New study shows leaky wells, not fracking, is causing methane leakage

This week's most newsworthy study examines methane contamination in wells in Pennsylvania and Texas, linking them with drilling activities. It is authored by the same Duke group who have published on this topic a number of times now.

In the new study, the authors analyse the geochemistry of methane and groundwater around shale gas wells. As well as measuring the geochemistry of the methane, they measure other geochemical variables such as noble gas isotope ratios and salinities, in order to get a better handle of what might be leading to the elevated methane levels.

They find that in some cases the evidence points to a deep source of methane that has migrated relatively rapidly, with little contact with the rock layers that lie in between shallow aquifers and the deep layers in which fracking is conducted. The most obvious conclusion to make is that methane is not getting into shallow layers through cracks and fractures in the rock, but that methane migration through faulty well bores to the surface is a possibility.

The study has, for obvious reasons, garnered a lot of publicity. However, the more I thought about it, the less newsworthy the study becomes. In actual fact, I think it tells us little that we didn't already know.

We already know that faulty cement and/or casing can allow methane migration from depth. We already know that in a handful of cases in Pennsylvania, poor working practice from certain operators has lead to cement/casing problems - these companies have been prosecuted and fined by the Pennsylvania Department of Environmental Protection. So it's hardly surprising that the authors of the study were able to find cases where the geochemical evidence pointed to this issue.

Another day, another shale gas report

Update (23.7.2014): It transpires that Gwen Harrison, the report's lead author, was recently an election candidate for the Green Party, which has explicitly stated its opposition to fracking in all circumstance. Moreover, judging by recent tweets it seemed she was involved blockading trucks at IGas's Barton Moss site.

Of course, there's nothing wrong with joining political parties nor joining protests. However, it makes a mockery of the claim that the report is "impartial" and "evidence-based", and goes a long way to explaining the report's contents.


Original Article:
Another day, another shale gas report to dissect. Today's offering comes to you courtesy of Scientists for Global Responsibility and the Chartered Institute of Environmental Health. The report claims to take an "impartial, evidence based approach". It does anything but, so once again it falls to me to point out the more egregious errors.

The best place to start is on the very first page, which shows two schematic images of the fracking process. In both cases the scale of images is such that the depth of the well is smaller than the height of the drilling rig, implying that fracking is taking place at a depth of less than 100m, rather than the actual depth, typically 2 - 3km.

Similar images are provided on page 4, and nowhere are images with the correct scales shown. The images are so out of scale that the "impartial, evidence based" claim immediately cannot be taken seriously. The moment you see an image like this, you know what to expect.

To the non-expert, the degree of the error in these images might not be immediately apparent, so I did a little photoshopping to demonstrate. Imagine if you were reading a report on whether it was safe for commercial airliners to overfly cities at altitude, and on the first page of the report was the following image, I don't think it would be taken that seriously by air safety experts:

Spotlight on SMEs: Ground Gas Solutions Ltd

In the first "Spotlight on SMEs" post, I showcase an SME (small/medium enterprise) that has already worked with Cuadrilla and IGas to assess the environmental impact of their sites.

Ground-Gas Solutions is an environmental monitoring consultancy that currently employs 15 people, although that number is expected to rise quickly in support of a growing shale sector. The main office is based in Manchester, but they have people working all around the UK. GGS specialise in monitoring ground and air pollution around industrial sites. GGS was founded in 2009 by Simon Talbot and John Naylor, who have previous experience in landfill monitoring and contaminated land investigation. 

While GGS serve a number of sectors, their services are already proving useful to shale gas operators. While environmental monitoring is not a new thing, GGS have developed novel sensors capable of monitoring the concentrations of potential pollutants like methane, hydrogen sulphide and volatile organic compounds (VOCs) continuously, rather than at discrete and irregular intervals. The image blow shows how a sensor is set up in a borehole to detect potential pollutants moving through the ground.

Image of the day: shale development and water stress

Several images this week. This images show "water risk" in the USA for a number of industries, as computed by the World Resources Institute. The more red the colour, the greater the water risk.

Firstly, oil and gas:

Followed by electricity generation:

 What about agriculture?

And the construction industry?

The food and beverage industries?

And the textile industries?

The conclusion? While shale gas does have the potential to use a lot of water, but the risk it poses is substantially smaller than many other existing industries.

Associated Press report on shale gas and pollution - what do the numbers really show?

The twittersphere has been alight in recent days with an Associated Press story examining records held by state regulatory agencies regarding complaints of water contamination related to drilling. This story has been widely reported across the media, generally with negative headlines, and extensively re-tweeted amongst anti-drilling campaign groups.

However, it pays to look beyond the headlines, to the actual numbers listed in the report, which is what this post will do. What does the AP report actually tell us about shale gas drilling and water contamination in 4 key US states?


The Question(s):

Firstly, however, it is important to state what we know, and do not know, and what we would like to find out. In scientifc terms, we must state our hypothesis. We already know that contamination can and has been caused at the surface by leakage of fluids from open waste storage pits (not allowed in the UK) and by illegal dumping of waste fluids into streams and rivers without treatment. We also know that contamination of groundwater by fugitive methane can and has been caused by faulty well cement and casing that allows deep sources of methane to move towards the surface.

The question we want to know is - are these types of incidents common or rare; and secondly, are they inevitable, or could they be prevented by better operating practice? If incidents are common and/or inevitable, shale development might be considered an inherently dangerous and therefore unacceptable process. If they are rare and can be mitigated by improved practices, shale gas development should be considered an acceptable technology.


The Data:

The AP report covers 4 states: Pennsylvania, Ohio, West Virginia and Texas. It does not specify in detail the nature of the complaints it discusses, which clouds the issue somewhat. However, from the report they appear to range from short term diminished water flow rates (not particularly serious), to contamination by stray methane migration (the most common complaint, apparently), to contamination by fracking fluid itself (the most serious allegation, I'd contend). Regardless, any incident or complaint is one too many, so for the purposes of this post they will all get lumped together.

If we are to determine whether these events are common or rare, we need to have data on the number of wells in the states considered by the report. The NRDC provides some figures for the number of oil and/or gas wells in each state, though these figures are from 2009, and don't say when the various wells would have been drilled, nor whether they are active or abandoned. However, the AP report doesn't specify whether complaints have originated from abandoned wells, old but still active conventional wells, or newly drilled shale wells, so perhaps the NRDC figures are the best to use. Regardless, I did a little more searching on various state regulator websites, finding the following:

• The NRDC list 47,000 wells in West Virgina in 2009. The West Virginia DEP website search function indicates a total of 2095 active gas wells, 96 oil wells and 33 CBM wells active from 2009 onwards (the 47,000 figure does seem high to me).
• The NRDC list 70,000 wells in Pennsylvania in 2009. From the Pennsylvania DEP website, a total of 32,625 new gas, oil and CMB wells were drilled (to "spud" in drilling parlance is to begin drilling) since 2005 (note the AP report incorrectly states there are only 5,000).
• The NRDC list 64,000 wells in Ohio in 2009. The Ohio DNR website lists over 50,000 active producing wells in 2011, although it appears that only 1,000 of these are target the Utica shale.
• The NRDC list 250,000 wells in Texas in 2009. The Texas Railroad Commission (who regulate oil and gas, obviously) count 17,000 wells in the Barnett shale in 2013, approximately 4,000 wells in the Eagle Ford shale (going by permits issued), and 800 in the Haynesville shale.

Before comparing numbers of pollution incidents with the number of wells, I first want to mention one striking feature of the numbers in the AP report - the difference between the numbers of complaints received, and the number of incidents actually substantiated though tests carried out by the various agencies. For Pennsylvania, in 2012 the DEP received 499 complaints, but substantiated only 5, meaning only 1% were considered valid. In West Virginia, the DEP received 112 complaints, of which 4 were substantiated (just under 4%). For Ohio, 113 complaints in 2011-2012, with 4 substantiated (just under 4% again), while in Texas none of the 62 complaints relating to water quality have been substantiated (so 0%). 

Why is the the percentage of substantiated claims so low? I'm sure some readers might be tempted to drag out the litigious American stereotype, ready to complain and sue anything and anyone at the drop of a hat. However, perhaps the most relevant data comes from Pennsylvania, where a Penn State study revealed that 40% of private drinking water wells are failing at least one environmental standard anyway. Furthermore, there are over 1 million drinking water wells in Pennsylvania, and approximately 20,000 new ones are drilled every year. 

The scale of these numbers shows why it is not surprising that many people might have complaints about their water quality. If there happens to be a hydrocarbon well near by, then with all the media coverage of fracking, it is inevitable that drillers get the blame. However, the 40% figure shows that there are in fact there are many other potential sources of contamination, and rigorous testing is required to determine where the blame should properly be apportioned. The AP figures suggest that in over 95% of cases, gas drilling is not to blame.  

Are contamination incidents common?

Lets move on now and consider the numbers of substantiated complaints with the number of wells drilled. For Pennsylvania, 106 cases out of 70,000 existing (NRDC) and 32,000 new (PA DEP) wells = 0.1%. For West Virgina, 4 cases, out of (using the low end DEP figures) 2224 wells = 0.1%. For Ohio, 6 cases out of 50,000 wells = 0.01%. For Texas, 0 cases out of 22,000 shale wells = 0%. For what it's worth, these figures are in line with other reports that have looked into this, such are this report by the Groundwater Protection Council, which reported incident rates per well of 0.01 to 0.03%. Our initial question was: are incidents common or rare? The AP numbers show that incidents of drilling-induced contamination are rare. 

Can better regulations reduce the impacts?

The second question was: is contamination due to drilling inevitable or can it be mitigated by better practice? The rarity of these events alone suggest that they represent aberrations rather than an inherent problem with the drilling and hydraulic fracturing processes. We can go further than this, however. During the Marcellus drilling boom in Pennsylvania, a number of new regulations regarding drilling safety and safe disposal of waste fluids have been enforced from 2010 onwards. Fortunately, for Pennsylvania the AP report breaks down the number of complaints by year, allowing us to judge the effects of these regulations.

The numbers of wells spudded in 2010, 2011, 2012 and 2013, respectively, was 3,340, 3,238, 2,374, and 2,175. In addition to the new wells, remember that opponents of drilling like to remind us that "all wells fail through time", so with all these wells coming in you'd expect to see the number of issues increasing through time, as problems emerge from both new wells and old. 

In fact, the numbers of substantiated issues (and the % of new wells this represents) are, from 2010 to 2013: 29 (0.86%), 18 (0.55%), 5 (0.2%) and 2 (0.1%). This represents a clear decrease in the number of contamination incidents as new regulations have come in to force. The AP numbers show that better regulation can reduce the impacts of shale gas drilling.

In Conclusion

To conclude, just as you should never judge a book by its cover, so you should be careful about judging a newspaper story by its headline. The numbers themselves in the AP report tell a very different story from the headlines it generated.

Shale gas life-cycle water consumption

Water consumption is not a subject that I have covered much on this blog. I've previously drawn attention to the amount of water needed for UK shale development in comparison to the amount lost by water utilities through leakage every day, but that's about it.

The facts and figures on the typical amounts needed to stimulate wells are well known to most by now, I'm sure (typically several thousand cubic meters per stimulation, and 5 to 20 stimulations per well). It has become de rigueur to make some sort of comparison with golf courses or other water intensive industries, but I think the most instructive information is to simply look at what proportion of total water  use is being taken up by shale developments.

Luckily, these sorts of studies have been done, and in Texas, home of the Barnett, Eagle Ford and Haynesville shales, shale development consumes less than 1% of total consumption in the state. It remains important that water withdrawals in particular areas are managed appropriately to avoid any local strains on water supplies, but less than 1% does not seem like an insurmountable issue.

This is not the end of the story, however. As with any new energy technology, we are not starting from scratch, so the relevant question is the comparison with existing processes. As we speak, my GridCarbon app (very useful, I highly recommend) tells me that we are getting 40% of our electricity from coal.

Therefore, if shale development is going to replace some of that coal-fired power, then the relevant question to ask is whether hydraulic stimulation for shale gas, before burning it in a gas turbine, uses more or less water than burning coal to generate electricity?

A recent paper has addressed this issue, looking specifically at the Texas situation, comparing life cycle water use between shale gas and coal fired power. Their numbers are slightly startling - water consumption per unit of electricity is between 25 to 50 times higher for coal-fired power than for that generated by shale gas.

I have copied the headline figure above, showing the net electricity generated in Texas from 1970, and the rates and volumes of water withdrawn and consumed in order to generate that power. Electricity generation has rise inexorably. However, from 2000 onwards, as shale gas has replaced coal, water withdrawals and consumption have reduced substantially.

I'll close with a link to one last paper (if you still have the energy) that again looks at this issue, and again the conclusion is that, with respect to water consumption, how the gas is produced is insignificant in comparison to the technology used to burn the gas in a power station, while using shale gas as a transportation fuel represents significant water savings over other transportation fuels.

Produced water disposal - a comparison with the conventional industry

A typical fracture stimulation stage requires approximately 1 million gallons of water. Depending on the specific site, you would expect between 25 - 75% of this fluid to return to the surface in the days following the frack. The fluid that comes back is called "flowback".

The injected fluid may contain about 1% chemical additive. The two principal additives tend to be friction reducers (which reduce the energy needed to pump the water) like polyacrimide (found in many cosmetic products) and thickeners (to help the fluid carry proppant) like guar gum (found in many food products). Cuadrilla have listed their ingredients here.

In addition, during its brief sojourn underground, the injected fluid can pick up additional material from the shale rock, including naturally occurring radioactive material (so-called NORM) and other minerals. Therefore, these fluids need to be treated before they can be safely returned to the water system.

The need to dispose of produced water is not a new problem for the oil industry. In most conventional hydrocarbon reservoirs, there is a certain amount of water trapped along with the oil. As the oil is produced, so is the water. As the field gets older, and most of the oil is gone, more and more water is produced alongside the remaining oil, and the "water cut" (the percentage of water produced alongside the oil) can be as high as 90% (i.e. 90% of the fluid produced from the reservoir is water, not oil).

As is the case with water injected for fracking, this water will have been in contact with the hydrocarbon reservoir, in this case for millions of years, rather than a few days. Therefore it may be highly saline, and it may contain NORM. This water, when produced, has to be dealt with.

A recurring theme in many of my posts is that what is proposed for UK shale extraction does not differ hugely from conventional operations, and also that we have a successful onshore industry with an excellent track record of minimising its environmental impact.

To make this point again, this time with respect to dealing with water produced from oil and gas wells, the table below lists the volumes of water (in barrels) produced from onshore UK oil and gas fields in 2012.

In total, over 73 million barrels of water are produced from onshore UK wells every year. The majority of this comes from the Wytch Farm oil field. Some of this water is re-injected into the reservoir to help force out more oil (approx 5 million barrels at Wytch Farm) but typically it is treated, and then, once clean it's discharged into the sea.

The larger UK offshore industry has to deal with an eye-watering (excuse the pun) 1.5 billion barrels of produced water every year!

A typical hydraulic fracture stimulation will use approximately 1 - 5,000 cubic meters (200,000 - 1,000,000 gallons) of water, or 6,000 - 30,000 barrels. Assuming that 50% returns to surface, that's 3,000 - 15,000 barrels of water to be processed for each frack stage.

This, again, is where comparisons with the conventional industry become pertinent - the current UK onshore industry has to deal with 73,000,000 barrels of produced water every year. It would take thousands of frack stages every year just to to match that rate. As an unnamed onshore operator commented to me recently (my emphases): "most people don't realise that all oil and gas wells produce water, more water than oil, and we have been dealing with it since way before shale gas. It is a lot of water. Can't blame the UK water on fracs!".

I'm not a chemist, so I'm not really up to speed with the details of how produced water is processed. I had an anonymous commenter on this post who seemed to really know his stuff. However, the best place to find out would be from the guys who are doing it, such as Lee Petts from Remsol, who has blogged about the issue here.  

Shale gas and "fracking": FAQ

What is shale gas?
Shale rocks are generally dense and black-coloured, formed from mud deposited at the bottom of past oceans, now solidified into rock. This mud is rich in un-decayed organic matter - that's what gives shales their black colour. When heated, the organic matter is transformed into oil and gas.

Once it has formed, some of this oil and gas is able to move out of the shale layers, rising through overlying strata, where it may become trapped in sandstone or limestone layers. This oil and gas is what we consider to be 'conventional' reservoirs, where we have usually looked for oil.

However, it has always been known that much of the oil and gas formed during burial remains behind, trapped in the shale layers. Compared to sandstones and limestones shales tend to have lower porosity, making it harder for the oil and gas to move about through the shale. This means that it is harder to extract gas from shale than from conventional reservoirs where the fluids can flow more freely.
 
So how is shale gas extracted?
Firstly, a well is sunk, which travels vertically through the overlying strata. When it reaches the shale layer, it turns sideways, drilling horizontally. Modern wells are capable of drilling over 10km horizontally: such wells are called 'extended reach laterals'. This part is absolutely no different to conventional drilling.

Once the horizontal well is drilled, it must be hydraulically stimulated, or as it has become known, "fracked". The horizontal well is "fracked" in portions, stage by stage every few hundred meters or so, meaning that a 2km lateral well might need 10 to 20 stages. For each stage, the targetted section of the well is sealed off, and water is pumped down at high pressure. This water will contain about 1% chemicals that make the stimulation more efficient: surfactants (basically like detergent) that make the water more 'slippery', so less pressure is needed to pump it; and viscosifiers, that help the water carry proppant (more on that in a moment).


The pressure of the water is sufficient to open up pre-existing fractures in the rock, and to create new ones. These fractures are important, because they provide a pathway for the gas to flow out of the shale rock and into the well. Above I pointed out that it is difficult for oil and gas to flow through shale rocks. It is the fractures that allow them to flow into the well. Towards the end of the stage, proppant is pumped with the water. Proppant is usually just sand and gravel, although ceramic beads can also be used. The proppant is pushed into the fractures that have been created, literally 'propping' them open, ensuring that the gas can continue to flow.

Each stage takes a few hours of pumping, so to "frack" all the stages of a lateral might take a week. Once that is completed, the well is ready for production. A small 'Christmas Tree' valve is placed on the top of the well, and the gas may continue to flow for years without any further intervention.

There's suddenly a lot of media fuss about fracking. It must be a new technology, right?
Wells were first hydraulically stimulated in the 1940s. It has been a standard tool in a driller's toolbox for a long time. Horizontal wells are in fact far newer, really only becoming common in the 1990s. Some would argue that the current developments have more to do with horizontal drilling than they do hydraulic stimulation. However, even with these developments, many geologists felt that it would never be possible to extract gas from shales at economic rates.

George Mitchell, a Texan, persevered through the 1990s, improving the technique, to show that it was in fact possible, and the shale revolution was born. Since then, a drilling boom exploded as American companies realised they didn't have to look abroad, or in the deep and treacherous waters of the Gulf of Mexico, because huge volumes of oil and gas were to be found under Texas, Colorado, Pennsylvania and now 30 other US states.

So hydraulic stimulation, or "fracking", is a very well established technique. Horizontal drilling, just as essential to shale development, but much less talked about, is newer, developing in the 1990s.

However, to extract gas from shales requires more fractures than in a conventional reservoir, as they are initially less permeable. Therefore, the volumes of water being injected for shale are typically larger than that used previously in conventional reservoirs. So while current developments are not using new technology, it does represent a scaling up of that technology.

I've heard about scary-sounding chemicals contaminating water supplies. Is this true?
Opponents of fracking sometimes talk about the 500 toxic chemicals needed to "frack". I don't think any stimulation needs 500 different chemicals: that's probably the total number used in the history of the technique, not the number used for a single stimulation.

The two main chemicals used are surfactants (found in most soaps/detergents) and viscosifiers (typically guar gum, used in many food products). While not hideously toxic, I wouldn't want to drink water contaminated with surfactants and the like (who'd want to drink the sink-water after they've done the washing up). In addition, the water injected during "fracking" comes into contact with the deep shale rocks. These sometimes contain heavy metals and salts, which may also enter into the "fracking" fluid.

The most obvious way for these chemicals to enter groundwater is if they are spilled on the surface. There is an example from Louisiana where 17 cattle died after undiluted KCl was allowed to spill off of a drill pad. Many of the reported issues in the US are due to the ponds used to hold the waste fluids: open pools lined with plastic. The lining of these ponds has been known to tear, or if it rains heavily they can overflow. Ponds like this are not allowed in the UK for exactly these reasons. In the UK waste fluids must be stored in double-lined steel tanks: this is a major difference between drilling in the UK and the USA.

Safe management of fluids on the surface should be standard practice for all oil and gas operations - you can read here all the precautions Cuadrilla have taken at Balcombe, layer upon layer of protection to ensure that no substance on the drill site is allowed to leak.

The secondary concern, of course, is what happens when the fluid is injected into the ground. "Fracking" takes place well below the water table, typically at depths of 2 - 4km (most potable ground water is found within a few hundred meters of the surface). So there is a lot of solid rock between where the fluid is injected and any potable water.

For the injected fluids to contaminate groundwater, two things are required: (1) a path (such as faults and fractures) along which these fluids could migrate, and (2) a force to push these fluids along this path.

If there were an easy path allowing fluids to move upwards, then the oil or gas, more buoyant and more mobile than water-based "frack" fluids, would have already travelled through these paths during the 200 million years of geologic history for which the gas has been trapped. Therefore, the fact that the gas is still trapped there to start with tells us that such paths are unlikely.

As for a driving force to push the fluids along such a pathway, should it exist? The water-based "frack" fluids, with their various additives, are of a similar density, or perhaps even more dense, than the brines that fill non-gas-bearing rocks at these depths, and of course much denser than oil and gas. Therefore, they will tend to sink downwards, rather than rise upwards. There is no driving force to push the "frack" fluids back towards the surface.

So we have no pathway, and no driving mechanism, to cause injected "frack" fluids to rise upwards towards potable groundwater sources. This was the conclusion of a recent study into the possibility of hydraulic communication between shale layers are depth and shallow groundwater bodies, finding it "physically implausible".

That's all fine in theory, what about the evidence? Well, a number of studies have been done on water quality in shale areas. Only one, a recent paper by an Arlington group has suggested any kind of link between drilling and contamination by "chemicals". They found a correlation between arsenic and selenium levels and proximity to natural gas wells. They are uncertain in their conclusions, however, as there are a number of possible causes for their observations. Moreover, they do not link their observations with any communication of "fracking" fluids from depth - if drilling is to blame, they believe is likely to be due to vibrations from drilling operations that agitate old, rusty water wells. This agitation of old rusty metal is the most likely source of the observed metals.  

The majority of water quality studies have found no evidence of fracking-related chemicals in groundwater: some (one from the Duke team, one by Molofsky et al) found no evidence of any effect whatsoever on water quality. One from the Duke team found evidence for methane contamination (see below), but no evidence for "fracking" fluids.

I've also seen videos of a tap catching on fire? Is methane leakage a problem?
Perhaps the most dramatic footage in the famous Gaslands film is the scene where the farmer can set his tap water on fire. This is caused by methane gas contaminating groundwater. Methane itself is not toxic in any way, although if it builds up in large enough quantities it presents a fire hazard.

There are two potential ways that methane trapped at depth in shale rock could get into shallow groundwater - through a pathway in the rock, or through a gas well. As above, if there were an existing pathway through the rock to the surface, then the gas would have already taken that route during the millions of years that it was otherwise trapped. Unlike "fracking" fluids, methane is buoyant and mobile. In drilling a well, a new potential pathway is created for methane to get to the surface.

When wells are drilled, they are lined with several concentric layers of steel, called the casing. When all is as it should be, the gas flows up the middle of the well, inside the casing, to the surface. The casing is fixed into place with a layer of cement that fills the small gap between the casing and the rock.

If there are gaps or cracks in this cement then methane can move up through this gap (sometimes called the annulus) towards the surface. Of course, the crack/gap has to run all the way from the shale layer to the surface. Well bore integrity has long been known as a potential problem for all oil and gas wells, for both conventional and shale reservoirs.

There have been definite examples where poor casing/cement has lead to methane migration into shallow groundwater. Dimock, Pennsylvania, is probably the best-known. The company involved was cited for a number of violations of drilling regulations, and fined heavily. The wells have since been repaired, and methane levels have fallen back to below safe minima. Casing and cement is something the industry has been working with for a long time - there are monitoring tools that can be used to check that there are no gaps or cracks in the cement, and, as at Dimock, it is possible to repair problematic casing.

The majority of methane-in-groundwater complaints come from Pennsylvania. This perhaps inevitable, because methane occurs very commonly in groundwater in PA. There are a number of natural ways that can lead to methane in groundwater. Of course, that means that determining when gas drilling is to blame, and when it is natural, can be problematic.

We know at Dimock the gas was drilling-related. But how common is this problem. There have been three main studies here, two by the Duke team, one by Molofsky et al.. The Duke team studied the Fayetteville shale, Arkansas, and did not find any evidence for drilling-induced methane contamination.

However, when they examined the Marcellus (Pennsylvania), they found evidence for drilling-induced methane contamination. Yet this paper has come in for substantial criticism for two main reasons: the number of samples analysed (only 160ish), and the apparent non-randomness of where the samples were taken from.

To address this, Molofsky et al conducted a much wider sampling regime (over 2,000 samples). They found that if you lived near a gas well, there was a 3 - 4% chance of finding methane in your groundwater. However, if you lived in an area with no drilling, there was also 3-4% chance of finding methane in your groundwater. When you look regionally, whether or not you are in a drilling area doesn't appear to affect the probability of groundwater methane occurrence.

What can we conclude from this? Well integrity and methane leakage is an important issue for the industry, one that it needs to keep on top of. We've seen at Dimock that if a company takes shortcuts, and violates regulations, this can be an issue. Importantly, there are ways to check cement integrity once a well has been drilled, and ways to repair problems.

The question is, how widespread is this issue? The data from Molofsky et al appear to show that it is likely to be a few isolated incidents, rather than a widespread problem. Reviews by the US Groundwater Protection Council have come to a similar conclusion.

I've heard that 5% of wells fail immediately, and that 50% fail eventually?
This is a statistic often cited by opponents of drilling looking to highlight the methane leakage issue discussed above. The statistic comes from a paper by Schlumberger examining wells in the deep Gulf of Mexico, and particularly the chart on page 2. Firstly, it's worth noting that this 'paper' is basically an advert by a company selling well repair solutions, so it's in their interest to 'big-up' the stats as much as possible.

More importantly, what do we mean by 'well failure'? In the context of shale gas extraction, we surely mean that a well that is allowing methane to leak into shallow groundwater. This is where the use of the above statistic is somewhat disingenuous. The statistics in the paper are for sustained casing pressure, or SCP. This is where a portion of the annulus remains pressurised when it shouldn't be. This is absolutely not the same as a well leaking - leaking well will probably experience SCP, but that doesn't mean that SCP indicates a leaking well.

Equally disingenuous is the fact that these stats come from deepwater Gulf of Mexico wells. Drilling is a lot more challenging when there is a couple of kilometers of water between your rig and the ground (as the Deepwater Horizon accident showed). It's only in recent years that drilling technology has advanced to enable us to drill there at all.

It's not a fair comparison to link wells drilled in the GoM with onshore shale wells, the drilling and casing of which is no different to the thousands of conventional onshore wells we've been drilling for almost a century. It'd be like using the number of crashes in an F1 race to predict how many accidents there'll be on the M25. Deepwater GoM wells are at the limits of our technology. Shale gas wells are far more mundane.

If we really want to understand how common well casing issues might be in the UK, surely the best place to look is at our many current onshore wells. There have been over 2,000 wells drilled onshore UK. Whether on not they are "fracked" or not has little bearing on casing integrity. These 2,000 existing onshore wells will be no different to shale gas wells. I'm not aware of any complaints of casing integrity issues or methane contamination from any of these existing sites.

Didn't fracking also trigger an earthquake in Lancashire. Is that common?
It did. In 2011, when Cuadrilla "fracked" a well near Blackpool, two small earthquakes were triggered. Both were very small, at the limits of what humans can feel, and would have caused a similar amount of shaking to an HGV driving past your house.

It's a fact not often appreciated that everything we do in the subsurface carries a small risk of triggering an earthquake, whether it be coal mining, conventional oil/gas, geothermal, hydroelectric. Even quarry blasts are basically man-made earthquakes. Shale gas is no different, there will always be a small risk of triggering small earthquakes. However, this risk is small: only one of the hundreds of thousands of "frack" stages in the US has triggered an earthquake. Any quakes produced will be too small to cause actual damage. DECC have said that every future "fracking" site will require seismic monitoring, and Bristol University have currently deployed seismometers at the Balcombe site (even though they're not planning to "frack" at this stage).

I know that some forms of hydrocarbon extraction lead to subsidence issues. Could that be a problem for shale gas?
When you remove material from the ground, a space is created that is sometimes filled by the overlying material subsiding into the gap. This is particularly true for coal mining, which can cause severe subsidence.

However, shale rocks are dense, with low porosity. That is why they need to be "fracked" to get the gas out. Because of this, they are usually mechanically strong enough to support themselves once the gas is removed. As such, subsidence is not expected to be an issue during shale gas extraction. The Barnett shale in Texas is the oldest shale field: production started over 10 years ago. There has been no measurable subsidence during this time.

How much water will be needed?
Several million gallons of water, or 2 - 5,000 cubic meters of water are needed for each well. That's a couple of olympic-sized swimming pools. That sounds like a lot of water. However, it's important to keep that number in context. The average golf course can easily use this much water a week in summer months. Similarly (and a lot more shockingly), UK water systems leak over 3 billion liters (3 million cubic meters) per day. So if we our utilities were to improve leakage by 1%, we'd have enough water to "frack" 30 stages every day.

In all but the driest places, shale gas development doesn't pose a strain on water resources. Moreover, water abstraction is regulated in the UK. If demands on water resources are too great, the Environment Agency will not provide a license to abstract water, and utilities will not provide it.

What about air pollution, is that a potential issue?
Along with water contamination, this is one of the hot issues for shale extraction, because it involves people's health. There have been a number of regional-scale air quality surveys that do not find any evidence for drilling-related air quality issues, including in the Barnett shale and in Pennsylvania. In fact, the Pennsylvania report shows significant improvements in air quality, mainly because coal-fired power stations are being replace by gas power stations.

More localised studies have found the occasional issue, mainly it seems with compressor stations rather than drilling sites. However, even these studies have concluded that "the screening results do not indicate a potential for major air-related health issues associated with the Marcellus Shale drilling activities".

Fracking might be ok in the wide-open spaces of the US, but surely there's no space for it in the UK?
It's true that shale gas extraction is easier in unpopulated areas. Opponents of shale gas often show images of the Jonah gas field, where the land is covered with wells. This is actually a conventional gas field, drilled in the 1990s, before horizontal drilling had taken off. The benefit of horizontal drilling is that you don't need nearly as many well pads.

The truth is that the drilling industry is very adaptable. Sure, if you give them a big empty space and tell them you can drill all over it, then they probably will. However, they can cope in far more constrained conditions when it is necessary. Perhaps the best example of this is Dallas-Forth Worth. This is the 9th most populated city in America, with a population of over 6 million. Yet the Barnett shale runs right underneath, and it's being drilled. By using long lateral wells, drilling sites can be squeezed into urban and suburban areas without taking up much space at all.

Does the UK have much of a record for onshore drilling?
The UK onshore industry does not have a very visible profile. However, it is there: we produce 100 million cubic meters of gas per year. Over 2,000 onshore wells have been drilled in the UK. Of these, about 200 have been "fracked". I've plotted a map of all the wells here. In some places, such as Beckingham Marshes, they manage to squeeze a lot of wells into not-very-much space, without upsetting local people.

The UK onshore industry has been very good at staying out of sight, and very good at making sure they do not pollute. If we want to predict what shale gas development in the UK will be like, the first place to look should be the current onshore industry, which does a very effective job working with local communities.

I've heard that the methane leaks mean that shale gas is actually worse for climate change than coal. Is that true?
Burning coal for electricity produces approximately 3 times as much CO2 as natural gas does. Therefore, switching from coal fired to natural gas fired electricity should represent a significant benefit. CO2 emissions in the US have dropped significantly as gas has replaced coal as a source of electricity.

However, natural gas production has the potential to release methane to the atmosphere. Methane is also a potent greenhouse gas, so if shale gas extraction emits a lot of methane, it could counteract the benefits of reduced CO2. This was the premise of a paper by Howarth et al., which has garnered a lot of publicity. However, this paper has come in for a raft of criticism, as most other studies on the subject have indicated very clear benefits from switching from coal to gas. No Hot Air lists some of the scathing comments about the Howarth paper.

A study funded by the EU Commission concluded that, with respect to greenhouse gas emission, domestic shale gas production has a similar footprint to imported gas (that has to be compressed and shipped to Europe from the Middle East), and a significantly better footprint than coal. 


Even if it's better than coal, gas is still a fossil fuel. Surely we should be focusing all our efforts on renewable electricity?  
Now we're on to a more serious criticism of shale gas development. We know we already have more fossil fuel reserves than we can safely burn without causing catastrophic climate change, so why are we bothering to look for more?

My answer to this comes in two parts: firstly is to point out, as above, that for a unit of energy produced, shale gas emits less than half as much CO2 as coal. If we are to avoid climate change, there must presumably be an upper limit to the rate that we can emit CO2. If the treat of climate change requires us to ration our CO2 emissions, it seems obvious that we should choose the fuel source that gives us the most energy for that ration of CO2 emission. That fuel source, by a significant margin, is gas.

It's correct that we should leave a large portion of our current fossil fuel reserves in the ground. That portion, however, should be coal. Moreover, renewable energy currently requires flexible backup sources - an abundance of gas provides this.

My second argument relates to how we get to a point where our CO2 emissions are reduced. A common call is that 'we should be investing in renewable energy sources'. This is absolutely true. However, in order to invest, you need to have money to invest. Given our current economic struggles, it becomes harder and harder to politically justify renewable energy receiving public money, either as a supplement on bills or as a direct subsidy from the treasury.

If the economy improves, there will be more money available to invest. In my opinion, we should be ring-fencing a proportion of the taxes made on shale gas development, in order that they be re-invested into renewables and/or next-gen nuclear. This would ensure that in the short term we reduce our CO2 emissions by replacing coal fired power, but that in the long term investment continues in alternative energy sources, such that they will be ready as soon as possible.

That's the theory, how does this bear up to reality? Well, Texas is the undisputed home of shale gas, with the Barnett, Eagleford and Haynesville shale plays. Yet, perhaps surprisingly, Texas is also one of the leading states in terms of renewable energy, and the renewables boom has occurred at pretty-much the same time as the shale boom. In Texas, at least, a booming shale gas industry has gone hand-in-hand with booming renewables, rather than competing with each other.

Will shale gas have an impact on my gas bills? 
This is somewhat uncertain, and as a geoscientist I'm probably straying outside of my main area of expertise. The most recent report commissioned by the government suggests prices could fall by 25%. However, other reports have suggested it would have less of an impact.

However, it's important to look at the economic impacts beyond consumer gas prices. At present, we expect to be buying more and more gas from places like Norway and Qatar. That is money that leaves the UK economy for good, never to be seen again. It creates no jobs, and pays no taxes.

In contrast, a UK shale gas industry would provide jobs for UK workers. It's true that some of those jobs would be specialists, attracting high-payed international workers. That is still beneficial to the UK economy, because those people will live in the UK, and spend their money here. But there are many lower-skilled jobs involved as well.

Moreover, remember the manufacturing chain. For example, well pads need cement. The casing is high quality steel, and each well needs several kilometers of it. That means work for people who make cement and steel. Add in the mulitplier effect, as more employment means more people buying things in shops, eating in restaurants, staying in hotels, and it's clear that, whatever the effect on the gas price, shale development will have a significant impact on the economy.

Equally, any gas produced will be taxed. That's money going into the public purse, to be spent on schools, hospitals, or even wind farms. Public finances appear to be somewhat short of cash at the moment. Given our current situation, I don't think we can afford to be handing billions of pounds a year over to Qatar to host an air-conditioned World Cup when we could be reaping the economic benefits of shale gas development at home.  


 

Guardian given lifelong ban on talking sense

In the latest Guardian shale shock story, a shale gas company in Pennsylvania (Range Resources) stands accused of poisoning a family's water (the Hallowiches), then imposing a court gagging order to silence the family, including the children, from ever talking publicly about fracking ever again.

In actual fact, this story has been 'out' in the US for quite some time, so it's hardly the scoop that the Guardian are claiming. More importantly, however, are the numerous facts left out in the name of a good scare story.

Court gagging orders are never going to make for good PR, but the key question must be: did Range Resources actually cause contamination of the Hallowich water supplies or air quality? Everything else is just lawyers throwing their weight around.

Pennsylvania DEP conducted an investigation into the Hallowich groundwater, and their findings are available. Here are their conclusions, which I shall selectively quote from below:

you allege that Range Resources has contaminated the supply [...] After a review of the information, including primarily water analyses, we cannot affirm your conclusions.

Importantly, Range actually drilled their well in July 2007. The Hallowiches only purchased the property in June 2007, and didn't drill their water well until October 2007, 3 months after the shale well was drilled. Therefore they can have no evidence regarding water quality prior to shale drilling.

Acrylonitrile and styrene appear to have been identified as an offending chemicals. However,

RT’s [a water testing lab] own sampling did not measure any styrene at the reported detection level. How styrene might be related to gas well drilling is not clear. However, the water lines in the Hallowich household, as well as from the water well to the house, are PVC which contains styrene.

and

Acrylonitrile is used in the manufacture of plastics, glues, pesticides, ABS pipe (common drain line pipe used in homes; the “A” in ABS stands for acrylonitrile ), synthetic rubber, acrylics, carpets, dinnerware, food containers, toys, luggage, automotive parts, appliance, telephones, among others. It can also be washed from the air by rain and then enter the groundwater system. There is a plastic rock which has been placed over the water well and could be leaching contaminants into the ground during rainfall events, which interestingly enough is when Mrs. Hallowich reports that the acrylonitrile values seem to increase based upon on-going sampling that apparently has been occurring.

This might be why, in the absence of any data prior to drilling, the DEP tested water from nearby wells close to the shale drilling, and did not find acrylonitrile or styrene:

the results taken at a neighboring property (163 Avella Road), which is also close to the gas well, only shows a lead problem; the other four parameters are either non-detect or within drinking water standards. 

In conclusion, the DEP summarise:

Mrs. Hallowich alleges that the drilling of the gas well polluted the aquifer. [...] we are lacking any direct evidence to prove this assertion.

we question your conclusions about the contamination problems to the Hallowich water supply. The only parameter that is clearly above the MCL is manganese, and we cannot clearly link it to the drilling of the Range Resources gas well. Therefore the DEP cannot issue a water supply replacement/restoration order to Range Resources.

This area also formed part of a DEP study into air quality impacts of Marcellus drilling, similarly finding that

the screening results found during the five-week study did not indicate a potential for major air-related health issues associated with the Marcellus Shale natural gas activities

Given the above data, it is perhaps not surprising to find that, in the court documents, the Hallowiches concede that:

1. With respect to Plaintiff minors’ alleged claims involve nuisance and personal injury claims, there is presently no medical evidence that these symptoms are definitively related to any exposure to the activities of Defendants...

2. The minors have alleged claims for nuisance and personal injury in connection with Defendants’ business operations.  There is presently no medical evidence supporting that these claims related to any exposure to Defendants’ business operations as set forth in Plaintiffs’ Complaint.

When the court order to 'un-gag' these documents were made, there was much excitement in the media in the hope that a smoking gun was about to be revealed. Much has been made about such gagging orders: surely now the release of one such set of documents would catch the frackers red-handed. Instead, they found instead that once again, water and air testing by the relevant government agencies had failed to find evidence of fracking-induced contamination:

There's no doubt that gagging clauses make for bad PR. However, this case shows that just because they have been used, doesn't mean that there is evidence for shale gas pollution. In fact, as the Pittsburgh-Tribune has the headline, it might be better to describe the situation as: Couple collect $750K settlement in fracking case with no medical evidence.

The information I've presented above is easily-locatable in the public domain. Which begs the question - why does none of it make it into the Guardian's latest scare story? I think we're all fine with media organisations that take a well established editorial line - it's unlikely the Guardian are ever going to favour shale gas extraction. However, I'm a lot less happy with irresponsible scare-mongering, which is what I see this to be.

More studies on groundwater methane in Pennsylvania - no correlation with gas wells

Warning: High concentrations of methane in water wells, well enclosures and other confined spaces can cause explosions!

Here's a fact sheet from the Pennsylvania Dept of Environmental Protection providing information about how to deal with methane in your water well (it needs to be vented so that dangerous accumulations do not build up).

Have the DEP been forced to release this emergency information in response to increases in methane contamination as shale gas drilling spreads across the land?

No, in fact if you look closely in the bottom right corner, you can see that this information sheet was published in January 2004: long before shale gas came to Pennsylvania. This provides further demonstration of elevated methane in groundwater was common prior to drilling, as has already been indicated in baseline studies.

Why does this matter? Well, in a previous post I discussed the recent Duke findings of elevated methane in water near to gas wells in Pennsylvania, and I suggested that the very non-random way in which wells were chosen for sampling may well affect some of their conclusions. I suggested that to test their conclusions, more uniform and comprehensive sampling would be required.

Well, in a recent paper published in Groundwater, we have some new data. Molofsky et al tested 1701 samples (as opposed to only 141 tested by the Duke team). The two pictures below show the sampling from Molofsky (above) and the Duke paper (below), I leave it to you to judge which provides the more comprehensive sampling:

 

Of the 1701 samples tested by Molofsky, 322 were within 1km of a gas well, while 1379 are characterised as being 'pre-drill' - that is no gas well within 1km at the time of sampling, taken as part of a baseline surveys conducted by the DEP.

Molofsky et al found that 78% of sampled wells had detectable methane concentrations (hence the need for the DEP's fact sheet above), and 3.4% had levels exceeding the DEP's minimum level of 7mg/L.

The size of the circles in the Molofsky figure represent the amount of methane found in groundwater. They've helpfully plotted topography in their figure - even without the help of statistics you can see a correlation with being in a valley and having elevated methane (although the stats bear this correlation out), and upland areas with low methane. Why would being in a valley lead to elevated concentrations of naturally occurring methane? Well, a picture (from a Molofsky presentation I found online) tells a thousand words:

What about correlations between methane and natural gas wells, as found by the Duke study? Well, with 10 times as many data points, Molofsky et al find zero correlation between methane and natural gas wells. As their subsection title puts it: 'No Regional Association of Methane with Gas Production'.

Methane found around gas wells in PA. Methane also found not around PA gas wells....

Two more studies looking at the connection between shale gas extraction and water contamination have been released. One from the USGS, looking at water quality in areas of Pennsylvania that haven't yet been drilled, and one from the same Duke team that has in the past found evidence for drilling-related methane in groundwater in Pennsylvania, but did not find evidence for any contamination above the Fayetteville shale (in Arkansas).

The USGS study examined water quality in Sullivan County, Pennsylvania. Crucially, this study focussed on areas that have yet to be drilled for shale gas. So far in the USA such baseline studies have been rare, which means that it can be difficult to establish whether water has been contaminated by shale gas drilling, or whether it was already of poor quality to begin with.

As I have discussed in a prior post, it is wrong to assume that all groundwater was of Evian-quality prior to drilling: there are many potential sources of groundwater contamination, both natural and man made, that could have caused problems well before shale gas drilling began.

Therefore, although this USGS study hasn't received the press attention given to the Duke study, it could come to be seen as really important, because it provides a baseline against which changes caused by drilling can be assessed.

So what does the Sullivan County baseline look like? Well 85% of the 20 water samples taken contained at least some radon-222 above the US maximum level of 300 picocuries per liter (pCi/L), while 10% exceeded the alternate maximum level (I have no idea why the USEPA has a maximum level and then an alternate maximum level - what does that mean?) of 4,000 pCi/L. 35% of the wells had some methane in them, although only 2 samples (10%) had levels to get excited about: 4.1 and 51.1mg/L (the US maximum level is 10-28mg/L).

Importantly, the USGS carried out isotopic fingerprinting of the methane in these wells. It is possible to tell the difference between methane that has been created in the shallow surface by bacterial activity (so-called 'biogenic' methane) and that created at depth by heat and pressure (so-called 'thermogenic' methane), and it has been suggested that, where thermogenic gas is found, shale gas drilling is the likely culprit.

Unfortunately, the isotopic fingerprinting of the Sullivan County gas showed that is WAS thermogenic, in an area WTHOUT any gas drilling. Does this mean that the thermogenic/biogenic testing can no longer be used as the determining factor in the debate over whether methane is caused by shale gas extraction? I think at the least more caution might be required.

The main take-home point from the USGS study is that water quality in the region is highly variable. This means that, whether you believe that shale gas drilling has or has not caused contamination, proving your case either way will be very difficult, especially without baseline studies.


Moving on to the Duke study, which examined the water quality in gas-producing areas of Pennsylvania. Rather than bore you with statistical analyses about P<0.0007 for this and P=0.0001 for that (necessary for science, less interesting for blogs), I think the story would be better told with a couple of pictures. Firstly, where the groundwater was sampled (along with the locations of shale gas drilling):

and then the results - methane concentration plotted versus distance from shale gas wells:

There appears to be a clear correlation with increased methane concentrations near to gas wells.

The Duke researchers also looked at the isotopic composition of the methane gas, finding it to be thermogenic, and they also found ethane (a slightly heavier form of natural gas, not produced biogenically), implying that the gas must have originated at depth, and therefore be caused by shale gas drilling. I think that this part of their conclusions is slightly shakier - we've seen from the USGS study above that it is possible to have thermogenic methane, and smaller amounts of ethane, in areas that haven't seen drilling.

I also have some doubts about how the wells were chosen for analysis. You can see from the first plot that the wells sampled occur in clusters - they're very non-random. Above I pretended to chose not to discuss the statistics in the Duke paper to save the poor reader from a load of boring numbers. In fact, my concern is that such statistical analyses usually assume a certain degree of uniformity in a sampling process, and that doesn't seem to be the case here, so I'm not sure as to their validity.

In the methods section of their paper, the Duke team mention that they got their samples via Homeowner Associations. Although which homeowner associations these might be are not described, it seems likely that these are homeowner associations would be those opposed to natural gas drilling. In turn, such associations are presumably likely to have (a) elevated methane concentrations in the water and (b) gas drilling in the near vicinity. So, if your sampling is biased by choosing to select water from sites that match both descriptions, it's not particularly surprising to find homes near gas wells with elevated methane - because that's how your samples were chosen in the first place.

You can see this by looking at the distribution of sampling points in the above figure, which are clustered in certain places on the map, rather than spread evenly. To really robustly establish a link between drilling and methane contamination, a much more uniform sampling and testing program would be required. It's a shame that the Duke researchers did not do this, because they've left what could have been a really fundamental study open to criticism.

To summarise my thoughts - I think that it is likely that at least some of the incidences of methane contamination in the Duke study HAVE been caused by drilling. The example of Dimock shows a pretty clear case where of shoddy drilling practices leading to methane contamination. However, based on the sampling methods used, I'm not sure that this study, despite the media fanfare, actually adds anything to this. The real question we want to know is - are methane issues ubiquitous and inevitable, or do they represent a handful of 'bad apple' cases of poor drilling practice, the number of which can be minimised with good practice, strong regulation and good oversight? A more rigorous attempt to sample PA wells more uniformly is required (for example, many of the Duke samples do not have much/any methane in them).

Finally, keep in mind that methane, while a nuisance, is not toxic, and most private drinking wells should have filters to remove methane prior to the water entering the house. The Duke researchers also looked for other chemicals that might be associated with drilling. Opponents of shale gas often point to a smorgasbord of nasty-sounding chemicals associated with fracking fluids that they claim are polluting groundwater.

Much like their previous studies both in PA and elsewhere, the Duke researchers found no evidence for any of these chemicals. Nor would we expect them to: methane, being buoyant, has the potential to move up through the annular gaps and/or cracks left in a poorly-cemented well. Drilling and/or fracking fluids are not buoyant (i.e., they have similar densities to the brines that saturate the rocks at the depths of the shale reservoirs), so there is no force available to push them back to the surface - you may as well try to suggest that dumping sewage/pollution in London is going to contaminate the headwaters of the Thames in the Cotswolds. The water is simply flowing in the wrong direction.

So, because it's been another long and rambling post, a summary:

• lots of the water in PA is of poor quality to begin with,
• it is possible (likely) that there have been some instances of methane contamination,
• whether these cases represent a few outliers, or are more ubiquitous, is not established by the Duke study,
• and there is absolutely no evidence that any of the various chemicals associated with fracking fluids are getting into groundwater.

 

Two new studies on US shale gas and water contamination

There are many potential issues that have been associated with shale gas extraction. I think that by far the most emotive is that of water contamination. The idea that fracking could render groundwater supplies permanently contaminated and unusable is indeed a potent rallying point, making up the majority of the charge sheet in films such as Gasland.

Gasland shows a small handful of cases where gas drilling is imputed to have impinged on groundwater. There are now hundreds of thousands of shale gas wells in the US. Pointing to a handful of accusations can hardly be considered science (although it does make for good movies).

Heretofore this has been something of an issue, because there doesn't seem to have been a large amount of data available with which to go about addressing this issue. So, in this post I will explore two recent reports (one a scientific paper, one a newspaper article) that attempt to answer the question - will shale gas lead to water contamination?

The first report comes from the Scranton (Pennsylvania) Times-Tribune, via a freedom of information request to the Department of Environmental Protection to release its record pertaining to water contamination incidents. The original article can be found here.

The two statistics that initially leap out at me are that of 969 complaints drilling impacts on water quality, 77% were in fact unrelated to drilling. Perhaps this is not surprising when 40% of water wells tested by Penn State in 2011 failed at least one federal drinking water standard.

Almost everyone in the UK gets their water from a utility, almost noone maintains their own well. The utilities filter and treat the water for us, so we know we can take a glass right from the tap. Because the distances and infrastructure needed to reach rural parts of the US, it is much more common for people to have their own wells. Essentially, you go out into you back garden, drill a hole approximately 20-100m down, and drink whatever comes up, sometimes with minimal treatment or filtering. I don't know about you, but I wouldn't be prepared to drink what comes up, even in my parent's fairly rural, pleasant Hampshire pile, let alone in my own rather grubby back garden in Bristol.

There are many potential sources of contamination, both naturally occurring and manmade. Groundwater can contain naturally occurring salts and heavy metals leached from surrounding rocks, and naturally occurring hydrocarbons (methane, benzene etc) from both bacterial activity and from natural oil and gas seeps. Further human activity can add to contamination from, for example, prior industrial activity in a region, coal mining (which can be especially bad for water contamination, and there has been a LOT of coal mining in Pennsylvania, and run-off of agricultural products (fertiliser, pesticides etc).

We seem to have made the mistaken assumption that all groundwater, prior to drilling, is pure, virgin Evian-quality drinking water, meaning of course that any contamination must be due to drilling. I think this is a concept that must be addressed. In an area where 40% of the water already fails drinking water standards, differentiating a new source of contamination from the old and/or naturally occurring can be extremely challenging.

Moreover, drinking water quality may change over time: the amount and rate of water taken out of an aquifer, and the rate/amount supplied via rainfall, will affect the water composition. Bearing this in mind it's pretty easy to see how misconceptions can quickly arise: a local person notes a change in the water quality from his well. They look around, and see that gas drilling has been going on in the nearby area, and of course that is going to be the first and only thing that they blame, regardless of what any subsequent scientific tests show. This is not to in anyway accuse the 77% of unsubstantiated complainants as blaggers. However, equally it shows that we cannot simply take every complaint and assume that the little guy is right and that gas companies are nasty corporate bastards and that fracking is inherently evil. Rigorous scientific testing is necessary before blame (if any) can be ascribed.

What about the remaining cases? The vast majority are associated with stray methane leakage, although their are a couple of more mundane examples - sediment increases from road and pipeline construction, for example. It's worth keeping in context though that over 12,000 shale gas wells have been drilled in the area between 2008-2012, so these examples represent a small percentage of the wells drilled.

Moreover, the timing of the incidents is also interesting. The majority of incidents were in 2008 and 2009, when fewer wells were drilled, while in 2011-2012, when more wells were drilled, saw fewer cases. This almost certainly is associated with changes in regulations, and changes made by drillers, to ensure adequate cement casing for wells. The drop from 2008-09 to 2011-12 shows to me that shale gas extraction can be regulated.

The second report is an academic paper published in 'Applied Geochemistry' which examines water quality above the Fayetteville shale in Arkansas. This paper examined major ion chemistry, trace metals, methane content, and methane isotopic signature, in 127 drinking water wells, and compared them with flowback water from Fayetteville shale wells. 

They found small amounts of methane in many of the wells. However, there was no relationship between cases near to and far from shale gas wells, both had equal amounts of methane. Isotopic testing confirms that the gas has a shallow, biogenic (i.e. produced by bacterial activity) source. Again, these results serve to show that small amounts on methane in groundwater is a common and naturally occurring, so cannot immediately be blamed on gas drilling. The chemical analyses did not reveal any other evidence for frack fluid chemicals in the sampled water wells.

I would describe the Pennsylvania report as encouraging, but showing room for improvement - there have been a small number of genuine contamination incidents that need to be addressed. Especially encouraging is the reduction in incidents seen from 2008 to 2012 - showing the need for effective regulation in order to ensure that there is no methane migration. The Arkansas report is even more encouraging, comprehensive testing showing no evidence for either methane or frack fluid contamination across the Fayetteville shale

Frack free Frome

In the news recently - the town of Frome in Somerset has been declared a 'frack-free zone'. This is a largely symbolic gesture, given that it'll probably be years before we even know if there is any shale gas under or near Frome. But I found the minutes from the council meeting where this decision was taken made for worrying reading. You can read them here (pages 6 and 7 of the pdf):

Why is fracking a problem?
In the vicinity to where fracking takes place the gravest concern is water contamination. Many of the chemicals used in the fracking process have known negative health effects, including cancer, and can contaminate groundwater supplies, eventually polluting the water table and leaching into waterways. The industry itself estimates that 30-40% of the toxic water created in the fracking process is never recovered. The contamination of irrigation water could also affect food supplies. The fracking fluid can leach chemicals like arsenic out of the rocks making it even more toxic and so any recovered fluid (processed water) becomes a big disposal problem. Fracking in the United States has already resulted in numerous spills of these fluids, causing injury to human health and wildlife. Additionally, the fracking fluid can leach radioactive elements out of the rocks causing radioactive contamination.

Like other forms of ‘extreme energy’ (e.g. Tar Sands extraction), fracking is very carbon intensive. It uses a lot of energy (and therefore emits a lot of carbon dioxide) in order to get just a bit more energy back. Fracking has the additional problem that the natural gas (methane) that is being extracted is a stronger greenhouse gas than the carbon dioxide emitted by burning it and the method results in significant amounts of methane escaping directly into the atmosphere.

Fracking creates a large industrialised footprint on the landscape, and causes significant increases in traffic.  It can also compromise the geological structure of an area, which is of serious concern in the Mendips, where the subterranean systems are still mysterious even to experienced cavers, and where a build-up of methane could have potentially explosive results. Local councillors in Bath, including the leader of B&NES Paul Crossley, have further concerns about the potential contamination of the hot springs, the source of which lies somewhere in the Mendips, and thus on revenues from tourism.

There are, therefore considerable concerns around fracking pertinent both to our region and the greater environment.  The American experience points towards relatively small gains in energy at huge long and short term environmental cost.

If this is the sole information on which the council has made its decision then this is very worrying. No mention of any numbers or science here - numbers which would show that for several tens of thousands of wells, there have been two documented, scientifically verified cases of contamination - one at Dimock where a faulty wellbore leaked methane (no fracking fluids, no radiation), and one incident at Pavilion, which is currently under dispute as it appears that the EPA testing may have been faulty.

The 'extreme energy' paragraph is simply complete nonsense! It's a term that is being used to describe the move towards more unconventional hydrocarbon sources. It may have some validity for tar sands, which are pretty intensive to produce, but to describe shale gas in this way is complete bullsh!t. To frack a well, you pump water down a hole at high pressure for a few hours. This well will then produce gas for years. So it would be better described as 'you put a little bit of energy in, and get absolutely shed-loads back'. This is why shale gas is pushing US gas prices so low. As for the methane leakage issue, this has been firmly put to bed, including by an EU Scientific Report. Climate-wise, producing European shale gas would be better than importing gas from Russia or the middle east (not to mention the geo-political and economic impacts).

What about 'compromising the geological structure of an area'? As a geologist, I'm not even sure what that means, so it's hardly worth refuting. As for the caves - the maximum cave depths are ~200m: any likely shale gas deposits will be 2 - 3km below the surface. As far as the geologist working 2km down is concerned, these caves might as well be at the surface.

Does fracking create a significant industrialised footprint? I guess that depends on your definition of 'significant'. Yes, there will be a well pad every few miles. During drilling (usually takes about 3 months) the pad will be an acre or so, with a drilling rig about 4 storeys high. After that, the pad can be grassed over, and the well-head is topped by a 'Christmas tree', which is a couple of meters high. Yes, there will be a significant increase in truck traffic. But an increase in industrial footprint has benefits as well, something completely overlooked by Frome council. When industry grows, this creates jobs and it creates money. Even if some of the jobs that are created are specialist positions for trained geoscientists brought in from 'out-of-town', there are plenty of jobs for all walks of life - making the concrete for the drill pads, and construction of them, driving and servicing the trucks, for example. Plus all these people stay in hotels, eat in restaurants, drink in pubs, enjoy leisure activities in their spare time, and if they're there for the long haul, buy houses in the area. I can only assume that the economic situation in Frome is already pretty rosy if the council can afford to turn their noses up at this. If so, good for them, but I doubt that this is the situation across much of the rest of the country.

The American experience does not point towards small gains - the American experience points towards significant gains at small environmental cost: energy prices cut by 75%, economic booms in the shale gas areas, reviving once moribund towns and countrysides, while CO2 emission levels plummet to the lowest levels in years.

It's pretty obvious that this is a one-sided agenda. What's worrying is that these are official council documents. I'd have assumed that there would be some sort of requirement to consider these things from an impartial stand-point, considering the evidence wherever available. Clearly I'd be wrong....

My response to the Guardian letters page

With fracking all over the headlines in the last week or so, the Guardian has helpfully collated a letters page on the issue (link). The content of these letters usefully highlights many of the myths and misconceptions about fracking. This in turn inevitably leads to me getting angry, and therefore writing a blog about it (much like the credible hulk I imagine).

I thought the best way to structure this post would be to address the letters one by one. So we start with:

It beggars belief that fracking is recommended to be extended and earthquakes the only risk taken into account (Gas fracking gets the green light,  17 April). Other risks are not just theoretical; appalling consequences have already happened on a wide scale in the US. Fracking has been carried out in rural areas where people's off-grid water supplies have been made unusable by pollution. There have been cases where people cannot use water from the tap at the kitchen sink because methane comes with it, with the risk of explosions. Only half the chemical-laden water used in the process is recovered. It is then kept in lagoons on the surface where it is allowed to evaporate volatile toxic chemicals into the air.
We cannot afford the risk to our water supplies. We don't have the open spaces which have been affected in the US. Even now we are faced with water restrictions and drought. We don't have the necessary huge quantities of water available to be used and made dirty for ever. The landscape would be dominated by well heads spread out over the whole gas field. It is likely that the air around these installations would be polluted by volatile toxic emissions. Come back wind turbines, all is forgiven.
Marion Watson
Sheffield

By 'appalling consequences on a wide scale' I assume the writer means 'one confirmed incidence of a contaminated well (Pavilion, WY), and one possibly contaminated well (Dimock, PA) which has now been remediated'. These two incidences from the tens of thousands of fracked wells in the US. Hardly appalling consequence on a wide scale.

The second point, 'we don't have the necessary huge quantities of water available to be used', nicely exposes a common fracking myth: it takes something like 0.5 - 3 million gallons of water to frack each well. This sounds like a lot, and in these drought-ridden times, do we have enough water to frack all these wells? As ever, though, the key is in the context. The total leakage rate reported by water companies in the UK last year was 3295 million liters (660 million gallons) per day. Per day! If you're worried about water shortages, I'd be writing to your water companies if I were you: you could frack 200 to over 1000 wells per day on the amount of water lost by our utility companies every day. So I'll rewrite the statement. Fracking a well takes 0.5% of the total water lost through leakage in the UK in a single day.

The final point raised is 'The landscape would be dominated by well heads spread out over the whole gas field'. It seems the author has never seen a well head in her life. Here's what a well head looks like:

For sure, not to everyone's taste, but plant a couple of small trees or a large hedge next to them and they're hardly a blot on the landscape. If you're going to come out as anti-shale-gas and pro-wind on the basis of 'blots-on-the-landscape', I'd suggest you'd be more than a little confused (for the record, I'm both pro-fracking and pro-wind, I think both will be important for our energy futures).

Right - next letter, and by our only Green Party MP, no less (who I quite like in general):

The Department of Energy and Climate Change report recommending that shale gas exploration be allowed to continue says nothing about water and air pollution, nor the consequences of shale on renewables and our efforts to tackle climate change. The UK is the richest country in Europe in renewable energy potential, but the new focus on gas threatens to displace investment in those renewables, making it even harder to achieve our targets and nurture this jobs-rich sector. A number of studies have shown the overall climate impact of shale gas to be as great as that of coal. If carbon capture and storage technology is not in place, burning just 20% of the gas which Cuadrilla claims to have found in its licence area in Lancashire would generate 15% of the UK's total CO2 allowance to 2050. And despite claims from gas lobbyists that shale gas will bring down energy bills, we know from Ofgem and DECC that recent energy bill rises resulted mainly from high gas prices. Analysis by Deutsche Bank concludes that the impact of shale on bills would actually be low.
This report does not give the full picture, The government should reconsider its policy on shale gas so that we can make a genuinely green transition that will deliver both energy security and a cleaner environment.
Caroline Lucas MP
Green, Brighton Pavilion

One reason I like her is that I agree, the UK has bundles of renewable energy potential and should be making use of it. But I don't think it's true that an increased supply of gas will displace our renewables sector. Burning hydrocarbons has always been (and still is) a lot cheaper and easier than renewable energy - it's why we've been doing it for so long and so effectively. Therefore, renewables are reliant on governmental initiatives, incentives, subsidies etc. So long as the government keeps these in place, then there will be space for renewables. In the meantime, if and when we decide to burn lots of gas (as we currently do) we could either get it from our own shale deposits, or we could get it cheaply from Russia and/or Qatar. Either way, it'll be cheaper than the renewables, but it won't eat up government subsidies. If we're going to burn gas (and we are, we really are), I'd much rather it was our own, rather than lining the pockets of that nice Mr. Putin, or those nice Bahrainian Princes we've had all over our TV screens during the recent F1 Grand Prix.

In fact, we could use the billions of £s of tax raised on producing shale gas to fund renewable initiatives. If you're still worried that we're generating too much CO2, then increase your carbon tax, reduce your emissions quotas (or whatever other method you favour) and the first thing to close down will be the coal-fired power plants (which emit a lot more CO2 than gas fired power). And that's the key: managed properly (i.e., ensuring that the greenhouse-gas emissions reductions incentives that promote renewables remain in place), the main competitor for shale gas isn't renewables, it's coal. And nobody likes coal.

Next, we come to one of the classic contradictions commonly made by anti-fracking types. On the one hand, Caroline argues that shale gas will fundamentally change our energy landscape, choking off the potential for renewables to break through, while at the same time 'the impact of shale on bills would actually be low'. You can't have your cake and eat it. If you think that the impact of shale gas won't be particularly significant anyway, you can't also claim that it's going to destroy our budding renewables industry.

Finally, an I'll address a point that simply makes no sense to me; if 'recent energy bill rises resulted mainly from high gas prices' then surely a technology that increases gas supply (and therefore lowers gas prices) would help lower our energy bills?!    

Right, next letter:

The fact that a scientific committee thinks earth tremors can be reduced by using the right equipment does not mean fracking to obtain shale gas is acceptable. Fracking results in atmospheric releases of methane twice that found with conventional gas. Methane is a powerful greenhouse gas, seven times more potent than carbon dioxide over a 20-year time frame. For shale gas to be environmentally friendlier than other fossil fuels, methane emissions from fracking have to be kept below 2%. Current operations release around 10% and, in the US, the fossil fuel industry is strenuously resisting methane control legislation by the Environmental Protection Agency. Development of shale gas is impossible to reconcile with the low-carbon economy the planet so desperately needs.
Dr Robin Russell-Jones
International conference organiser, Help Rescue The Planet

I think I've dealt with this issue already here. The figure used here (10%) is above even the upper estimate from the Howarth paper. As always, no mention of how widely panned this paper has been, just a bold assertion of fact.

The next letter is fairly measured and bland, so I'll skip on one more to this:

One of the most disquieting sentences in the fracking report said information on the chemicals involved in the process had been withheld "for commercial reasons". There are references (What's the truth about fracking?, G2, 18 April) to chemicals, and chemical lubricants (and to 75% of these remaining underground) but not to what the chemicals are. Part of the planning approval process for such extraction must include an environmental impact assessment – how can this be completed to the satisfaction of the public, or courts, if the nature of the chemicals involved is kept secret? How can public confidence be won if the companies say "you do not need to know, just trust us"? That trust does not exist, so Cuadrilla – what are you using?
Martin Hemingway
Leeds

So, Martin Hemingway would like to know more about the chemicals used during fracking. Apparently they've been withheld. Martin is obviously a very lazy man (or maybe I'm just a brilliant hacker, but I doubt it). One click on the Cuadrilla website takes me to this page, which gives an overview of the fracking chemicals used. One more click takes you here, where each component of the fluid is listed in full. Unknown fracking chemicals, companies keeping secrets? Lazy pillock!

Next!

The government report on "fracking" makes it sound as safe, economic, and environmentally friendly as nuclear power. No worries there, then.
Steven Thomson
London

Can we compare fracking to the nuclear industry? More importantly, as a 'fracker' is that a comparison we'd like? After all, a lot of people who live near nuclear power plants are often in favour of them. The French in particular are quite fond of them, which is lucky for us because there are now parts of southern England that now get their electricity from French nuclear power. So long as you don't build your power stations on earthquake and tsunami-prone islands, or use Soviet-style technology, nuclear power generally seems to do ok at producing a lot of electricity for very little CO2 emissions, with very few incidences of contamination. I'm sure the writer is trying to be funny, but it's a silly letter really.

I'll skip the next one, which is more about our energy policy in general than about shale gas, and move on to this:

Nigel Smith of the British Geological Survey is either very young or has an extremely short memory if he seriously believes that "we have just had 30 years of getting our gas from the North Sea [and] it's not caused any problems to anyone". The Elgin platform is still leaking gas, and threatening a major fire, after nearly four weeks, and is predicted to continue for several months, but at least no one has died. Earlier disasters entailed major loss of life. The pollution toll will not be known for some time. In 1988 Piper Alpha, in Norwegian waters but not much further from Scotland than the Elgin, exploded, causing 167 deaths. It was producing gas and oil. Earlier, the previous record-holder, the Alexander Kielland, simply turned over in 1980, killing 123. That was an oil rig, but the same fossil-fuel lessons hold. Previously, in the same Ekofisk field, a blowout in 1977 released some 120,000 barrels of oil. So, Mr Smith, perhaps it's time to look at genuine alternatives?

It's true that there have been bad accidents in the North Sea in the past, particularly in the 70s and 80s. But Piper Alpha was in 1988, so while Nigel Smith is technically incorrect to say "we have just had 30 years of getting our gas from the North Sea [and] it's not caused any problems to anyone", he wouldn't have been far off had he said 25 years. In my view, the industry is pretty good at learning from its mistakes, and that safety record extending back for a quarter of a century is pretty good. The argument 'wouldn't it have been better if we hadn't bothered to develop North Sea oil and gas' wouldn't be likely to win much support beyond the hard-core green community. After all, North Sea oil and gas development is one of the central planks in Scotland's push for independence. If we could guarantee that shale gas development took a similar trajectory to North Sea oil/gas, I think the majority of the UK public would be in favour.

Finally, I'd add that whatever the issues with respect to the North Sea, remember that the majority of shale gas development will be on land, which makes life a lot easier and safer when you have direct access to the ground surface, rather than being separated from it by several hundreds of metres of water.

Nearly at the end now: the final letter. Thank you, dear reader, for pushing on this far.

According to the University of Texas, fracking has caused some hundred earthquakes in the US. One, in Youngstown, was recorded at just over 4 on the Richter scale. However, the government-sponsored report on fracking is a diversion, it has simply looked at the geological implications. The important issues are:
1. Water. Around 2-3m gallons of water are used for each well, which can be fracked up to 18 times. In the US there are at least 35,000 wells, so a lot of water is used over there, and here, in the UK we are facing a water shortage.
2. Pollution. The United States house of representatives committee on energy in April 2011 reported 652 different chemicals used in fracking, 29 of which are human carcinogens. In addition, the New York Times (27 February, 2011) reported the presence of radium, unintentionally extracted in the process. Between 40% and 70% of the water used comes back to the surface and has to be disposed of. Then the US Environmental Protection Agency recently announced, for the first time, that fracking may cause groundwater pollution.
3. Climate change. Increasingly large amounts of energy will be required to extract shale gas – methane. Some 2-4% of this escapes from the well, and it is several dozen times more powerful a greenhouse gas than CO². Anyway, shale gas distracts from the real task which is to find effective renewable energy because, whether you accept climate change or not, we are going to run out of gas, oil, coal and even uranium one day soon.
Fracking has been banned in Bulgaria, France, New York, New Jersey, Quebec and Switzerland, and in parts of Australia and South Africa. We need to consider the implications of the process before we allow powerful international companies to start drilling in the UK.

Firstly, a correction. The Youngstown earthquake was not caused by fracking. It was caused by geological disposal of flow-back water. When fracking is completed, the left-over fracking fluids must be disposed of. Sometimes this water is treated on the surface, sometimes companies will inject the water into deep-lying saline aquifers. It was this waste-fluid injection (and not fracking directly, as at Blackpool) that caused the quake. Again, I should stress that this was a very small earthquake, and it has happened once in several 1000 waste-water injection programs.

As for the points listed from 1 to 3:
1. Water consumption. As above, although 3 million gallons sounds like a lot, it's represents 0.5% of the water lost by our water companies through leakage PER DAY!
2. Water contamination. The US EPA has documented one case of contamination (Pavilion, WY) in the thousands of fracked wells drilled across the US. As for the hundreds of scary secret chemicals, they're all readily available on Cuadrilla's website.
3. Climate change. I agree that we should be putting a lot on energy into developing renewable energy sources. But that doesn't mean that, if we're burning gas, it'd be better for our wallets, our tax man and for our geo-political security if we burned our own gas rather than Putin's gas or the Prince of Bahrain's gas.

So, there you have it. A complete dissection of the Guardian letters page. Sorry it took so long, thanks for sticking with me. There's a lot of straw-men out there being attacked in the fracking debate that we're currently having. And yes, there is a place for genuine debate about fracking. But let's have it based on reality, not scare stories and myths.