Friday, 23 September 2011

Welcome to Frack-Land

So it begins......

If you haven't heard the news, after some exploratory drilling, Cuadrilla reckon that the shale gas reserves underneath Lancashire amount to approximately 200 trillion cubic feet. That's a lot of gas! Enough to fill 2 billion Olympic swimming pools (and x billion double decker buses and to cover y Waleses to a depth of z meters, etc etc etc). Put another way, and perhaps more importantly, at a price of $7 per 1000cbf (2007 prices, I don't have current prices to hand), that's $1.4 trillion dollars-worth of gas. Check out news articles here and here, for instance, or just about any other newspaper of your choice.

So what's this gas doing here? By which I mean - why didn't we drill and extract all of this gas at the same time as we were exploiting and developing the now-nearly-depleted North Sea reserves, back in the 70s and 80s? The reason is that under Lancashire the gas is trapped in shale rocks, rather than the sandstones that all oil industry geologists like. Because shales are made of tiny mud and clay particles, rather than nice round sand grains, they have very low permeability, making the process of sucking the gas through the rock to the well bore very challenging. Imagine trying to suck your drink through a straw filled with mud. Up until a few years ago, we couldn't do it.

However, a new technology has recently been developed to access this previously unexploitable gas. After a well is drilled, fluids (usually water, but sometimes CO2 or nitrogen gas) are pumped down and into the reservoir at high pressure. The effect of these high pressure fluids is to overcome the strength of the rock, causing it to fracture. The fractures in the rock provide corridors down which the gas can flow to get from the rocks to the well (and then eventually to our boilers and power stations).

The most likely reason you've found this blog is that you're already interested in fracking, (let's face it, it won't be for the humour, or Shakespearian-quality prose...) so you'll already be aware that this fracking process is controversial to say the least. There's the possibility of groundwater contamination from the chemical additives in the fracking fluid, there's the possibility of water contamination from methane rising from the reservoirs (cf. all the infamous flammable taps videos you'll find on youtube). And of course, there are those who feel, given that we already have enough fossil fuels at our disposable in known reserves to leave our planet considerabley warmer than nature intended, that we shouldn't be wasting time, money and effort exploiting and finding more hydrocarbons when we could be developing and encouraging greener, renewable options.

So it is on these issues that this blog will focus. I am an applied geophysicist-cum-geomechanical engineer, and I have some experience with monitoring fracking operations, so hopefully you'll find some informed opinions, ideas and facts on this blog. But I'm still not sure I have the answers to these questions. To frack or not to frack? That is the question. I intend to find out. On the way I hope to inform, engage and enlighten. And if I happen to amuse or entertain, I promise, it was entirely accidental....

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