Fluid migration, Legislation, Uncategorized, Well integrity

“Dear Aunty, will fracking fluid really contaminate our drinking water?”

Oh dear, goodness me, no that’s very unlikely cherubs.

Firstly, have a look at my earlier thoughts on well integrity and how it’s regulated.

Now then, sweeties, it’s important to think about how far below the water-bearing rock fracking actually takes place – the water table is typically around 600ft below ground whereas fracking happens at depths of over 5,000ft (see diagram below from DECC), which shows it at scale.

In between are lots of layers of rock. Some of these are permeable others impermeable.

Where the well passes through the water table, it is lined with at least three successive steel tubes (what our oil and gas friends call ‘casing’ sweeties). Between each of these, and between the outer tube and the sides of the whole, is cement. That’s at least 6 barriers my little loves.

Is it likely that all 6 of these barriers would be compromised at the same time, so badly that fracking fluid could escape? Not really cherubs.

So what about fluid escaping down at the very bottom of the well, where there’s usually only one steel tube and a single layer of cement protection?

Well, even in the unlikely event that fracturing fluid was to escape the well bore at this depth, darlings, it would somehow have to travel the thousands of feet up through all the layers of rock above. As some of you may have noted previously, water doesn’t tend to travel upwards under its own steam 😉 If it did though, during its upwards journey, any escaped fluid would pass through some layers of rock that are not just permeable but porous too and so any fluid coming into contact with them would actually diffuse into these surrounding rocks, delaying its travel and acting like a filter sweeties – in much the same way that mineral water is purified by traveling through rock.

For these reasons alone, my lovelies, it’s very unlikely that our drinking water will be compromised.

There are other reasons too, my little chick peas, but I’ll tell you all about them on another occassion.

Here’s one last thing to think about darlings: if contamination of water supplies is so prevalent, we’d see evidence of it in the areas that already play host to the 2,000+ existing onshore oil and gas wells – wells that have been built to the same standards, in compliance with the same regulations (BSOR and DCR), extracting oil and gas, and injecting fluids to stimulate the rock and increase/maintain reservoir pressure – but we don’t see this evidence because there is none. That’s not because the evidence hasn’t come to light, but because there haven’t been the subterranean escapes that many claim are not only a risk but a certainty.

They’re not, my dears.

Until next time…

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