Extended reach drilling

There are two key technologies that have enabled gas to be extracted economically from shales. Hydraulic fracturing is the technique that has garnered all of the attention. However, of equal importance is extended reach lateral drilling: turning the drill bit horizontally to drill sideways for several kilometers.

This technology was developed in the 1980/1990s - this graph shows the number of horizontal wells drilled in the US through the late 1980s to mid 1990s.

The number of horizontal wells has subsequently boomed, as the shale revolution has spread across the US - as the next figure shows for the Barnett:

  
Typical shale wells extend between 2 - 4 km in length. However, it is possible to go much further than this. Some of the longest "extended reach" laterals were drilled in the UK in the 1990s, allowing the operators of the Wytch Farm oil field to access reservoir compartments under Poole Harbour and the English Channel from their onshore drilling site.

The scale of these extended reach wells can be difficult to contextualise, but I'm going to try, using an image taken from Dr Ian West's incredibly comprehensive website (warning - for real geo-geeks only).

Dominating this cross-section is a profile of a Wytch Farm extended reach well. Staying topical (as ever), I will use the recent drilling at Barton Moss as a comparison. The extended reach well is over 10km long. If this well were being drilled at Barton Moss, outside of Manchester, then the toe of the well could reach Albert Square in the city centre. To represent this, I have added images of the Barton Moss drilling site and Albert Square to Ian West's image.

The well targets layers over 1.5km deep. This is equivalent to over 5 Shards, stood end on end. So I've also added a Shard, to scale, to the image.

Ian's image also compares the depths of various shale wells, including the rather shallow layer targeted at Balcombe, and deeper wells targeting the Bowland shale in the UK, and the Haynesville in the US. The Barton Moss well will also extend to 3km.

I don't have a particular point to make with this post, I just came across Ian's image while preparing an exam for Bristol's undergrads, and wanted to share how spectacular it is, when you consider the scales involved. Most shale wells in the UK will not extend to 10km. However, the Wytch Farm extended reach wells show what can be done, should the need arise in particular, difficult to reach areas.

Flares at Barton Moss

I will begin this post with a caveat - any movement or group will attract its fair share of idiots, with whom the majority of that movement would prefer not to be identified with. For example, there are plenty of people who seem to support shale development with whom I would prefer not to be associated.

Nevertheless, having in recent months experienced at first hand dishonesty from an anti-fracking protest group, this post seems necessary, although I am loathe to write it.

In recent weeks we have seen continued protest outside IGas's drilling site near Manchester. While this protest hasn't attracted quite the same amount of media attention as Balcombe did (perhaps the greater distance from London is a factor), the apparent firing of a flare gun at a police helicopter landing at Barton airfield did make many national news outlets.

The accusation prompted a rapid denial from the organisers of the protest camp. However, comments on blogs associated with the camp appear to paint a different picture (see the comments on this blog).
Again, another caveat - while these posts, apparently from protest camp members, seem genuine, there is no way of confirming this, so I would welcome any correction in this regard if required.

These posts appear to show that the protest organisers knew that a flare had been fired, and who had fired it, but that the negative publicity attracted by admitting this would have been too difficult to face, and therefore the decision for outright denial was taken instead.

The purpose of this post is not to criticise the main body of protestors. There will always be people willing to hijack genuine protests for more nefarious ends, and I can imagine that preventing this from happening is a very difficult challenge for organisers. It seems that they have acted swiftly in ejecting the flare-firer from their camp.

My particular concern, however, is the lack of honesty from the protest organisers. Rather than admit to an idiot, now ejected, in their ranks, they have chosen outright denial.

Both sides of the shale debate will of course always try to marshall the available evidence such that their position seems the more reasonable - this is the nature of debate over heated topics, particularly when further subjected to the polarising glare of the media. However, in this case the sheer chutzpah to issue a flat out denial, when knowing this not to be the case, shows in my opinion a rather concerning attitude to honesty.