Oil and Gas at Your Door? (2005 Edition) - Earthworks

NON CONVENTIONAL OIL AND GAS
COALBED METHANE—ISSUES AND IMPACTS
Produced Water
Produced water quality varies depending primarily upon the geology of the coal formation.
Typically, saltier water is produced from deeper coal formations. Produced water may contain
nitrate, nitrite, chlorides, other salts, benzene, toluene, ethylbenzene, other minerals, metals
and high levels of total dissolved solids. 170
Depending on which state you live in, produced water may be: discharged onto land, spread
onto roads, discharged into evaporation/percolation pits, reinjected into aquifers, discharged
into existing water courses (with the proper permit), or disposed of in commercial facilities. In
some states, standards for produced water disposal are becoming more rigorous, and certain
disposal practices are losing favor. Surface discharge, for example, is a controversial method of
disposal, as it can lead to a build-up of salts and other substances in the soil, and affect the
productivity of the land. In some states, re-injection is the only option for disposal. 171 See section
on Impacts Associated with Oil and Gas Operations for more information on produced water
disposal options.
In some areas, coal beds may be important local or regional aquifers (natural underground
water storage zones), and important sources for drinking water. 172 It is important, therefore, that
landowners find out how companies are planning on disposing of produced water, and what
impact its removal and disposal might have on water supplies.
Water Quality and Methane/Hydrogen Sulfide Migration
A study conducted by the US Environmental Protection Agency (EPA) documents a number of
examples of water quality impacts and other issues encountered after CBM extraction
occurred. 173 These include reported incidents of:
• Explosive levels of hydrogen sulfide and methane under buildings and inside homes
• Death of vegetation (possibly due to seepage of methane and decreased air in root zones)
• Increased concentrations of methane and hydrogen sulfide in domestic water wells
• Cloudy well water with increased sediment concentrations following hydraulic fracturing
• Strong odors and black coal fines in water wells
• Brown, slimy well water that smelled like petroleum
• Decrease in well water levels and surface water flows following hydraulic fracturing
• The discharge of produced water creating new ponds and swamps that were not naturally
occurring in particular regions
A decline in water quality may be created by hydraulic fracturing fluids. The EPA has stated that
“if coalbeds are located within underground sources of drinking water (USDW), then any
fracturing fluids injected into coalbeds have the potential to contaminate the USDW…
Stimulation fluids in coal penetrate from 50 to 100 feet away from the fracture and into the
surrounding formation. In these and other cases, when stimulation ceases and production
resumes, these chemicals may not be completely recovered and pumped back to the
coalbed methane well, and, if mobile, may be available to migrate through an aquifer.” 174
Water Quantity
Rural residents across the country have experienced decreases in the levels of their drinking
water wells, as well as the drying up of springs. 175 Monitoring wells maintained by the federal
Bureau of Land Management in the Powder River Basin of Wyoming/Montana have indicated
a drop in the aquifer of more than 200 feet. 176 Estimates are that the water levels could drop to
a total of 600-800 feet over the course of CBM development in that basin. 177 I-35