In George Orwell’s 1984, the main protagonist, Winston Smith, works at the Ministry of Truth, or “Minitrue”, as an editor.
He is responsible for historical revisionism; he rewrites records and alters photographs to conform to the state’s ever-changing version of history itself.
In 2017 he might have got a job editing the new Backing Fracking website.
If he did we could probably expect output like this:
Terms like “fracture growth” and “fracture propagation” are used to describe the extent of the network of cracks that are created. The maximum vertical reach has been calculated as 350 metres from a horizontal well, but it’s important to understand that these cracks are random, won’t all form in a vertical plane, and are very narrow indeed – they are certainly not going to be “fissures.”
Fracking for shale gas in the UK will take place at very significant depths – typically more than 2,000 metres. Groundwater aquifers are encountered at about 180 metres below the surface and so you can see that even if fractures can “grow” upwards 350 metres, there will be 1,650 metres of separation between the two (that’s 5 times the height of the Shard in London, Britain’s tallest building) and virtually no chance of any connectivity occurring.
Like all good lies this content contains some truth, but it is subtly bent out of shape. This when we read “The maximum vertical reach has been calculated as 350 metres from a horizontal well” we should not take that as fact. In reality a study by the ReFine group at the University of Durham actually concluded that:
“Mathematical analysis of the datasets indicates that the likelihood of a natural hydraulic fracture extending vertically more than 350 metres is about 33 per cent. For hydraulic fractures stimulated by shale gas fracking, the likelihood of them extending more than 350 m is less than 1 per cent.”
That is not the same thing as a calculated maximum at all. Given the many thousand fracturing stages which will take place just within Cuadrilla’s licence area we can expect several hundred to exceed this height.
They are correct that Cuadrilla’s fracture plan suggests that fracking will take place at depths greater than 2,000 metres, but whoever put this together obviously doesn’t know much about the local geology. The suggestion that “Groundwater aquifers are encountered at about 180 metres below the surface and so you can see that even if fractures can “grow” upwards 350 metres, there will be 1,650 metres of separation between the two” seems to be based on the assumption that the Sherwood aquifer has no depth of its own, even if you ignore the obvious issue with forgetting about their initial 180 metres, as they do there.
In fact as the BGS tell us:
“The shallow aquifer is up to 40 m thick and is designated by the Environment Agency as a Secondary B aquifer. It is used for private drinking water supply, farms and golf course irrigation. In the area of the proposed shale–gas sites, this aquifer is underlain by a thick layer (up to 350 m) of a low–permeability mudstone, the Mercia Mudstone. Water moves slowly through this mudstone and it is not classed as an aquifer. Below this is the Sherwood Sandstone, which reaches a thickness of up to 750 m. The Sherwood Sandstone is classed by the Environment Agency as a Principal aquifer.”
So in fact the Sherwood Aquifer is not 180 metres below the surface but about 400 metres below it. The sandstone making up the Sherwood Aquifer is up to 750 metres thick, giving a depth of its lowest level at about 1150 metres not the 180 metres being suggested by our astro-turfing pals in their story above.
Assuming a fracture height of 350 metres that would, of course, still give a tolerance of 500 metres for fracking at 2000 metres. If the 350 metres quoted really were a maximum rather than just a probability this would be fine wouldn’t it? However, as the Refine paper tells us:
The maximum reported height of an upward propagating hydraulic fracture from several thousand fracturing operations in the Marcellus, Barnett, Woodford, Eagle Ford and Niobrara shale (USA) is ∼588 m
How much can we depend on this data?
Well Refine also state that:
Mathematical methods for estimating hydraulic fracturing height are simplistic (Fisher and Warpinski, 2011) and it is generally accepted that we cannot yet accurately predict fracture propagation behaviour in detail
So things wouldn’t seem to be quite so clear cut as our Backing Fracking chums would like to make out, as in fact the separation distance between the end of a fracture and the aquifer at Preston New Road might be nearer 250 metres than the 1650 metres claimed by them, and nobody is really sure if the 588 metres really is the maximum fracture height we should expect.
250 metres clearance for a fracture at 2000 metres, with an observed maximum fracture height (so far) of 588 metres, might still be a reasonable margin of course (if those mathematical prediction methods do turn out to be more reliable than ReFine suggest) , but this is rather less than 1 times the height of the Shard in London and about 7 times less than Backing Fracking’s “reassuring” maths is trying to tell us. Oops!
This begs the question why Backing Fracking are being so misleading. Is it incompetence or is it a wilful intention to exaggerate and misinform?
[And according to their own page , shouldn’t they be called “Backing Frac’ing” as they tell us the word “fracking” is “really known in the industry” as “frac’ing”. 😂]
PS – do we detect a little irascibility with Aunty in their closing “Fracking certainly isn’t the controversial technique that the BBC and others would like you to think it is.”? And we still think it is by the way.
PPS – it seems they follow everything we write here as shortly after I published this they put this sniffy Tweet on Twitter
(The inset is my reply LOL – 2 years ago they hadn’t banned me but when I didn’t post for a while they were telling each other they had. Then I argued a point with them and got banned properly. Oddly my life was not much diminished.)