Research

“Significant knowledge gaps” makes forecasting fracking earthquakes “a scientific challenge” – BGS

Forecasting earthquakes caused by fracking is still “a scientific challenge”, the British Geological Survey (BGS) said in a report published today.

Relative size of earth tremors induced by fracking at Cuadrilla’s Preston New Road site, 15-29 August 2019. Chart: Refracktion

The BGS said there was high-quality data in some parts of the UK. But limited exploration data from other areas meant there was “significant gaps” in our knowledge of shale gas formations in England.

More data was needed from some shale gas basins to allow earthquake forecasting methods to be applied more widely, the BGS said.

The report, commissioned by the government in April, said hydraulic fracturing can trigger earthquakes large enough to cause structural damage, which were not predicted in advance.

It did not appear to justify today’s formal lifting of the moratorium on fracking in England or suggestions that the government would review relaxing the regulations on earthquakes.

In August 2019, nearly 200 people reported damage to homes to the BGS from a 2.9ML earthquake caused by fracking by Cuadrilla at Preston New Road in Lancashire.

The moratorium has been in place since November 2019 after ministers concluded that earthquakes caused by fracking could not be predicted or controlled.

Forecasting challenge

The BGS review said:

“Forecasting the occurrence of large earthquakes and their expected magnitude remains a scientific challenge for the geoscience community. This is the case for both tectonic and induced earthquakes.”

Methods used to estimate the strength of induced earthquakes do not account for the possibility of earthquakes that occur after operations have stopped, the BGS said.

The largest earthquakes caused by high volume fracking at the only three wells in the UK all happened after pumping had stopped. These operations were all carried out by Cuadrilla in Lancashire. The earthquakes measured between 1.5ML-2.9ML.

The BGS said adapting methods used to forecast tectonic earthquakes had showed “some promise” in forecasting patterns in fracking-induced seismicity.

But it said more work was needed to understand these methods:

“It remains challenging to identify and characterize faults that could host seismic events of magnitudes up to 3.0 even when using 3-D seismic reflection survey ahead of operations. These may only be revealed by seismicity recorded as HF [hydraulic fracturing] operations are ongoing.”

Gaps in knowledge

The BGS said modelling of faults that could rupture during fracking required accurate mapping and knowledge of rock stresses and pore pressures. It said:

“While this information is available in areas with unconventional hydrocarbon potential such as the Bowland Basin, more data is needed from other basins to apply this more widely.

 “Limited exploration data from other basins with unconventional hydrocarbon potential of the UK means that there are significant gaps in our knowledge of sub-surface structure of potential shale resources in these places.”

The BGS said the Bowland Basin in Lancashire was complex with a wide variety of fault styles and scales.

Referring to other parts of England, the BGS said:

“Existing data suggests that these areas share a complex depositional and structural history, with the possible exception of the Gainsborough Trough and Cleveland Basin”

Last week, IGas reported that the Gainsborough Trough, in Lincolnshire and Nottinghamshire, was less complex than other parts of the UK and had a “significantly reduced risk of induced seismicity”.

 Traffic light system

The BGS made no specific recommendation on relaxing the traffic light system, which require fracking to pause if earthquakes reach a red-light limit of 0.5ML or above.

It said traffic light systems “remain a useful tool for the mitigation of risks from induced seismicity”.

But it did say red-light limits in other countries usually resulted in a complete cessation of operations in a well, rather than a brief pause, because of the increased risk of larger magnitude events.

It also said:

“red-light thresholds should be chosen to ensure that the probability of the scenario to
be avoided, e.g., disturbing or damaging ground motions, is at an acceptable level. Amber light thresholds should be chosen as much as two magnitude units below the red-light threshold.”

Consistent risk targets

The shale gas industry has frequently complained that its earthquake regulations are stricter than for other industries.

The BGS said consistent risk targets “could be considered for all energy-related industries that present a risk of induced earthquakes”.

More DrillOrDrop reports on lifting the frackng moratorium

Government says people living near fracking sites should tolerate more risk and disturbance in the national interest

Tory anger at lifting fracking moratorium – what MPs said in parliament

Reaction to fracking go-ahead

12 replies »

  1. And not forgetting the cluster of “seismic events” at Newdigate, a few miles away from the Horse Hill oil site, as was once known as the Gatwick Gusher. These were controversially and unconvincingly dismissed as natural events .

  2. The BGS are presenting similar problems as the founder of Cuadrilla who has recently stated,

    “Unlike the gas-bearing shale deposits in the US, the shale resource in the UK is “heavily faulted and compartmentalised”, making it far harder to exploit at any scale”
    and
    “It’s very challenging geology, compared with North America”

    Liz and Jacob would do well to listen to the science from the experts.

    • Absolutely John,
      Moreover, the population density of the Fylde is 491/ km2.
      The population density of the Pennsylvania (Marcellus shale) is only 112/km2.
      So on the Fylde, more human ‘receptors’ will be exposed to the increased risks and adverse health impacts from each fracking site.

  3. Convinced me, Malcolm. After all, the antis regularly call for scientific rigor and that was applied. I seem to remember there were one or two outliers from the large consensus, but that is pretty standard.

    I could also look at records since that time and find how many seismic events have occurred across the UK. I suspect a great number, which will have been missed by most people in the localities.

  4. ‘Look’ at these natural occurring seismic events over the last 3 months! Did your David Smythe predict all these before he woke up every morning?
    Earthquakes around the British Isles in the last 60 days:
    https://earthquakes.bgs.ac.uk/earthquakes/recent_uk_events.html

    EARTHQUAKES
    On 1 April 2018, an earthquake struck near Newdigate in Surrey. 57 earthquakes have been reported on the British Geological Survey website and additional small tremors have been analysed, bringing the total to around 170 at the time of writing.

    Cause of the quakes
    In October 2018, the Oil & Gas Authority (OGA) hosted a workshop to look into the cause of the quakes, which was attended by academics and regulators and chaired by the British Geological Survey. The report of the workshop concluded that there was no causal link between the seismic events and oil and gas activity.

    The strongest earthquake so far was given an intensity of 5 and 1,600 people reported feeling it to the British Geological Survey.

    • Francis Egan just on radio 4 stating he ‘hasn’t heard’ that the BGS state that there may be as little as only 5 years supply of gas. His figure was 50 years.
      You would have thought he would be interested in the findings of the BGS.
      Obviously not

      • possibly the angels share of the reduced assessment on UK shale gas, is like a purple unicorn, and reads the same as books of facts written by gayzer frackman?

        Research in induced seismicity settings in the USA and Canada suggests that on average around 1% of Hydraulically Fractured wells can be linked to earthquakes / tremors with magnitudes of 3 or greater, although in some areas of the USA and Canada the percentage of wells associated with induced earthquakes ‘could’ be higher.

          • For the sake of accuracy here is the actual text from the BGS report regarding Hydraulic Fracturing Induced Seismicity (Secrion 6)

            ‘In this section, we compare induced seismicity from hydraulic fracturing of shales in the UK, with that observed in the USA, Canada and China, to answer question 6. This includes references to some research that is important for context. Key findings include:

            The rates of HF-induced seismicity in other countries where shale gas production has been ongoing for many years are observed to vary widely.

            Overall, given the large number of wells with HF operations, there are relatively few published cases of HFIS.

            However, in some areas the percentage of wells associated with induced earthquakes can be as high as 30%.

            HF can trigger earthquakes large enough to cause structural damage. These events were not predicted in advance of operations.

            The limited number of HF operations in the UK means that it is difficult to make a valid comparison of the rates of occurrence of induced seismicity with elsewhere.

            Despite a large number of HF operations in wells in different basins across the USA and western Canada, only a relatively small percentage of wells can be linked to earthquake activity. Some basins show no cases of induced seismicity at all despite similar amounts of HF activity. In basins where there is induced seismicity associated with HF, it is often associated with some wells but not others.

            In the USA, where around 1.8 million HF operations have been carried out in approximately 1 million wells (Gallegos and Varela, 2014), there are relatively few published cases of HF induced earthquakes that were large enough to have been widely felt (e.g., Holland, 2013; Friberg et al., 2014; Skoumal et al., 2015a). Skoumal et al. (2015b) estimated that approximately ~0.35% of ~850 unconventional wells in Ohio had induced seismicity large enough to be detected (M >2). Further analysis in Ohio by Brudzinski and Kozłowska (2019) increased this to ~2.7%. In Pennsylvania and West Virginia, induced seismicity was associated with ~0.05% and ~0.3% of HF wells, respectively (Skoumal et al., 2018b; Brudzinski and Kozłowska, 2019). Skoumal et al. (2018a) found that ~1.8% of 12,000 HF wells in Oklahoma between 2010 and 2016 were correlated with seismicity.

            Atkinson et al. (2016) found that only ~0.3% of horizontally drilled HF wells in the Western Canada Sedimentary Basin (WCSB) were associated earthquakes with magnitudes greater than 3.0 Mw. Ghofrani and Atkinson (2020) developed a statistical model of the likelihood that horizontally fractured wells in the WCSB will trigger earthquakes with magnitudes greater than 3 and mapped how that likelihood varies spatially. Their results showed that from 14,046 HF wells with multistage hydraulic fracture treatments, the regional average probability of earthquakes with M ≥ 3 within a 10 km radius of a HF well is 0.010 to 0.026.

            However, in some areas the percentage of wells associated with induced earthquakes can be much higher. Some of the most notable examples are shown in Figure 6 and listed in Table 1. These include documented cases from the USA (Oklahoma, Texas, Ohio), Canada (Alberta, BC), the UK and China. Schultz et al. (2018) found that ~15% of HF wells within the Kaybob region of the Duvernay play (Alberta) were associated with induced seismicity. Kozłowska et al., (2018) found that between 10% and 33% of HF wells in four ~20 × 20‐km regions of Ohio had induced earthquakes. Skoumal et al. (2018a) finds comparable ratios in four regions in Oklahoma. Shemeta et al. (2019) found that 7.7% of HF wells in Oklahoma were associated with earthquakes of ML ≥ 2, with rates as high as 19.5% in some areas. In the Bowland Shale Formation (UK), HF operations have only occurred in three wells, but these have produced events with maximum magnitudes of M = 2.3, 1.6 and 2.9 respectively (Clarke et al., 2014; Clarke et al., 2019).’

            https://www.gov.uk/government/publications/review-of-the-geological-science-of-shale-gas-fracturing

          • Fracking is neither dangerous, nor a fantasy. Over the last 40 years over 200 wells have been hydraulically fractured in the UK. It is also used in the United States, where it contributes 0.2% of GDP secures their energy needs and helped make them an energy exporter for the first time in decades.

  5. I am no expert but I am curious to know what the water composition and/or acoustic technology is entering any injection wells either here or on other sites versus the gases and minerals dissolved in the frack water coming out of the production wells. The water carrier removing this frac water is paid to remove contaminated water for environmental purposes and within this water are dissolved gases and minerals also worth something. Good for them I suppose. But what if there was an acoustic technology involved in the frack process to cause more gas to be absorbed ( also emitted via leakage as global emissions I assume) and the value is removed untaxed and unnoticed? Is this possible? Look on youtube at a glass of Guinness fizzing up and degassing when it is placed on an ultrasonic/acoustic plate…what companies take away this “waste”?

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