Water Well "Problems" in Areas of Unconventional Resource Developments: Appearances are Deceiving and Solutions are Many
Fontana, John V.; Seneshen, David
VistaGeoScience, Golden, CO.
Public concern is growing about water well-related issues such as quality and productivity in areas of unconventional oil and gas development and, more generally, about the potential future risk to regional aquifer systems. When development occurs in populated areas, operators and regulators are frequently notified of complaints from water well owners suspecting that their water well is being damaged from nearby development. The geology in the areas of unconventional resource developments, such as shales, tight sands and gas-saturated coals, is more likely to affect water quality in fresh water aquifers than in other regions. This is also the case with shallow uranium deposits. Hydrogeologists generally believe the increasing public hysteria about drilling and hydrofracturing practices damaging water supplies is unwarranted and what is coming to light is the existence of this naturally occurring "contamination" and other common water well problems.
Anthropogenic contamination releases do, however, occur and must be acknowledged, remediated, and prevented. However, water wells can become non-productive or their water quality degraded due to regional over-use of the aquifer, drought, bacterial or mineral well fouling, or the naturally limited life span of the well. Methane in a water well occurs naturally from bacteria, natural gas seeps, or the result of shales or coals present in some aquifers. Since methane occurs naturally and is not toxic, it is excluded from routine water quality tests of private wells. Some regulatory agencies require that nearby water wells are tested for methane and other constituents before oil & gas wells are drilled. This testing can reveal the presence of pre-existing anomalous methane concentrations or other issues.
Fears about drilling and hydraulic fracturing are rapidly spreading as unconventional resources increasingly become targets for development. Many states in the USA have, or are now proposing, regulations to require baseline water testing and monitoring to address these concerns. In response, some industry associations are working closely with regulators to develop programs based on best practices. Such cooperative interaction could be a highly effective model to mitigate water-related concerns associated with global development of unconventional resources.
Uranium roll front deposits, another energy mineral, commonly form in shallow freshwater aquifers where dissolved oxidized uranium migrating with ground water flow encounters a naturally reduced environment, and the uranium and associated metals (e.g. vanadium, molybdenum, etc) precipitate out forming the deposit. Where this is happens the ground water will contain high concentrations of dissolved uranium, radium, and radon gas. These same aquifers can be a ground water source for homeowners, farmers and ranchers. Routine water quality tests of domestic wells do not include these compounds, so they will likely not be discovered until a company develops the resource.
Prior to unconventional resource development, a proactive baseline testing program can head-off these problems with stakeholders. If, however, such testing is not done prior to development, forensic geochemical methods can typically distinguish the source as natural or anthropogenic, unless it's a natural seep from the same source as the developed resource.
Methods are presented to assist resource developers in the documentation of pre-existing environmental conditions and location of potential problem areas that can allow them to effectively address complaints. Procedures are outlined that will help operators protect themselves from potential legal action by regulators or civil law suits. These procedures include educating water well owners about common water well problems such as natural methane, natural or anthropogenic contamination, and proper well maintenance.
AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012