What lies beneath
y CANDY MOULTON
Star-Tribune correspondent
Sunday, April 22, 2007 2:05 AM MDT
BAGGS -- What began as a small gas seep nearly a year ago has morphed into several larger ground disturbances in two different areas of the eastern Red Desert.
These odd-looking features along Wild Cow Creek near the confluence of Deep Gulch and Cow Creek are methane springs, with hot water and gas spurting from underneath the earth, according to the Wyoming Department of Environmental Quality.
The "mud pots" have appeared as the nearby Atlantic Rim area is being developed for coal-bed methane production by Double Eagle Petroleum Company and Anadarko Petroleum.
They are similar in appearance to mud pots that have appeared in Yellowstone National Park, and their presence has surprised long-time residents of the area.
Savery rancher Pat O’Toole described one of the features as 30 feet wide with gas and water spurting a foot high. When standing nearby if you “just ... close your eyes and listen, it’s graphic,” O’Toole said.
“These things are rolling and boiling,” Little Snake River Conservation District Supervisor Larry Hicks said.
Geology of the area is complex, most agree, but as Hicks noted, “The only thing that we know that has changed in recent history, is the removal of water off the coal seams.”
“I went to one [methane spring] early, maybe three months ago, and there was one there, and now there are four,” O’Toole said. “It is an increasing phenomenon.” His ranching operation takes him through the area at least twice a year as he trails sheep to different grazing lands. “It’s a dead zone, and there’s no tracks,” he added.
Since last June’s first identification of the features in the Deep Gulch area by ranchers and the conservation district, U.S. Bureau of Land Management range managers also have identified additional, similar features along Wild Cow Creek, Hicks said.
According to the state, they appear to be the result of gas bubbling up to the surface.
Both areas are located approximately 12 miles south and east of the outpost of Dad and Wyoming Highway 789, about 25 miles northeast of Baggs.
The DEQ, Wyoming Oil and Gas Conservation Commission, Bureau of Land Management, Wyoming State Geological Survey and Anadarko Petroleum Company have met several times to establish a scientific and engineering understanding of the methane springs in the area.
“After reviewing the data, the source for the bubbling methane springs is from gas and not from water,” said Glenn Breed, geologist and project manager for DEQ. “The strongest evidence is that very little water is associated with the springs. The bubbling effect is caused by gas, which is most likely sourced from coal beds and/or from old abandoned gas wells.”
“The coal-bed methane gas found in the Almond Formation of the Mesa Verde Group along the Atlantic Rim is a natural occurrence,” said Fred McLaughlin, geologist at the Wyoming State Geological Survey, in a release from DEQ.
According to McLaughlin, water pressure forces methane molecules onto coal surfaces. The shift of the methane or release of gas from within the aquifer can result from either de-watering of the coal seam or displacement by another gas.
In the Atlantic Rim area, it appears that the methane springs originated from the release of gas from shallow coal seams, most likely due to fluctuations in aquifer water levels, McLaughlin said.
The relatively recent appearance of the mud pots seems to coincide with the inception of coal bed methane drilling activity. Double Eagle was permitted by BLM to drill 200 wells for CBM as part of an “exploratory” project in the Atlantic Rim area. Anadarko has been drilling CBM wells, and re-injecting produced water from those wells, on private land in the same area.
The 200-well Anadarko drilling project includes the re-injection of produced water associated with the CBM development into a geologic strata located below the coal seam that is being produced. BLM is currently reviewing a proposal fur further extensive development in the area. The Atlantic Rim Environmental Impact Statement notes that if full development is approved there could be another 2,000 CBM wells drilled in the area.
A Record of Decision on that project is expected soon from BLM, but the increasing, unexplained presence of the mud pots has O’Toole, Hicks, and the Wyoming Outdoor Council urging the agency to take another look at potential impacts.
Whether there is a cause and effect relationship between the re-injection of the CBM produced water and the appearance of these mud pots is not yet known, officials have said.
“The appearance of these mud pots is not a reason to reject the idea of re-injection of CBM produced water as a legitimate water disposal method for CBM drilling activities,” said Steve Jones, watershed protection program director for the Wyoming Outdoor Council. “But it may very well point to the need for careful analysis prior to authorizing such re-injection, so that it is well known whether the geologic strata or aquifer into which the re-injection is occurring has the capacity to hold the volume of re-injected fluid contemplated by the proposed project,” Jones said.
“We think BLM ought to be thinking very carefully about approving this [expanded CBM] project and taking another look at it,” Jones said.
In light of this new evidence, Steve Jones added, “The BLM should be investigating whether approving another 2,000 of the same type of wells, into the same geologic strata, will cause more and more mud pots to appear on the Red Desert landscape.”
Also, the methane springs may be evidence that there is a “waste of the resource if it is methane gas that is escaping and is not being captured by the wells that are drilled,” Jones said.
O’Toole urged the BLM to better engage in basin-wide planning and analysis when permitting projects. |
