Fracking tremor limit could be raised safely, say scientists

pnr 181024 Eddie Thornton

Opponents of fracking at Cuadrilla’s Preston New Road site, 24 October 2018. Photo: Eddie Thornton

Two scientists have said the rules on fracking-induced earth tremors could be relaxed with little risk to people.

Under the current traffic light system, fracking must stop for 18 hours if the operation induces seismic activity of 0.5ML (local magnitude) or above.

Now Dr Brian Baptie, of the British Geological Survey (BGS), and Dr Ben Edwards, of Liverpool University, argued that the limit could be raised safely to 1.5ML, which, they said, was unlikely to be felt.

Their proposal, made in a media briefing earlier today, was welcomed by Cuadrilla, which triggered 57 earth tremors when it fracked in Lancashire last year.

But opponents of Cuadrilla’s operations said people were less concerned what was felt at the surface and more about what happened at the depth of the wellbore. Campaigners in Lancashire said they would consider a legal challenge if the government gave into industry lobbying for a higher limit.

Cuadrilla’s fracking operations at Preston New Road triggered three tremors which exceeded the 0.5ML red traffic light level during fracking last year. Another four passed the 0.5ML threshold after fracking had finished. Two of the tremors, measuring 1.1ML and 1.5ML were felt by people living and working locally.

The company previously called on the government to raise the 0.5ML threshold. It pointed to higher limits of 4ML in Canada and 2.7 in California.

But the energy minister, Claire Perry, has said there are no plans to relax the rules. In a letter to Cuadrilla in November 2018, she said the current system was “fit for purpose” and there was “no intention of altering it”. She repeated this position in a recent parliamentary answer.

181214 bubble chart refracktion

Seismic events at Cuadrilla’s Preston New Road shale gas site up to 14 December 2018. Source: Refracktion

Dr Brian Baptie, head of seismicity at the British Geological Survey, said today:

“The existing regulations are really quite conservative. They are set at a level of earthquake that is really very unlikely to be felt.

“So something like 1.5 is a level of earthquake that is not going to be felt widely by people – I think it is something we ought to have a look at.”

He said:

“When earthquakes occur, they cause shaking, so could that shaking damage the wells? I think the risk of that is vanishingly small – it is negligible for such small events”.

Dr Baptie contributed to a government-commissioned report on Cuadrilla’s earlier experience of fracking-induced seismic activity when its first frack at Preese Hall in 2011 prompted earthquakes measuring 2.3ML and1.5ML. That report recommended the current red traffic light of 0.5ML.

The other scientist, Dr Ben Edwards, has contributed to material for Cuadrilla and the government. He said:

“If you want to mitigate any chance of felt activity, similar in vibration magnitude to a building site, we have the correct traffic light system.

“But if you want to go to a risk-based approach, where you allow events that do not pose any risk to humans or structures, then there is scope to review the current system, that could be raised to 1.5 and that would still arguably be conservative.”

Dr Edwards was responsible for recent government-commissioned research which likened the effects at the surface of a 1.1ML tremor to a 1kg bag of flour falling to the floor, and a 1.5ML tremor to a dropped honeydew melon.

Frack Free Lancashire said this evening:

“It seems to have taken the industry spin doctors longer than expected to find a couple of academics prepared to make their case for them.

“However, both of these researchers still appear to be inexplicably fixated on whether a tremor can be felt at surface.

“The Traffic Light System (TLS) was devised, in conjunction with Cuadrilla themselves, to protect the public from the potential subsurface impacts of fracking. It is based on an acceptance that the seismic events (which fracking appears to inevitably unleash in the UK) cannot be constrained by turning off a tap, and that they may get progressively more frequent and larger after the warning level is exceeded and work is stopped.

“The government and local Conservative MP, Mark Menzies, have already stated their opposition to increasing the TLS limits. Claire Perry – the energy minister – stated that would be a “foolish politician who would do things that would be considered to be relaxing regulatory standards when we are trying to reassure people about safety.”

“If the government were seen to be caving in to industry lobbying after they have so clearly demonstrated that they are unable to control the seismic activity caused by their operations, we will consider seeking a legal challenge.”

John Sauven, executive of director of Greenpeace UK, said:

“This is a barely disguised attempt to mislead people. The main concern over tremors caused by fracking is not damage caused at the surface but damage caused to the well.

“This is likely to be near the epicentre of the quake. We know this is a risk. It is exactly what happened at the UK’s first fracked well at Preese Hall in 2011. The well bore damage was observed after quakes which caused no damage at the surface.”

A spokesperson for Cuadrilla said:

“We were pleased to hear this. We have collected an extensive data set from our operations at the shale gas exploration site in Preston New Road, Blackpool, including the most comprehensive micro-seismic data set ever collected at a shale site.

“We have shared this with the relevant regulators and experts to enable further understanding of how best to safely and effectively progress this important industry”.

51 replies »

  1. This is a report from California, where serious seismicity is an issue yet they still drill. Very few issues, even in big events.

    It strikes me as odd that a small localised event could cause an integrity issue in the crucial sealing parts of the well that are a long way away. There is no case of this happening anywhere, Yet again we have people with no knowledge passing comments on matters they do not understand. No serious drilling engineer has an issue with this. This 12 years experience senior engineer who has worked with well integrity issues at a senior level says these concerns are BS.

    • The BGS state,

      ‘We note that the causative fault has not actually been identified, and more generally that there is only a limited understanding of the fault systems in the basin’

      ‘Earthquakes in the magnitude range 2 to 3 ML require only relatively small rupture areas, and so can occur on small faults’

      ‘There might be other comparable faults at reservoir depths throughout the basin’,

      Sounds like the 12 year experience senior engineer knows nothing of the fault system of the Bowland Shale and therefore cannot comment on potential well integrity issues associated with fracking in the Bowland shale.

      Sounds like a BS reason to offer to try and promote a higher threshold.

      • The point is that it doesn’t matter than one can’t map every fault at depth when one knows that a 2 to 3 ML tremor at such depth is irrelevant.

      • Of interest to Claire Perry will be the Edison report ‘AJ Lucas Goup Dominant Bowland Shale Position’ published in April 2018.

        As Claire was not initially informed by Cuadrilla of the need to alter the seismic threshold it seems strange that an in depth report appears to not reference the fact that there is a 0.5 M threshold in place.

        It states

        The new regime includes the requirement for seismic monitoring of each well site area and a system under which operations are
        halted if seismicity reaches a level greater than 1.7 ML (Operation has to stop if 1.7 is exceeded, the well bled off and then the seismicity monitored until zero events for at least 10 days, then the operation can recommence, otherwise the operation has to be aborted and the seismic risk reevaluated)

        I doubt the report would have shown a 67% success rate if the factual 0.5M threshold was used. Investors take note.

        As the report includes in depth findings of Cuadrilla,s workings why do you suppose it missed off the very important part about the 0.5M threshold?

        It appears important information is being selectively distributed.

      • John. The 2012 Report on the Preese Hall Earthquakes names Dr J Baptie of the BGS as one of the three authors. That was the Report that concluded that the TLS red level should be 0.5ML and Cuadrilla assured us for the last 6 years that would comply with this.Gold Standard indeed. Suddenly their “expert” says that level is far too low and likens earthquakes to falling melons and bin wagons. This “expert’s” name? Dr J Baptie of the BGS.

    • Just read Ken’s report from California which talks in glowing terms about injection wells without once mentioning the contamination issues that they have caused. Historically California has derived almost all of its drinking water from snow melt, which has meant that they didn’t have legal protections in place for the ground water.
      The drought of recent years coupled with shrinking ice caps in the mountains has caused them to start to look at their groundwater and have belatedly discovered that much of it has been polluted beyond use by the oil and gas industry.

      A pro-industry report from an area that doesn’t understand contamination is not evidence to support what should happen in the UK. The fact remains that we need to leave most of the known carbon in the ground which means that there is no point in seeking out desperate sources of additional carbon. Reducing the demand for gas is far more cost efficient than fracking to increase production.

  2. This is all irrelevant, WE DO NOT NEED SHALE GAS. And before the pro frackers start screaming their boring arguements , I do have gas central heating so what. There is plenty of gas available without turning our countryside into an industrial landscape.

    • Jon – it looks like you’ve been taken in a little by the scaremongering. Have you actually visited many sites where unconventionals are being produced? I’ve visited loads of them and the picture you an industrial landscape that you write about is about as far from the truth as you can get.

      • To produce the amount of gas needed to make it worthwhile for the gas companies there would need to be hundreds, yes hundreds of fracking sites across the country. To say that this wouldn’t result in an industrial landscape is simply a lie. WE DO NOT NEED SHALE GAS.

        • So you haven’t been to places with lots of wells have you Jon? The Schoonebeck oil field in the Netherlands might be a start – it has an order of magnitude more pads than any shale gas development will in the UK – go there – have a look. You could also go and look at some of the oil fields in Austria – massive well density but one struggles to see the infrastructure. Same is true of national parks in Canada etc etc. Just face it Jon – you’ve got an imagination about what things might look like but you don’t have any knowledge of it do you Jon?

  3. The point is not whether it will cause damage at the surface. It’s whether it will cause damage to the well, as happened at Preece Hall in 2011. These scientist, who are paid by the Oil and Gas Authority, should know better than to put out such deliberately misleading information. This shows the desperation of the industry as fracking continues to be still-born in the UK.

    • Ellie – wells are damaged all of the time in the industry. In fact, the elongation of boreholes due the action of subsurface stresses is totally inevitable. Luckily the oil and gas industry know what they are doing so leakage as a result of such deformation never occurs except in the minds of the clueless

  4. I am sure you feel you know more than they do, Ellie, but I suspect that is not the reality.

    Desperation? Ermm, no. Just shows that the real specialists are involved in appraisal. Somehow I prefer that to the antis uniformed speculation.

  5. To produce the amount of gas needed to make it worthwhile for the gas companies there would need to be hundreds, yes hundreds of fracking sites across the country. To say that this wouldn’t result in an industrial landscape is simply a lie. WE DO NOT NEED SHALE GAS.

    • Also Jon – what do you consider worthwhile? For instance, would it be worthwhile having a gas well in your village that supplied sufficient gas to fill the gap when there wasn’t enough wind or sun to produce sufficient energy to heat your home? In terms of an industrial landscape, I’ve visited communities in the very west of Germany that have wind, solar, biogas, biodiesel, conventional oil and unconventional gas. Guess which one is visually the most intrusive and which one the least?

        • Sherwulfe – I’m rather hoping that we will develop and effective energy storage system in the next few years and increase the efficiency of wind, solar, tidal etc. I’m even optimistic about nuclear fission. I’d also hope that we would increase our energy efficiency. However, if that doesn’t happen I would estimate we have enough gas for at least 500 years. I’m fully aware that we need to stop using fossil fuels before they run out. I’ve just not heard a logical argument as to why buying gas from other countries with worse HSE records, increased methane losses, and higher CO2 emissions from transportation and compression will help us out.

          • North sea doing very well

            Between 10 and 20 billion boe’s to go at.

            20 years supply should be enough to see us through.


            If you still can’t sleep at night start protesting to the Government to stop exporting more home grown gas than we import in LNG.

            Sounds like a much more logical solution than spending 9 years toiling over an expensive unreliable shale gas industry that the big players think is a waste of time and has only produced a 10 second propane burst at the cost of tens of millions.

          • Do you you honestly think other countries will suddenly shut down their wells, as a good will gesture and thus not add to the fossil fuels produced, if we produce our own gas. In any case, the industry here have admitted the gas will be sold on the open market to the highest bidder. It won’t be exclusively English – England being the only part of the UK where the Tory government is still crazy enough to support it.

            • Pauline – like everything else demand dictates supply. As long as prople demand it there will be a supply, until it runs out of course in 300 years or so.

              You lot need to cut demand not waste your time on small suppliers, unsuccessfully it would seem based on losing Public Inquiry I can recall.

  6. Martin. ” HMRC calculate decommissioning N Sea oil and gas rigs could cost taxpayer £24billion. How much do you imagine cleaning up after commercial fracking involving hundreds of pads will cost the taxpayer? The shale companies are being very cagey about it . Th fact that every Cuadrilla pad is named as a separate limited company doesn’t inspire much confidence in what would happen in the event of them going bust.

  7. I remember Cuadrilla’s Egan bragging he’d be happy to live on the fracking pad at Preston New Road with his family!

    Only time I’ve seen him anywhere near was at the all weather pitches at Mill Farm, AFC Fylde’s home ground smooching up to some high ranking police officers.

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