOG's Sand Creek project calls for horizontally drilling up to 156 oil and gas wells on 26 pads in the northeast part of the state. Purdy said the vast majority of the well pad locations are in areas where the surface is private land, but the subsurface ownership is a mix of private and federal government minerals.

Originally, BLM analyzed two alternatives for the project -- no action and proposed action -- concluding that  it would cause "no significant impact" to the environment. The project was approved to move forward, but that did not include drilling, which has to be handled in a separate permitting process.

Subsequently, BLM's Casper Office requested that the emissions portion of the earlier EA be remanded to the field office so additional analysis could be included, and the state [BLM] office agreed, Purdy said. "The Casper office is currently working on updating the emissions analysis in the EA," he said.

In recent years, EOG has been completing wells all over the lower 48 states, becoming one of the biggest U.S. producers. It has focused on oil targets in the PRB, the Denver-Julesburg Basin, the Permian’s Delaware sub-basin, and the Eagle Ford and Bakken shales.

In the Sand Creek proposal, EOG included a 50,163-acre area in northern Converse County, covering, private, state and federal lands. It proposes to drill up to six wells for each of its pads, targeting more than a half-dozen formations (Dakota, Frontier, Mowry, Muddy, Niobrara, Parkman and Turner) in the PRB.

Last summer, senior executives at EOG affirmed their strong interest in the PRB even as the company continues to be known for its diverse holdings in basins across the country. Last August, EOG went all in on parts of the PRB to exploit the Mowry and Niobrara formations, making the PRB its third-largest asset.

"PRB demonstrates the value of our exploration focus where we have been able to expand our assets in size and quality, adding many new locations much faster," CEO Bill Thomas said on a conference call at the time.