guest post

Everything you always wanted to know about acidising

Wressle drilling 2014 Egdon

Flow testing at the Wressle oil site in Lincolnshire

Guest post by Kathryn McWhirter

Tomorrow (11 January 2017), North Lincolnshire Council is expected to decide on a plans for oil production at Egdon’s site at Wressle, near Scunthorpe.

The application includes proposals for the little-discussed process of acidisation.

In this Guest Post, writer and campaigner Kathryn McWhirter investigates the use of acid in the onshore oil and gas industry.

The first part of her post is an introduction to the process. If you want to read more, Kathryn McWhirter has made a detailed study based on scientific papers, industry training manuals, promotional literature for new, patented technologies, and discussions with engineers, geologists and scientists.

It’s time to talk about acid

Finally, we’re all talking about shale gas and fracking.

And we are ignoring the threat quietly posed by other extreme forms of gas and oil exploration. It’s time to broaden the discussion, and talk also about acidising, or acidisation.

Acidising, little understood outside the oil and gas industry, is coming to communities from Sussex and Surrey to Lincolnshire. Acidising poses its own threats, and is likely to lead on to fracking at a later stage.

Planners and councillors are already facing decisions on applications for acidisation, yet they don’t, for the most part, understand the science and the risks, nor the likelihood of proliferation – the very large number of wells that could be drilled.

The oil and gas industry seems to do its best to confuse, using obscure wording in planning applications. Planning applications may not mention acidising by name. ‘Well stimulation’ sounds relatively friendly. The application at Markwells Wood in Sussex by UK Oil and Gas Investments plc calls it:

‘a new non-massive fracking-based reservoir stimulation technology that does not involve massive hydraulic fracturing’.

Few studies have addressed the potential problems. In the UK there is little regulation or oversight.

Fracking is for shale. Acids are used to dissolve unyielding limestone or sandstone to make pathways for oil or gas flow. It’s not new. But like fracking, acidisation is now planned on a far bigger scale, down long, horizontal wells, a great multiplicity of wells. Many co-additives are needed to make the acids work effectively – a greater concentration of chemicals than are used in fracking fluids for shale.

Acids in question range from hydrochloric (for limestone) to the super-dangerous hydrofluoric (for sandstone). Acidising can be done at low pressure, or, like fracking shale, at major pressure that fractures rock. Not so long ago this would have been called an ‘acid frack’, but the government re-defined fracking in 2015 on the basis of the amount of fluid used rather than rock-cracking pressure.

If it’s not officially fracking, none of the new rules and regulations developed by government under oil and gas industry guidance will apply – so oil companies will feel free to drill and acidise in National Parks, Sites of Special Scientific Interest, Areas of Outstanding Natural Beauty and so on, at depths of less than 1,000 metres, without any of the baseline monitoring prescribed for fracking.

‘Acid fracking’ is not the only expression government and industry are keen to avoid in their attempt to make this extreme form of oil and gas extraction a non-issue for public, planners and press.

Conventional versus unconventional

There is also a game of words around the terms ‘conventional’ and ‘unconventional’. There are no statutory definitions for these terms. Geologists and engineers use the term ‘conventional’ to describe a geological formation from which oil or gas flows easily. ‘Conventional’ formations are permeable, so that one well can drain the rocks over a wide area.

In ‘unconventional’ formations, the oil or gas remains trapped in minute globules in the rock until ‘stimulated’ or released, by fracking, acidising or other means. ‘Unconventional’ formations are also known as ‘tight’ formations. At Balcombe and Horse Hill, for example, in Sussex and Surrey, the micrite limestone is ‘tight’ and ‘unconventional’.

Yet the government declared all the PEDLs across the Weald to be ‘conventional’ when the announcement of the 14th round of new petroleum exploration and development licences was buried in the Christmas wrapping paper of 2015. Meanwhile, oil and gas companies call their ‘prospects’ in the Weald ‘unconventional’ when talking to potential shareholders, but imply that they are ‘conventional’ when speaking to local communities.

Arguments against acidisation

Most of the negative arguments against fracking can also be made against acidisation – plus many more for ‘stimulation’ with hydrofluoric acid, one of the earth’s most dangerous chemicals.

UKOG CEO Stephen Sanderson has explained to shareholders that acidised wells would, like high-volume hydraulically fracked wells, need to be ‘back to back’ at regular intervals across the Weald to access as much as possible of the oil – since the oil will flow only from the ‘stimulated’ parts of the rock near the wellbore. This proliferation of wells, industrialisation of the countryside, is one of the main reasons to oppose unconventional drilling.

As with fracking for shale gas, there are questions over human and animal health, environment and climate.

Chemical use is even greater in acidisation than in hydraulic fracking. Solid and liquid waste will be toxic, highly saline and radioactive, a risk to groundwater, surface water and soil should accidents occur.

There will be potential air pollution from flares, potential groundwater pollution via faults, fractures and the well bore, noise and light pollution, traffic, the risk of spills and other accidents. Storm and floodwater may spread pollution. Wells may be acidised repeatedly. There is little research on the subject of repeated acidisation and the cumulative effect on our environment and human health. On-site workers and local communities are particularly at risk. Significantly, Portsmouth Water, the CPRE and the local Environment Agency objected to UKOG’s application to drill and acidise at Markwells Wood, West Sussex.

Fracking seemed enough to get our heads around. But the general public, campaigners, planners, water companies, politicians and regulators now all need to put acid on their agenda.

They should also think critically ahead and understand that, although initial planning applications may seek to acidise at below fracturing pressure, production stage will almost certainly require acidisation at pressure sufficient to fracture the rock.

Link to detailed study

To find out more, Kathryn McWhirter has carried out a detailed study of acidising. It is based on scientific papers, industry training manuals, promotional literature for new, patented technologies, and discussions with engineers, geologists and scientists.

37 replies »

  1. Following my “attempt” at humour to try and get around the problem some have with basic science, there is an interesting “Twilight Zone” in this whole debate at the moment.

    It seems the policy of the antis is still to pursue the previous agenda, which probably raised money to continue the “fight”. Now, with Ineos entering into the arena the whole game changes. I would suggest, they will have all the science on their side, they will have strong PR at a local level and will probably make certain locals are well compensated for inconvenience. I would not be at all surprised if they did not separate this part of the business so that locals could actually become share holders. Additionally, they have already invested hundreds of millions £s to utilise fracked gas at Grangemouth, making themselves a profit but also securing thousands of good jobs and a big tax contribution to the Chancellor. Queen Nic has made it impossible for them to acquire fracked gas from Scotland, what a political blow if they then started to extract fracked gas in England for use at Grangemouth! Would sit alongside oil at $110/barrel. Devolution plus incompetence will not bring independence. (History would suggest exile, or something a little more final.) I suspect Westminster will have seen the value of this situation, even if it might have needed to be underlined.

    • Your comment that Ineos will have ‘all the science on their side’ … just take a look at the extensive set of research papers on this site. There is a LOT of valuable scientific research that clearly points out the considerable dangers of unconventional oil extraction but without the considerable resources of the oil lobby it gets scant publicity. Take a look Martyn then prove the strength of your feeling by moving next to a fracking site.

  2. please could we have likes or dislikes so we can give support to the people who are not working for the PR companies or the shale gas industry . If Fracking was safe why would millions of pounds be paid to PR companies to convince us it was safe when even minimum research would prove otherwise . I wonder how much a PR company was paid for the 3 words NO WIDESPREAD SYSTEMIC contamination ………. in the U.S. .That’s been blown apart now , thank God there are still a few people with integrity left in the U.S. 5.3 trillion dollars spent on subsidising fossil fuels in 2015 , the same amount spent on the planet’s human health care . The fact that the Halliburton Loophole exists is further evidence of the kind of entities that promote this filthy polluting industry

  3. Perhaps millions of pounds are spent on PR because basically very few of the public know absolutely anything about fracking, and there are also those who wish to say “you were never informed about fracking so the companies must be wanting to hide something”.

    I would suggest “integrity” should be kept out of your posts, Eliza, after the car crash from FOE on this very subject.

    So, it now appears it is suggested the discussion should be based on numbers of smiley faces?? (I watched a kid in a pharmacy recently press the smiley face button for service about 50 times whilst her parent watched with a silly grin.) Bet there were a few staff bonuses that week, but hardly meaningful.

    The same old, failed narrative. If you support the testing of shale gas extraction in the UK, you work for the PR companies or the shale gas industry.

    • [Edited by moderator]
      I had to smile when you suggested that Ineos ‘will have all the science on their side’. Jim Ratcliff, head of Ineos and one of the richest men in Britain, went on record (radio interview on the subject of shale fracking) as saying that “there haven’t been safety issues and environmental issues in America”. How could a man ultimately responsible for such a large company and with a huge vested interest in fracking (not to mention Grangemouth and its poor health and safety record) say such a thing. I don’t believe he is so unaware of the facts [edited by moderator].

  4. Amazing what the minds of some men will think up as a new method to extract resources from deep within the Earth and inject toxic chemicals and acids into the Earth and expect nothing harmful to happen…!
    how close will this type of drilling with acids be done to homes, schools, and farms….is there a minimum setback to homes, water wells, municipal water sources, natural waterways, etc..?
    The brilliant researchers can’t come up with a better method to create energy or harness energy for human use?
    We have our latest US Federal EPA Final Report on the dangers to water from hydraulic fracturing/ Fracking….that just came out about a month ago….check it out and see if you want to endanger you lovely England….
    And please don’t just trust your government, regulatory agencies, Industry….do you own research and find all the studies that the US folks
    have compiled: like the Compendium of hundreds of scientific, peer-reviewed studies showing the risks and harm of Fracking/Gas Drilling……:

    Wish you all well and may you not risk the populace for gain, profit, power like is being done in the good Ole, US of A…..

    • Thanks Vera – good to have your contribution from abroad. I’ve admired your brave work to expose the facts on fracking in your part of the world.

        • Thanks Vera. We’ve got heads of giant companies and would-be ‘scientists’ trying to tell us that there haven’t been any safety or environmental issues (with fracking) in the States and and that everyone is in favour of it. Would you believe it!

  5. The Ea are gung ho for putting any chemicals underground, or as one member of staff said at NYCC meeting, ”this is a fantastic opportunity to experiment and discover ……….’ note—discover–not deploy well established know how—just ”discover”’ I did want to ask him how much he got paid for saying that but couldn’t find him after the meeting…and he was young and so naive and probably wanted promotion in the new frack friendly EA org.

    I have consistently asked the EA which chemicals they are allowing in the chemical mix for frackers and they consistently fail to answer the question. They probably couldn’t care less or have a clue about the full nature and extent of the harm they are being told to go softly softly upon regulating.

    These are sad times for our health safety and welfare and yet again new potholes an sinkholes opening up in Ripon bringing down homes due to underground aquifers being erroded………………………..and ask your insurance company if you are insured against the impacts of fracking when it rolls out….

    You only have to walk the fells moors and mountains to see streams and ponds and rivers empty of all aquatic wildlife that inhabited it decades ago to see the result of acidification and industrialised chemical pollution now invading most waterways across the north of England. Fracking will add to this tenfold for generations to come as it will loosen up mercury, lead and other sleeping hazardous chemical pollutants many of which have yet to be identified and their dangerous effects understood.

  6. Do you have plans of the directions of proposed drilling? As one of your sites is near my home I’m worried about what you will be doing under it and potential risks to property structure, with the pumping of acids and extractions underneath.

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