A professor at Edinburgh University has called for more research on the risks of disposing of fracking flowback fluid by re-injection before it is used in the UK.
Stuart Haszeldine, a specialist in the geochemistry of fluids in sedimentary rocks, warned:
“Lessons from the US, where the process has been linked to induced local seismicity and environmental contamination due to poor well construction, have to be learned and not repeated.”
In an article published yesterday (22/1/2016), Professor Haszeldine and Edinburgh colleagues Megan O’Donnell and Stuart Gilfillan, said the disposal of large volumes of contaminated flowback fluids could soon be allowed in England and Wales.
And they warned:
“There is no established track record in the safe tratment of such waste water in the UK”
“If the UK is to dispose of high-volume flowback fluids from shale gas by using re-injection into geological formations, much further research into the potential risks of the process.”
The disposal of waste water from fracking is one of the most controversial aspects of the process. Opponents have argued that the alternative to re-injection – treatment at specialist facilities – will lead to increased traffic. There are also questions over whether the UK has suitable treatment works. An energy consultant argued this month (See Waste treatment causes an impasse for shale gas at the end of this post) that there were currently no treatment works in the UK willing or able to take fracking waste.
“Loophole” on flowback re-injection?
According to Professor Haszeldine and colleagues, new draft guidelines by the Environment Agency, issued in November 2015, show what they call “a significant shift towards the potential permitting and operational use of re-injection wells for the disposal of large volumes of contaminated flowback fluids in England and Wales”.
The Environment Agency’s Technical Guidance document, published in 2013, stated “Disposal of flowback fluid simply by re-injecting it into the shale strata is not permissible under groundwater protection legislation and isn’t considered further here”.
Under the new guidelines, the Environment Agency said it would “generally not permit the re-injection of flowback fluid for disposal into any formation”.
But the authors said the EA had created a loophole by stating: “Re-injection of flowback fluid for disposal is not necessarily prohibited and may be permissible where, for example, it is injected back into formations from which hydrocarbons have been extracted and will have no impact on the status of water bodies or pose any risk to groundwater.”
“The potential permitting of injection for flowback fluids in England and Wales is particularly concerning as there is a complete lack of research on the compositions of the waste water and potential chemical reactions in the subsurface.”
Conventional versus unconventional
The article acknowledged that 99.9% of produced water from UK conventional onshore oil and gas was re-injected in 2014-2015.
But it pointed to big differences between waste from conventional and unconventional operations.
The authors said that in conventional operations, the produced water is almost entirely formation water and this is re-injected into the same formation it came from. The volume of reinjected water is less than, or similar, to the volumes of pore space underground.
But in shale gas wells, flowback fluids would be re-injected into different geological formations. And the volumes would be larger because no oil or gas had been removed before re-injection. This could lead to increased pressure, release built-up stresses and produce an earthquake, the authors said.
They also argued that the chemical makeup of flowback fluids from fracking were very different to that of produced waters associated with conventional hydrocarbon extraction. Fracking flowback had the potential to contaminate groundwater, they said.
The authors said the seismic risk of re-injecting flowback fluid must be assessed and, if it were carried out in the UK, it must be carefully monitored. They added:
“We also strongly recommend that a research-based code of best practice, from which the regulators can adapt the legislation to reduce the risk of environmental contamination must be established before any flowback fluid re-injection permits are granted.”
UK failing to learn U.S. lessons on fracking waste water, Megan O’Donnell, Stuart Gilfillan and Stuart Haszeldine, EnergyAndCarbon.com 22/1/2016
Waste treatment causes an impasse for shale gas
An alternative to re-injection would be treatment but John Busby, an energy consultant, writing this month, said:
“There is currently no treatment works in the UK able and willing to take in fracking wastewater”.
“The lack of suitable water treatment facilities in the UK has created an impasse for fracking test drilling as there will be no means of disposing of the occurring wastewater.”
He said the only high volume hydraulic fracture carried out in the UK resulted in 8,000 cubic metres being taken to the United Utilities works at Daveyhulme in 300 tanker movements.
Fracking wastewater, John Busby, 14/1/2016
Updated 5/2/16 to amend quotes changed to the original article after publication.