Monday, 31 March 2014

Image of the day: 2,000 onshore UK wells

Onshore drilling is not new to the UK. Approximately 2,000 wells have been drilled onshore in this country, mainly in the 1970s - 1990s. This map shows where they are, coloured by the year they were drilled (pre-1949 are cyan, 1950 - 1979 are yellow, 1980 - 1999 are (light) pink, and 2000 - 2013 are (dark) purple).

To download Google Earth .kml files for these locations, use the following links: pre-1949, 1950-1979, 1980-1999, 2000-present.

Friday, 28 March 2014

ReFINED well integrity

This week's big news was the release of the latest paper from Durham University's ReFINE Group (Research on Fracking IN Europe - academics love a dodgy acronym!). In it, they compile statistics on well integrity from a range of sources, as well as looking at well abandonment and orphaned wells (where the company owning a well goes bust, leaving a well with no-one to look after it).

This follows ReFINE papers on induced seismicity, and on hydraulic fracture height growth. Their approach in each of these cases is to use as much data as they can possibly get their hands on, with little thought for quality control, or on whether they are comparing apples with apples. In their own words:
This paper draws on a variety of datasets, mostly published, but in some instances sourced from online repositories or national databases, and follows the approach of Davies et al. (2013). In that study, the risk of induced seismicity due to hydraulic fracturing was reviewed, and intentionally included all datasets in the public domain that were considered to be reliable, rather than de-selecting any data (Davies et al., 2013). This inclusive approach has a drawback because well barrier and well integrity failure frequencies are probably specific to the geology, age of wells, and era of well construction (King and King, 2013). A wide range of failure statistics is therefore reported, and although they are presented on a single graph to show the spread of results, this is not intended to imply that direct comparisons between very different datasets (i.e. size, age of wells, geology) can be made.
This means that data from recent drilling in the Marcellus (which is probably relevant) is presented alongside less relevant data from offshore wells (drilling offshore is always a more challenging prospect, with hundreds of meters of water between your platform and the well-head), from China, or even from the 1920s in California.

Image of the day: First Frack!

This is a photo taken of the first hydraulic fracture stimulation operation, performed in Kansas in 1947 by Stanolind Oil.

Fracking has been around for many decades. However, it has evolved significantly during this time. In 1947, Stanolind used 1,000 gallons of napalm-thickend gasoline. Modern stimulations in shale reservoirs might use 1,000,000 gallons of "slick-water" - 99% water with chemical additives such as guar gum, polyacrylimide and hydrochloric acid.

Thursday, 27 March 2014

Guest Post: Frack Free Somerset Meeting, 22nd March

Dr Doug Robinson, now retired, but until recently a Senior Lecturer at Bristol University, attended a public meeting held by Frack Free Somerset last week. Following his visit, Dr Robinson contacted me to discuss the experience, and to outline his concerns about the group. His comments follow:
Notices posted by the frack free Somerset group for a meeting in Wookey Hole village about fracking “heading our way” attracted my attention being a retired geologist and local resident. I went along assuming it was a bona fide group raising rational concerns about unconventional gas recovery, and that there would be an opportunity to have an informed discussion on the pros and cons of the issues involved. At the introduction it was stated that the group had no political or other agenda and wanted to provide a balanced account of the pros and cons of the fracking controversy and that in the discussion, views and comment allied to both sides of the argument were welcome. 
The hour-long film produced by the group was said to present to provide a balanced and true view of the debate on unconventional gas development. The film, however, was largely based on opposition to the exploitation of unconventional gas, and of little more than a propaganda style repeating many of the unsubstantiated and well-known scare stories that have already been widely aired in the press and online. The film did use various cuts from interviews with professional Earth scientists, and also showed and gave quotes from the 2012 Royal Society report on “Shale gas extraction in the UK: a review of hydraulic fracturing” (available at, attempting to show engagement with scientific issues. These examples were however of negative points, and didn’t attempt to use such sources to present a scientific analysis of the process. Two examples can be used to demonstrate this point:

Wednesday, 26 March 2014

Image of the day: Hydraulic fracture height growth.

This figure is from a paper by Fisher and Warpinski (2012). The wiggles at the bottom show the maximum heights of hydraulic fractures, as imaged by microseismic data. The upper blue lines shows the maximum depths of drinking-water aquifers in the areas. 

This data shows clear separation of thousands of feet between drinking water sources and the rocks where hydraulic fracturing is being performed. This shows that hydraulic fracturing itself are extremely unlikely to be a cause of contamination - if water is impacted it is most likely to be from either spills at the surface or issues with wellbore integrity.


Image of the day: Induced seismicity in energy technologies

They say a picture paints a thousand words. Which can only be good news if you're a time-pressed academic such as myself. This post introduces a new feature - image of the day (or week or month, depending on how often I'm able to post.) Each time, I'll post a single image that will, hopefully, say a thousand words about unconventional gas extraction in the UK.

First up, an image from the 2013 Davies et al. paper on induced seismicity. The bar chart shows the magnitudes of earthquakes triggered by human activity in the subsurface. Many human activities can trigger earthquakes, including hydroelectric dam impoundment, geothermal energy, coal and mineral mining, waste fluid re-injection, conventional oil and gas reservoirs, and of course, hydraulic stimulation. These activities are represented by the different coloured blocks - hydraulic stimulation is the thin black boxes at M = 2 - 3 (2 earthquakes) and M = 3 - 4 (1 earthquake). You can see how this compares with other activities. In the words of Professor Davies himself at the Unconventional Gas Aberdeen conference this week, "in terms of earthquakes, shale gas doesn't even make it into the premier league".

Tuesday, 18 March 2014

Comments on the RSPB shale gas report

Today's post centers on a "new" report from the RSPB on the impacts of shale extraction in the UK. I say new, because it's really just a rehashing of a few existing reports (more on this below).

Before I get into the meat of things, there's one particular (not shale related) aspect I would like to address, because having been through it numerous times, and not always successfully, it is a subject very dear to my heart. The reports claims to be "peer reviewed" by the Center for Ecology and Hydrology. To my mind this is not a peer reviewed document. Peer review does not consist of handing your work to a friend to read over (though I would recommend to any young scientist that they do so BEFORE submitting for peer review).

Peer review implies an independent editorial body to oversee the process. Moreover, like the scientific process itself, peer review also implies the possibility of failure - that the reviewer has the option of saying that a paper is incorrect/unsuitable/makes unsupported conclusions and therefore should not be published. None of the above seems to be the case here, so I do not consider this report to be peer reviewed. That the authors are prepared to claim otherwise shows a worrying lack of respect for the process. Perhaps to non scientists this seems a little pedantic, but I'm sure anyone that has gone through the peer review process will understand that it should not be taken lightly, nor should the mantle of "peer-reviewed" be attached to things that are not.