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Due to a rising number of accidents, spills and leaks, the Department of Energy started to compile and publish open public statistics. During the shale gas rush in Pennsylvania more than 75 companies drilled thousands of wells and fractured rock formations throughout the state in 2007. The failure rates of shale gas wells in heavily fractured jurisdictions with transparent regulation has now become a significant issue. Environmental Protection Agency factually noted that “if fracturing fluids have been injected to a point outside of the well’s capture zone, they will not be recovered through production pumping and, if mobile, may be available to migrate through an aquifer.” Leaking of toxic fracture fluids is also common because only 25 to 60 per cent of diluted chemicals and water used to blast open shale or coal formations are ever recovered. In Alberta the industry remains largely self-regulated. Theresa Watson, now a member of Alberta’s Energy Resources Conservation Board, also disclosed that an increase in the number of water wells in heavily fractured oil and gas fields would increase “the likelihood that gas, due to migration through shallow zones, can accumulate in buildings.”Īlberta’s energy regulator does not yet keep track of leaking wells in a rigorous or transparent fashion but it does note in a 2011 Field Surveillance Report that leaks and methane migration are routine items of “high risk noncompliance” that companies voluntary disclose to the regulator. The many ways methane can escape a natural gas well. Moreover “ high pressure fracturing” increased the potential to create pathways to other wells, the atmosphere and groundwater. But a 2009 study by Alberta scientists Stephan Bachu and Theresa Watson found that so-called “deviated wells” (the same kind right angling used for fracturing shale gas and tight oil formations) typically experienced leakage rates as high as 60 per cent as they age. “I’m 65 and I’ve had a knee replaced.”īased on industry reports to regulators as opposed to independent audits, about five per cent of Alberta’s 300,000 oil and gas wells now leak. “Anything that ages starts to fail,” explains Ingraffea. The Norwegian Petroleum Safety Authority reports that 18 per cent of its deep offshore oil and gas wells have integrity problems, while Australia struggles with chronic leaks from fractured coal bed methane wells. Abandoned wells also can become major pollution portals. Old and decaying cement jobs largely explain why offshore oil wells in the Gulf of Mexico report leakage rates as high as 60 per cent after 16 years of service. Where ever drillers have not properly sealed and cemented wellbores in deep shale rock, the gas will escape and move through rock fractures (existing or industry-made ones) into groundwater, stream beds, water wells and even the basements of houses.Īging can affect leakage too. Methane, by its very lightness, wants to go up. Even a 2003 article in Oil Field Review, a publication of Schlumberger, reported that, “Since the earliest gas wells, uncontrolled migration of hydrocarbons to the surface has challenged the oil and gas industry.” In fact leaking wellbores has been a persistent and chronic problem for decades. But the worst leakers remain “deviated” or horizontal wells commonly used for hydraulic fracturing. As wells age, the percentage of leakers can increase to a startling 30 or 50 per cent. Moreover industry studies clearly show that five to seven per cent of all new oil and gas wells leak. In other words fracture fluid or methane leaks are “a rare phenomenon.”īut industry data disproves this dubious claim says Cornell University engineer Anthony Ingraffea, the main source for this series, who has studied the non-linear science of rock fractures for three decades.

One of the boldest claims made by the shale gas industry goes like this: oil and gas companies have drilled and fractured a million oil and gas wells with nary a problem. When industry says hardly ever, that’s a myth. Shale Gas: How often do fracked wells leak?