The British Geological Survey (BGS) has published new research which it says will reduce the risk of earthquakes and borehole damage caused by fracking.
The paper published in Marine and Petroleum Geology shows that the use of borehole imaging can help improve the understanding of the in-situ stress orientation and sets out the implications of this research for fracking.
The research was triggered by the expert panel report on fracking from the Royal Society and Royal Academy of Engineering which recommended that a complete review of stress data for the UK was undertaken.
As a result, the BGS is now recommending that all new boreholes drilled for shale gas are logged by borehole imaging tools to better understand in-situ stress.
Authors Andrew Kingdon, Mark Fellgett and John William used BGS data from over 90 boreholes from the coal and oil industry where full scanning had been undertaken. This study identified features in 37 of these and compared this new data with the 1990s data and, although it has not changed the basic stress orientation, the authors have said that this new analysis has massively decreased the uncertainty of borehole breakouts.
According to the BGS, this understanding will help in assessment of the in-situ stress orientation, ensuring that regulators assessing well safety have the best data available to allow them to make properly informed decisions about borehole integrity. The BGS hopes this will give the Department of Energy and Climate Change and the Oil and Gas Authority better information to properly assess the risks of any fracking proposed in new boreholes.
BGS director of science and technology Mike Stephenson said: “This research is crucial to the regulators and the oil and gas industry as it is an easily applicable technique that can highlight parts of boreholes that may contain evidence of stress that is already present in rocks before fracking.”