Landmark shale gas study shows no groundwater problems

One of the difficulties in the current shale gas debate is that good data is hard to come by. Operators collect lots of data from around their sites, including water sampling to test for pollution, and geophysical monitoring to track where the fractures went during stimulation. However, this data is often considered commercially sensitive, so it rarely sees the light of day.

A government-sponsored project would be very useful, because it would provide a test-bed for an extensive monitoring program. All data could then be made public, and the claims of all those involved in the shale gas debate openly tested.

This is exactly what has been happened in the USA, with the final report released this week. The US National Energy Technology Lab (NETL) sponsored a monitoring program at a hydraulic fracking operation in Greene County, Pennsylvania. The monitoring program consisted of 2 parts: microseismic monitoring to track the fractures created by the stimulation, and geochemical sampling in overlying layers to test whether any contamination has occurred. Most importantly, because the data is publicly available, it's a great opportunity to talk through the anatomy of hydraulic stimulation.

The first stage of shale gas extraction is to drill horizontal wells through which the fracking will be done. The figure below shows a map of the lateral wells drilled. Those in the yellow box were the 6 wells that made up the NETL study.

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.

ReFINED well integrity

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

This follows ReFINE papers on induced seismicity, and on hydraulic fracture height growth. Their approach in each of these cases is to use as much data as they can possibly get their hands on, with little thought for quality control, or on whether they are comparing apples with apples. In their own words:

This paper draws on a variety of datasets, mostly published, but in some instances sourced from online repositories or national databases, and follows the approach of Davies et al. (2013). In that study, the risk of induced seismicity due to hydraulic fracturing was reviewed, and intentionally included all datasets in the public domain that were considered to be reliable, rather than de-selecting any data (Davies et al., 2013). This inclusive approach has a drawback because well barrier and well integrity failure frequencies are probably specific to the geology, age of wells, and era of well construction (King and King, 2013). A wide range of failure statistics is therefore reported, and although they are presented on a single graph to show the spread of results, this is not intended to imply that direct comparisons between very different datasets (i.e. size, age of wells, geology) can be made.

This means that data from recent drilling in the Marcellus (which is probably relevant) is presented alongside less relevant data from offshore wells (drilling offshore is always a more challenging prospect, with hundreds of meters of water between your platform and the well-head), from China, or even from the 1920s in California.

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.

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'.