Cuadrilla wants to use more chemicals to improve fracking at shale gas site

pnr 190102 ros wills 1

Tankers leaving Cuadrilla’s shale gas site, 2 January 2019. Photo: Ros Wills

The shale gas company, Cuadrilla, is seeking permission to add new chemicals to its fracking operations in Lancashire.

In details published today, the company said it wanted to change the composition of the fracking fluid so that more sand could be carried into fractures in the shale rock.

This follows news earlier this month that Cuadrilla had fully fracked only 5% of its first well at the site at Preston New Road near Blackpool. Fracking operations, between October and December 2018, were paused at least five times because they induced earth tremors measuring 0.5ML or above. Fracturing equipment has since been moved off the site.

Today’s  application to the Environment Agency also seeks permission to use methanol, an “optimised fracking fluid” and a new biocide. If approved, the changes would additionally make it clear that Cuadrilla can frack each well more than once.

Local opponents of Cuadrilla’s operation described it as a “desperate attempt to revive a dying industry” and said it felt as if they were being “fracked by trial and error”.

This is the latest in a series of changes to the environmental permit for Preston New Road. Cuadrilla submitted its first application nearly five years ago in June 2014. These latest proposals, if approved, would become version nine.

The changes incorporate “operational refinements identified during site operations to date”, Cuadrilla said, and “more precisely reflects the site’s procedures and operational controls”.

A public consultation began today and continues until 20 March 2019.

pnr 181225 ros wills4

Cuadrilla’s Preston New Road shale gas site, 25 December 2018. Photo: Ros Wills

Proposed changes

Frack fluid

Cuadrilla said it was seeking approval for the use of what it called “an optimised hydraulic fracturing fluid” to allow for “operational flexibility during hydraulic fracturing”.

The company’s environmental manager, Nick Mace, said:

“we’d like to modify our fracturing fluid so that more sand can be carried into the shale rock with the water when we recommence hydraulic fracturing operations at the Preston New Road site. To do this we proposed to add some chemicals which have already been approved for use elsewhere in the UK by the Environment Agency.”

During hydraulic fracturing last year, Cuadrilla complained that it had been unable to pump sand far enough into the shale rock without causing earth tremors.

The waste management plan, which accompanied today’s application, said the company wanted to use a more viscous fracking fluid than had been tried so far.

Higher viscosity fluid can transport sand at lower rates. It also helps to initiate fractures and increases the fracture width to allow more space for the sand, the waste management plan said.

The application proposes increasing the concentration of friction reducer in the fracturing fluid from 0.05% to 1%. It also considers the use of gelling agents, at about 4% by volume, to transport the sand along the lengths of the fractures.

So far, Cuadrilla has said it added only the friction reducer, polyacrymalide, and sand to the water to frack at Preston New Road.

The new application lists about 40 hydraulic fracturing fluid additives, described variously as cross linkers, gelling agents, carriers, pH buffer/activator, cleanup/flowback aid, clay control/brine, carrier, gel breaker, delay agent and scale control.

The company said the additional ingredients would remain non-hazardous to groundwater. They were commonly found in food, toiletries and other products used around the home, it said.

Other chemicals

Hydrochloric acid Cuadrilla said this would help reduce fracturing pressure. It would dissolve drilling mud remaining in the wellbore and “facilitate entry of the fracturing fluid from openings in the production tubing to the body of shale”. The company said the acid would be used on the well before fracking. An estimated 3-15m3 per fracture stage would be needed. It would be stored at a strength no greater than 10%, the company said.

Methanol Cuadrilla said this would be used to prevent the formation of gas hydrates during well suspension. An interim decision by regulators has considered methanol non-hazardous to groundwater, Cuadrilla said.

Glutaraldehyde Described as a non-hazardous biocide, Cuadrilla said this was an alternative way of treating bacteria to ultraviolent light

Multiple fracks

Cuadrilla said the new permit would clarify that each horizontal well could be re-entered and hydraulic fracturing may be conducted on more than one occasion. Each re-entry would be individually planned and managed, the company said.

Well workovers

The documents stated that periodic well workovers or other well interventions would potentially be needed at Preston New Road and would be covered by the revised permit.

pnr 181102 Cuadrilla Resources

Gas flares at Cuadrilla’s fracking site at Preston New Road near Blackpool, 2 November 2018. Photo: Cuadrilla Resources

Flaring and nitrogen lift

The waste management plan said propane could be added to help burn gas produced from the initial well test. DrillOrDrop asked Cuadrilla a series of questions about flaring and whether shale gas was being vented at Preston New Road.

The spokesperson for the company said:

“We consider that there is more than sufficient information provided about our application to vary the current permit at Preston New Road. We respect this process and Cuadrilla has nothing further to add at this stage.”


Cuadrilla seeks to reduce the frequency of surface water monitoring to monthly, which was, it said, “more proportionate to risks presented by the site”.

On air quality monitoring, the company is seeking to stop collecting data on a range of pollutants at off-site stations. The substances include methane, carbon monoxide, nitrogen dioxide, nitric oxide, sulphur dioxide, ozone, total petroleum hydrocarbons, VOCs, particulates (PM10 and PM2.5) and dust. Cuadrilla said collection of this data had been superseded by onsite continuous monitoring.


A spokesperson from Preston New Road Action Group said:

“It feels as though we are being fracked by trial and error: this seems like another desperate attempt to resurrect this dying industry.

“How will changing the fracking fluids prevent seismic events? Just more worry for the unfortunate guinea pigs living close to the site.”

Frack Free Lancashire said

“We are concerned (but not entirely surprised) that after years of claiming that the only two chemicals to be used in UK fracking were polyacrylamide and hydrochloric acid, that they should now be seeking, after just one failed frack, to expand the list of chemicals available in their inventory to add to their fracturing fluid.”

The group added:

“Equally concerning is the list in the application documents of 41 potential additives to their drilling fluids of which no less than 14 are described by Cuadrilla themselves as “potentially hazardous”.

“We predicted that the list of chemicals would inevitably be expanded as this project continued and will continue to monitor the situation.”

More questions

DrillOrDrop also asked Cuadrilla for clarification on a range of issues arising in the revised waste management plan. This included questions about drilling muds, the use of methanol and hydrochloric acid, re-fracturing of the wells, fracturing plans for wells 3 and 4, and waste sand. The company was not willing to answer our questions.

Updated 21/2/2019 to increase the number of hydraulic fracturing fluids additives listed in the application

50 replies »

  1. I think it is reasonable that Cuadrilla would want to learn as much as they can about fracturing the Bowland Shale now they have got this far. So I am supportive of their intent & I hope the regulator agrees. It is in the national interest to learn as much as possible during this exploratory phase.

    • According to NICK RILEY: “I think it is reasonable that Cuadrilla would want to learn as much as they can about fracturing the Bowland Shale now they have got this far. So I am supportive of their intent & I hope the regulator agrees. It is in the national interest to learn as much as possible during this exploratory phase.” Thanks Nick for expressing your opinions.
      However the place to “learn as much as possible” is NOT “during this exploratory phase” but BEFORE IT.

      Regarding pathways to watercourses, as I recall Cuardrilla has had a difficult time with water at Preston New Road. It is important to remember that for a long period last year the pad was a giant paddling pool. My understanding was – correct me if I was wrong – that water was gaining access to surface waters in nearby ditches.

      Which brings us to the question of freshwater ecosystems in not only ditches but also via the network of field drains than connect many of the marl pit ponds not far from the drill pad. Lab studies in the USA show glutaraldehyde:
      to have toxic effects on the the tiny freshwater crustacean Daphnia magna which is part of the zooplankton that feeds on algae and the phytoplankton. Daphia is present in the Fylde ponds and along with other zooplankton is part of the food chain for tadpoles of frogs, toads and newts – which are part of the food chain for many species from herons to hydras.

      Regarding humans, according to USA government NIOSH, “the following health effects have been reported in hospital workers exposed to glutaraldehyde: Throat and lung irritation; Asthma, asthma-like symptoms, and breathing difficulty; Nose irritation, sneezing, and wheezing; Nosebleed; Burning eyes and conjunctivitis; Rash-contact and/or allergic dermatitis; Staining of the hands (brownish or tan); Hives; Headaches; Nausea”

      Nick what is the rush all about? Justifying something as being “in the national interest” can be used to justify anything and everything. So what exactly is “in the national interest” for hydraulic fracking in Lancashire? Especially as there are good alternatives to gas, at least for as long as the sun continues to shine and the wind to blow. Indeed I believe “in the world interest” easily trumps “in the national interest” and I trust you too agree.

      Robin Grayson MSc – Liberal Democrat Geologist

  2. Well, Robin I went your link These are all descriptions of direct & high exposure within hospitals to staff working in confined buildings, not in the open air. These are exposures to workers in close contact with this substance. Safety standards are very high for personnel on rig sites with strict mandatory requirements regarding H&S. No-one is allowed to work on site unless they go through obligatory H&S induction at each rig site (each site has unique H&S issues) . As regard run off from the well pad during heavy rainfall periods. First you have to assume that glutaraldehyde is being spilt onto the drill pad, & you forget that under such high rainfall conditions dilution & attenuation will occur. Why don’t you suggest banning road salt? It has decimated the freshwater crayfish in the UK. Or methanol in screenwash, which is very toxic to freshwater organisms. These 2 examples do end up in watercourses all over the UK, even during low rainfall events. So if you are worried about possible spillage of glutaraldehyde getting into a marl pond during periods of very heavy rainfall in 1 location in the UK – you are overstating your case, compared to the commonplace use of road salt & methanol with respect to road transport. Indeed on the road that runs by the PNR site. Furthermore, one can only learn by doing, that is what exploration & testing is all about. Another thing, I never knew the Libdems awarded professional geologist qualifications – so what is a Liberal Democrat Geologist?

    • Nick, from what I’ve read a “Liberal Democrat Geologist” is someone who did a bit of work on geology many years ago but now is Liberally addressing subjects that he doesn’t understand. However, as a Democracy, he is free to express misinformed views. Many who retire have lots of time on their hands and spend that time obsessed with NIMBY issues. Not wishing to be too sycophantic, but since you retired from the BGS, you have continued to be a champion of our aim to reduce GHG emissions. If the protesters of fracking did as much as you we would be in a better place.

      • Hi Judith, thanks for displaying the extent of your knowledge.
        Hi Nick, a few moments ago, I received a complimentary copy from the authors of a peer-reviewed paper that opens up a sustainable solution for removing glutaraldehyde in saline water, using a catalyst under sunlight.

        Here is the reference:
        Soklida Hong, Thunyalux Ratpukdi, Bunleu Sungthong, Jayaraman Sivaguru and Eakalak Khan (January 2019). A sustainable solution for removal of glutaraldehyde in saline water with visible light photocatalysis. Chemosphere, volume 220, pages 1083-1090.

        Here is what the authors say:
        “Visible light photocatalysis by Ag/AgCl/BiOCl is a potential technology for removing Glutaraldehyde in oil and gas produced water due to its exceptional performance under sunlight irradiation. High photocatalytic activity under sunlight is desirable since it provides free energy for irradiation, more importantly when prolonged irradiation is needed.”

        “This study helps in developing a sustainable solution for produced water treatment, disposal and reuse for hydraulic fracturing.” After removing Glutaraldehyde, produced water will be less harmful for disposal or biological processes, which are economical, will become viable for further treatment of the water for potential fracturing reuse.”

        Nick, IMO this may open up the potential for an emerging “Best Available Techniques” BAT regarding the dealing with treatment, disposal and reuse of produced waters containing Glutaraldehyde. More laboratory work is required and scaling up step-by-step.

        Robin Grayson MSc
        Liberal Democrat Geologist

        • Why are you even discussing removing glutaraldyhyde? It’s very easy and a standard process in water treatment. Also, as several papers have suggested it will sort itself out in most subsurface environments if left for a sufficient period of time. So as long as the fracking fluid isn’t doing too much formation damage then one could just wait a little before cleaning up the fractures and that will dramatically reduce the amount of glutaraldyhyde in the produced water. Indeed, it would reduce the amount of flow back fluid as well so a clear winner.

          • Hi Judith, Thank you for your comments.
            “Why are you even discussing removing glutaraldyhyde?”
            I am not discussing removing glutaraldyhyde.
            For me the topic is closed.
            I am satisfied that USA researchers have demonstrated it can be done well eventually.
            If you wish to discuss your ideas do so with them.

            Robin Grayson MSc
            Liberal Democrat Geologist

  3. Somewhat quaint to suggest that the Bowland shale is very different to other shale situations and then to promote that learning could be done BEFORE the exploration stage! How? Sit around a camp fire and have a chat?

    “Scaling up step-by-step”!! Seems that learning can be obtained via practice in some situations but not others.

    Now I see the Liberal Democrat connection.

    • Hi Martin, Thanks tor your comments.

      The Bowland Shale is indeed “very different” to other shale situations. In particular, the Bowland Shale has exceptionally high levels of selenium in it, much higher than expected, and higher than known in USA frackable shales.

      This was discovered by testing samples readily available at the surface at more than 40 locations where the Bowland Shale rocks are at the surface. If you really must, you could sit around a camp fire and have a chat at any one of these locations. Let me know if you would like to have some of the locations.

      “Scaling up step-by-step”!! Seems that learning can be obtained via practice in some situations but not others.
      Yes, you are absolutely right, good thinking, keep thinking.

      Robin Grayson MSc
      Liberal Democrat Geologist

  4. Yep, learning is what testing is about.

    Shame that if you believe the Lib Dems, one day your learning will be free, then a short while later you find there has been a chat, and a few have decided their finances are more important than your finances and your learning is going to cost a great deal.

    (Good job that selenium is not at those levels at PNR, otherwise Cuadrilla would struggle to know whether optimum to mine the selenium or extract the gas.)

  5. I do love this strange fixation upon selenium, which is supposed to be scientific but is the opposite.

    Selenium toxicity in livestock can be produced if animals consume high quantities of forage containing high levels of selenium!

    Oops. Precautionary principle time. Cover the Fylde in drilling sites to protect the livestock.

    • Martin – I agree the fixation with selenium is very odd. Basically, John Parnell and co-workers made some measurements of the major and trace element compositions of a series of Bowland shale samples. The data in itself is rather dull so to create a narrative that would both get the results published and get more citations they brought in the shale gas aspect. They actually conclude Se entering the drinking water isn’t a significant worry because the UK has a good regulatory framework and selenium is easy to remove from water. However, our resident polymath seems to have ignored their argument that it’s not a big deal and has cherry picked arguments to try and scare people into thinking that this is a problem – it isn’t. The only real danger regarding Se from the Bowland would be due to weathering of the Bowland in soils and the transfer of Se into vegetation that then gets eaten by livestock.

      • Hi Judith,

        Thanks for your comments.

        Please note:
        1: The Bowland Shale is very rich in pyrite.
        2: The Bowland Shale pyrite is remarkably rich in selenium.
        3: The Bowland Shale pyrite is stable at depth.
        4: The Bowland Shale pyrite is unstable when fracked.
        5: The selenium (and arsenic etc) are released when pyrite is unstable.
        6: The selenium ends up in the fracking fluids.
        7: The selenium is therefore an issue.

        Please note:
        I decline to respond to any more of your comments.

        Robin Grayson MSc
        Liberal Democrat Geologist

        • Robin, I don’t care if you decline to respond to my comments as you seldom have anything useful in your comments. I guess this reply is a bit if an interesting comment (which may or may not be true) about selenium being housed within the pyrite, which is something I’ve never observed when analysing pyrite from this formation used an electron microprobe fitted with a wave dispersive X-ray spectromenter (accurate enough to around 10 ppm). Maybe you’re just making the assumption that the correlation between selenium and sulphur content is a cause and effect, which is clearly rubbish as uranium is also correlate with pyrite content but is not contained within pyrite as it doesnt fit in the structure.. The stability of pyrite depends on the amount of oxygen in the fracking fluid. Even i it contains oxygen then the rate of pyrite oxidation is very limited as it will be diffusion controlled due to the extremely low permeability of the shale (varies between 10-19 and 10-22 m2). Even if selenium ended up in fracking fluid it is very easy to remove. Anyhow, I’ll let you get back to your amateur geology.

          • Judith – I’ve reason for the lack of Se in the pyrite you analysed could be because it could partition between different morphologies of pyrite. I’ve not worked directly on the Bowland but most black shale contains two forms of pyrite: framboidal and euhedral. The former forms very rapidly at the redocline, which in anoxic sediments is in the water column. The euhedral pyrite forms more slowly within the sediment. It is possible that it is concentrated in one not both of these morpholgies. Did you observe both? Did you analyse both?

            It’s interesting but totally academic as I agree with you that selenium is not a risk one needs to worry about.

            • “The pyrite is the main residence of Se and As”.

              Here is the method of detecting and quantifying Selenium in bulk-rock Bowland Shale:

              “Trace element contents were measured in shale samples using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-MS). Samples of ~30 g rock were milled and homogenised, and 0.25 g digested with perchloric, nitric, hydrofluoric and hydrochloric acids to near dryness. The residue was topped up with dilute hydrochloric acid, and analysed using a Varian 725 instrument (Inductively Coupled Plasma Optical Emission Spectrometer). Samples with high concentrations were diluted with hydrochloric acid to make a solution of 12.5 mL, homogenized, then analysed by ICP-MS. Results were corrected for spectral inter-element interferences.
              The limits of resolution are 0.05 and 10,000 ppm.”

              Robin Grayson MSc
              Liberal Democrat Geologist

  6. Simon,
    It was nearly 25 years ago when I was doing my first post-doc so I can’t remember exactly. However, given that we could only focus the electron beam on the microprobe to 2um I probably analysed the euhedral pyrite.

    What you says makes sense, framboidal pyrite forms via a monosulphide precursors with a high surface area so would probably incorporate more trace elements than the euhedral variety.

    Interesting logic shown by Robin there – tells you that it’s concentrated in pyrite and as proof provides an analytical procedure for measuring the bulk content of rocks instead of one that measures the composition of individual minerals. Anyone would think he was copying and pasting from papers and not really understanding the material 😉

    • Judith, my chemistry is obviously not as good as yours so maybe you can answer something for me. I read that one of the ways to remove Selenium from water is by coprecioitation:adsorption onto amorphous iron oxides – wouldn’t this occur naturally if pyrite was exidized?

      • Simon, I’m not sure – I did some TEM work on colloidal iron oxyhydroxides associated with acid mine drainage as part of a consultancy project a few years ago and they contained a massive array of both major and trace elements

Add a comment

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s