Gas found bubbling up in Divide Creek
Residents of Dry Hollow south of Silt believe that natural gas bubbling to the surface of Divide Creek was freed by gas well drilling operations nearby.But EnCana Oil & Gas (USA) Inc., the company that owns most of the gas wells in the vicinity, is not in a hurry to admit responsibility for the new gas seep.We are very concerned about this issue, said Walter Lowry, director of community and industry relations for EnCana, and we want to do everything we can to identify the source. We have no reason to think right now that this seep is related to our activity.Brian Macke, deputy director of the Colorado Oil and Gas Conservation Commission (COGCC), said his agency is working as fast as possible to find the source of the Divide Creek gas seep, in concert with industry, residents and Garfield County government.The gas was first noticed bubbling from the bottom of the stream by landowner Steve Thompson March 30. For the last 23 years, Ive been coming down here in the spring, and Ive never seen anything like this before, Thompson said.Jaime Adkins of the Colorado Oil and Gas Conservation Commission office in Parachute and Doug Dennison, Garfield County oil and gas auditor, visited the site April 1 and 2, and both said they believe the gas is natural gas.Thompson also notified his neighbors, Lisa Bracken and her parents, Bob and Shorty Eicher, on April 1. The Eicher family owns 60 acres along the creek, downstream from Thompsons 90 acres, and manage their place as a wildlife sanctuary.Divide Creek flows through a broad, partially wooded canyon about 400 feet deep on Thompsons property. A gas drilling derrick stands above and to the southeast of the gas seep, very near to the rim of the canyon. That well and several others nearby are owned by EnCana, a Denver-based corporation that is a branch of a worldwide oil and gas production company.On Thompsons property, Divide Creek sweeps though a wide, gentle ess-curve on the canyon floor. In the middle of the ess, the creek widens and flows among water-rounded rocks.As the creek splits around a small island, its right branch is disturbed by hundreds of bubbles coming to the surface. The bubbles, one-half to three-quarters inch in diameter, float downstream 10 to 15 feet before bursting.Those bubbles arent anything like the bubbles that form in rapids, Bracken said. They are individual bubbles, not the rafts of foam formed by whitewater. And they can be seen rising in strings from the bottom of the creek.
On the streams right bank is a spring, where water rises through the soil and grass. Some of the wet stream bank is discolored with black algae. Spring water wells up in the footprints of elk and deer that frequent the area and flows into the creek.Bubbles rise and burst in the water standing in those footprints and among the sparse grass stalks on the wet bank. A bubbling and fizzing sound is easily heard above the sound of the creek and the calls of red-winged blackbirds.The gas released by these bubbles is flammable. A lighted match held over the bubbles and stream bank vents yields a flame six to 10 inches high, Bracken said.At a few points on the bank, where spring water forms small pools, an iridescent film coats the water. The source has not yet been determined. Bracken said she believes it is a petroleum-based chemical slick, while COGCC officials say it is a thin layer of algal scum.Macke said certain types of algae form slicks like this, and they can be identified easily in the field.Our folks are trained to determine the difference between an algae sheen and an oil slick, Macke said. He said Bob Chesson, an environmental specialist for COGCC, identified the sheen as an algal growth by the fact that it divides easily when disturbed with a stick, while an oil slick holds together.
Divide Creek water downstream from the bubbling gas was collected April 5 and tested by an environmental specialist for the Colorado Oil and Gas Conservation Commission (COGCC). Dennison said the water test results indicate the creek water contains 99 micrograms of benzene per liter of water (mg/l). The amount of benzene considered safe in surface water used as a public drinking water supply is 1.2 mg/l, according to the Water Quality Control Division of the Colorado Department of Public Health and Environment.This level of benzene indicates a serious problem, said Sarah Johnson, assessment unit manager for the Water Quality Division. Benzene is known to cause cancer, Johnson said.The tests also showed that the water contains 100 mg/l of toluene and 17 mg/l of methyl phenol xylene. These amounts are well below levels considered dangerous for those chemicals, Johnson said.This analysis was important, Dennison said, because it gives us an idea its not just swamp gas. Its related to a petroleum hydrocarbon type of deposit.Swamp gas, a product of decaying vegetation, is methane. Natural gas, Dennison continued, is also methane, but natural gas contains other substances that condense out during the production process, such as benzene, toluene and xylene.EnCanas Lowry confirmed that these substances are found in natural gas.
Lowry said both COGCC and a representative of Cordilleran Compliance Services, an environmental consultant hired by EnCana, sampled the gas bubbling from the seep. Technicians for the COGCC and Cordilleran will analyze the samples for their chemical content to determine whether its the same as gas sampled from nearby gas wells. Those results arent available yet.It will take more time to type-match whats in the stream with naturally occurring gas or produced gas in the area, Lowry said.At the urging of COGCC, EnCana has stopped work on nearby wells until the gas bubbling up in Divide Creek can be more thoroughly investigated.The company has already tested its pipelines in the area for leaks, and determined that no leaks exist. This testing is done, Lowry said, by checking for pressure differences, and by walking along pipeline routes with a gas sniffing device.
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Thompson, Bracken and the Eichers, however, believe the gas was released into Divide Creek during the fracturing process that EnCana and other gas drillers use to release natural gas from underground rock formations.Fracturing is done after a well hole is drilled, Lowry said, to release natural gas from rock formations more dense than concrete. In the Divide Creek area, EnCana is producing gas from a sandstone layer called the Williams Fork Formation, which lies about 6,500 or 7,000 feet below the surface.After a steel casing is inserted into the well bore, a pump truck on the surface forces water through openings made in the casing. The water is injected slowly, under such pressure that it fractures the sandstone. Sand mixed with the water prevents the fracture from closing once the pressure is released.Lowry said company technicians control the fracturing process to limit fractures to about 300 feet high and 1,200 feet long. Above the Williams Fork layer, he said, is a shale layer that prevents the fracture from extending upward.The Eicher family disagrees with EnCana on other issues, too, right down to how far the nearest well is from the Divide Creek gas seep. Bob Eicher said he believes it is about 1,200 feet away, but Lowry told the Post Independent he believes the companys closest well is between 2,500 and 3,000 feet away.Bracken said some of the animals that normally frequent the area, especially beavers and frogs, have not been around since the gas started bubbling up in the creek. She has concerns for human residents of the area, too.
There are domestic water wells around here that people have to be concerned about, Bracken said. Macke said Debbie Baldwin, supervising environmental protection specialist for COGCC, took water-well samples in the area and took additional samples from Divide Creek Thursday.Lowry said his company began calling all the residents in the area Wednesday evening, offering to provide drinking water to each household until the test results are received, probably within 48 to 72 hours.At this point, we think the physics of this makes it unlikely that our operations have caused the problem, Lowry said. But were committed to be a good neighbor, because we think its the right thing to do.Macke said COGCC would make certain that, if EnCana is the cause of the seep, the company will be held responsible.If it were found to be coming from one of the wells, Macke said, we would require the operator to take whatever measures are necessary to remedy the situation. As a regulatory body, we have the power to do so. COGCCs mission, Macke said, is to promote responsible oil and gas development and to protect the rights of mineral rights owners, but also to protect the public health, safety and environment.Contact Jeremy Heiman: 945-8515, ext. firstname.lastname@example.org
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