Fracking safety: report warns of "significant unknowns".

Guardian: “The lack of publicly available data on the UK’s onshore oil and gas drilling means there are significant “unknowns” about the safety of future fracking wells, according to a new study. The research also found that public data from the US showed that hundreds of recent shale gas wells in Pennsylvania have suffered failures that could cause water or air pollution.”
“The research confirms that well failure in hydrocarbon wells is an issue and that publicly available data in Europe on this seems to be sparse,” said Professor Richard Davies of Durham University, and who led the team of academics who undertook the work. “In the UK, wells are monitored by well inspectors but there is no information in the public domain, so we don’t really know the full extent of well failures. There were unknowns we couldn’t get to the bottom of.”
The research analysed every reliable dataset on the 4m onshore hydrocarbon wells that have been drilled around the world since the industry began a century ago, in order to assess the implications for unconventional oil and gas exploitation, including shale gas. The study focused on well failures, in which the cement, steel casing or valves failed to contain the oil, gas and drilling fluids. It noted the difference between internal failures, where gas, oil or other chemicals did not leak into the wider environment and external failures, where leaks did enter rocks, water acquifers or the air.
While a lot of well data is made public in the US, it was not detailed enough for the researchers to distinguish serious and minor well failures. “But in the UK we don’t even have that,” said Davies.
The study, published on Tuesday in the journal Marine and Petroleum Geology, reported that 2,152 wells have been drilled onshore in the UK since 1902. But no producing shale gas wells exist yet in the UK and, for a comparison, Davies said: “It is sensible to look at the data from Pennsylvania.” One dataset highlighed found that 8,030 fracking wells targetting the Marcellus shale in Pennsylvania were inspected between 2005-2013 and 6.3% (506 wells) were reported for internal or external well barrier failures.”