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.

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.

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 http://royalsociety.org/policy/projects/shale-gas-extraction/report/), 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:

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".

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. 

Is Exxon's CEO a NIMBY?

Can you guess who is the latest star of the anti-fracking movement? No, it's not someone glued to something up at Barton Moss, but Rex Tillerson, CEO of Exxon. According to the Wall Street Journal, Tillerson has joined a lawsuit trying to prevent fracking in his local area. This would be something of a surprise, seeing as Exxon subsidiary XTO Energy is a major player in the US shale industry.

As you'd expect, the anti-fracking twittersphere has been set alight once more with this news. After all, if Exxon's CEO won't put up with fracking in his back yard, why should the rest of us?

However, is Mr Tillerson really against fracking? As so often seems to be the case, it pays to dig a little deeper. It seems that Mr Tillerson's opposition is not to shale gas extraction in his area, but to the construction of a large water tower next to his ranch. Moreover, while the water company involved has supplied water to fracking companies in the past, it has not done so since 2009: the primary use for the water tower is to supply residential demand.

Cuadrilla's new sites on the Fylde

The hot news this week is that Cuadrilla have announced two new drilling sites in Lancashire. Thus far, the drilling done by Cuadrilla, IGas, Viking and others has been exploratory, with the intention of taking core samples and well logs.

This represents the first time that company has announced plans to actually conduct hydraulic stimulations (i.e., "fracking") in shales since 2011, when Cuadrilla induced small earthquakes at their first Lancashire site.

This story has been all over the news, and there's not a lot I can add at this moment. The purpose of this blog is simply to draw attention to a rather neat little feature that Cuadrilla have created - interactive viewers that enable you to see what the site will look like before, during and after production. You can see these panoramics for Roseacre Wood and Preston New Road. I've done similar posts, using google street view to look at drilling sites in the US - both in Fort Worth and Los Angeles. Clearly the PR guys at Cuadrilla have been getting their ideas from FrackLand!

Perhaps the only thing missing from the Cuadrilla panoramics is the tent city for the protestors surrounding the site.

Statements from US State regulators on hydraulic fracturing

This post highlights a statement, made in 2009, from numerous state regulatory bodies pertaining to water contamination and hydraulic fracturing.

http://www.iogcc.state.ok.us/Websites/iogcc/Images/2009StateRegulatoryStatementsonHydraulic%20Fracturing.pdf

These various organisations quoted here represent the state regulatory bodies for oil and gas development. In the US it is the states, rather than federal organisations, that play the main role in regulation of this sector.

You'll note that in every case, no contamination is reported from hydraulic fracturing. How does this square with the numbers I reviewed a few weeks ago, where there are cases reported, albeit very rare ones?

The answer lies in how one defines hydraulic fracturing. To a well engineer, hydraulic fracturing refers to the process of pumping fluid down the well and into the reservoir, in order to fracture the rock. No more, no less. However, to the public, "fracking" has come to mean all stages of shale gas extraction, from drilling and casing a well, to the actual fracturing of the rocks, to the storage, transport and disposal of waste fluids.

Where we have seen contamination issues (and again, if you look at the AP numbers, rather than the headlines, these are rare) they are not due to the hydraulic fracturing process itself, but other aspects of the drilling process. For instance, we have seen issues with well casing leading to buildup of stray methane in shallow aquifers. We have seen examples where storage of waste fluids in open pits has lead to leakage at the surface, and we have seen examples of illegal dumping of untreated waste.

I think this distinction is important, which is why I usually talk about "shale gas development" or "extraction" when referring to the whole process chain, saving "hydraulic stimulation" or "fracking" to use them as they are defined from an engineering perspective.

The distinction matters when it comes to look at the risks that shale development might pose in the UK. We can see in the reports from the various regulatory bodies that the fracking process itself does not pose a risk. The issues appear to be: how the well is drilled and the casing is cemented; and how waste fluids are stored, treated and disposed of.

This is crucial, because it removes the major unknown in the process as an issue - that while wells in the UK have been hydraulically stimulated, current shale proposals represent a scaling up of the existing process. We have abundant experience in the UK of handling, treating, transporting and disposing of all sorts of chemicals, and the existing industry handles plenty of produced water every year.

Similarly, we've drilled thousands of wells both onshore and offshore, and we know how to address casing and integrity issues, which are rare to non-existent. It matters not to the near surface casing integrity whether a well is being used for "high volume" hydraulic fracturing, "traditional" hydraulic fracturing, acidization, or any other completion activity.

Part of the public's fear over shale gas is that it seems like a novel process, and we are scared by what we don't know or understand. In fact, the statements from the US regulators show that the unknown part (the "fracking") does not pose much of a risk - the riskier parts are in fact the parts that we know most about, and that we have the most experience in mitigating, regulating and minimising.