A new report from researchers at the University of Waterloo in Canada highlights a serious problem for the oil and gas industry – leaking wells.
The steel pipes and cement used to build oil and gas wells sometimes don’t form a complete seal against the rocks into which they’re drilled, which can allow natural gas, brine, or other fluids to leak out. As the researchers note, the potential consequences of poorly built or maintained wells include, “…groundwater quality deterioration, contributions to greenhouse gas emissions and explosion risks if methane gas accumulates in inadequately ventilated areas.”
The researchers identified many different factors that may contribute to leakage problems – everything from the type and quality of well construction materials to lack of accountability and corner-cutting in response to pressure to drill faster and cheaper.
These leak pathways can develop both immediately, if wells are not constructed correctly, and over time as a result of stresses on well construction materials from production activities (e.g. hydraulic fracturing, injecting fluids for enhanced oil recovery, etc.) and as well construction materials degrade. Complicating matters further, it can be difficult and expensive to find and fix the source of leaks.
Leaking wells contaminated groundwater in numerous documented cases, including in Ohio, Colorado, and Pennsylvania. The scale of the problem is poorly understood because of a lack of systematic monitoring and reporting, but some regional studies in Canada documented up to 20% of wells with leakage problems. It’s unclear what percent of those leaking wells could be impacting groundwater or releasing methane into the atmosphere.
The researchers identify long-term well integrity as one of the most significant problems facing the oil and gas industry. NRDC has also repeatedly raised this concern, in blogs, in comment letters to the EPA, the BLM, the state of California, and elsewhere. With millions of existing oil and gas wells in the United States, and tens of thousands more being drilled every year, this is a problem we cannot afford to ignore.