Emails obtained by the portal VICE News would indicate that Britain’s only hydraulically fractured shale well – at the Preese Hall site in Lancashire – has suffered a previously unreported structural failure.
The owner of the well, Cuadrilla Resources, denied that the series of emails between the Health and Safety Executive (HSE) — the public body responsible for monitoring well integrity — and the company, dated April 2014, indicate a loss of wellbore integrity. Independent observers, however, have no doubt that well integrity has been breached.
Anthony Ingraffea, Professor of Engineering and Emeritus and Weiss Presidential Teaching Fellow at Cornell University, told VICE News: “It is quite apparent from the language used in [emails between HSE and Cuadrilla] that there was indeed a loss of wellbore integrity followed by attempts to remediate.”
He added that “each integrity failure is a special case in terms of environmental impact, because there are so many factors to consider.”
A spokesperson for the Health and Safety Executive told VICE News: “Some may interpret increased pressure in the annulus as a well integrity issue. The pressure increase in the annulus was well within the design parameters and does not constitute a risk to the health and safety of people; therefore it was not reportable to HSE.
“There was no leak of fluids from the well and the issue has been resolved during the abandonment process. HSE inspectors will continue to monitor the situation.”
Meanwhile Cuadrilla Resources was adamant that “the well integrity at Preese Hall is secure and always has been since the well was drilled and hydraulically fractured in 2011.
“The Health & Safety Executive is fully appraised of all the operations at Preese Hall and has inspected the site and has confirmed on several occasions that there has been no failure of well integrity at Preese Hall.”
This has been confirmed by the spokesperson for the Environment Agency who said: “There has been no unplanned release of fluids from the Preese Hall well, no evidence to date that the gas has escaped into the environment with the gas isolated within the annulus by the well head structure. Groundwater monitoring is still in place on the site.”
The Preese Hall well was abandoned in December 2013 following earthquakes which – scientists believe – may have been caused by hydraulic fracturing operations on the sit.
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