Hydraulic fracturing, properly managed and regulated, can be conducted in the UK without threatening groundwater or creating risks of serious earthquakes, according to a joint study by two British research groups.
"Hydraulic fracturing can be managed effectively in the UK as long as operational best practices are implemented and robustly enforced through regulation," concluded a review, funded by the government's Office of Science, by the Royal Academy of Engineering and Royal Society.
The study deemed "very low" the risk that induced fractures would propagate from shales deeper than "many hundreds of meters" to overlying aquifers. More likely causes of contamination, it said, are faulty wells and spills associated with surface operations.
"Neither cause is unique to shale gas," it said. "Both are common to all oil and gas wells and extractive industries."
On earthquakes, the study's findings parallel recent findings by the National Research Council in the US and by a government review in the UK of a study commissioned by Quadrilla Resources Ltd. of seismicity induced by hydraulic fracing in Northwest England (OGJ Online, June 15 and Apr. 17, 2012).
The new study said seismic events caused by fracing are likely to be weaker than those associated with coal mining, which are weaker than natural seismicity.
The study made a number of recommendations, many addressed to regulators and research groups. Recommendations directly addressing or involving operators include:
• Site-specific monitoring of methane and other contaminants in groundwater before, during, and after shale gas operations.
• Development of arrangements for monitoring abandoned wells.
• Well-integrity tests, such as pressure tests and cement bond logs.
• Monitoring of seismicity before, during, and after hydraulic fracturing.
• Sharing of data with government officials to establish a national database of shale stress and fault properties to assist with identification of well locations.
• Monitoring of potential leakage of methane or other emissions to the atmosphere before, during, and after shale gas operations.
• Implementation of methods for minimizing water use.
• Recycling and reuse of wastewater where possible.
• Planning "from the outset" for treating and disposing of wastes.
• Environmental risk assessments.
• Goal-based risk assessment to reduce risk to "as low as reasonably practicable."
• Mechanisms to allow reporting of well failures and other accidents between operators.
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