Prof Smythe: "Well" out of date

It would appear that I have a new admirer. Imitation being the sincerest form of flattery, I consider myself very flattered that Professor Smythe has created a blog in my honour, going so far as to name it "Frackland" in reflection of my own small contribution to the national shale gas debate.

Prof Smythe has featured previously on this blog, firstly when I pointed out errors in his critique of Cuadrilla's Balcombe operations, and subsequently to document his contretemps with the Geol. Soc. and Glasgow University.

In his original critique of Cuadrilla's operations at Balcombe, Prof Smythe proved himself to be ignorant of modern drilling technologies. Sadly, it seems that Prof Smythe has doubled down on his errors in a new presentation, which, in a comment on his blog, he claims "show[s] that it is James Verdon, not I, who misunderstands the technology of drilling".

In his latest piece, Prof Smythe admits to learning about geosteering and LWD at the Dart Airth CBM planning inquiry, and grudgingly concedes that one of my principal criticisms was, in fact, accurate: "It is correct that I did not at that time know about the gamma-ray geosteering technique." I would add that listening to a submission at a planning inquiry does not make anyone an expert in anything.
 
It is interesting that Prof Smythe refers to a "gamma ray" geosteering technique. I don't actually refer specifically to gamma-ray logging at any point in my original comments. There is a reason for this: there is a huge range of LWD measurements that can be made to measure the properties of the rocks through which a well is being drilled.

The motivation for this is severalfold - in addition to the real-time aspect of LWD, in horizontal wells a "well tractor" is required to pull wireline logging tools (the traditional method of well logging, done once the well had been drilled) along the horizontal section of the well, which can be time consuming and expensive. LWD obviates this need, so as a result in the last 20 years much effort has been put into developing LWD tools that can match traditional wireline tools both in terms of the different petrophysical measurement techniques, and the quality of the measurements.

If Prof Smythe thinks that LWD is limited to a non-directional gamma-ray measurement then he is still spectacularly uninformed as to the state of modern drilling technology.

Almost every traditional wireline logging tool is now available as a LWD equivalent. This might include measuring the electrical resistivity (which is particularly sensitive to whether the rock is full of oil/gas (high resistivity) or salt water (low resistivity)), the porosity, the bulk density, and the acoustic properties of the formation, in addition to its gamma-ray levels. The latest technologies can even tell you the colour of the rock you are drilling through (organic-rich rocks tend to have a dark colour), and microimaging even takes images of the rock as you go!

Equally importantly, these measurements are not taken uni-directionally. Modern LWD tools take measurements at many angles to the well bore. This enables an operator to identify the dip of the beds through which he is drilling, as demonstrated in the image below, taken from a Schlumberger Oilfield Review paper. Note that this SOR is from 1996, which gives an indication of how out-of-date Prof Smythe's comments are. Prof Smythe (and the interested reader, of course) would do well to peruse the latest offerings from the various oilfield service providers, such as this from Weatherford or this from Schlumberger.

So, how does all this tech help an operator stay in zone while drilling a horizontal well. In most cases, an operator will have prior geological data from logs run in vertical wells (such as Cuadrilla will have had from Conoco's drilling of the first Balcombe well in 1986). They will have identified marker beds from this log data, characterising the petrophysical properties of each different layer (the resistivity, porosity, density, acoustic properties, the microimages etc.). These marker beds, along with the dip information, are then used to guide the horizontal wellbore and stay in formation. If a fault is intersected, the well will find itself in a different geological layer. The operator can determine which layer this is by comparing the LWD data with pre-existing logs and, in combination with the dip data, determine where the well must be steered in order to return to the formation.

Now, if a fault is encountered that has substantial offset, it may not be possible (or economic) to steer the well back to the target formation, and the well must be abandoned. And of course it's better if an operator has 3D seismic data to help plan their wells, and to ensure that their LWD matches the 3D seismic data. I make this point in my original post, and I expect that as operators move from exploratory to production phases, we will see more 3D seismic data collected. However, LWD data alone is usually sufficient to keep a well on target, even if faults are encountered.

Importantly, however, the proof is in the pudding.

One of Prof Smythe's principal conclusions was that keeping the well within the 30m thick target layer would be a "near impossibility", "all-but impossible", and "the drilling will therefore almost certainly transgress into the Kimmeridge Clay, either above and/or below the micrite (the target layer)." Indeed, Prof Smythe goes so far as to claim that Cuadrilla will intentionally drill out of formation in order to collect samples of Kimmeridge Clay with a mind to future fracking at Balcombe, and makes the claim that Cuadrilla's activities at Balcombe were little more than a "cover story" for future unconventional work.

Prof Smythe maintains that "[his] criticism of Cuadrilla in 2013 was and remains substantially correct". However, in September 2013, Cuadrilla announced the results of their Balcombe well, and that "using geo-steering technology, the entire 1700ft was successfully drilled within the target limestone".

Now, Prof Smythe might claim that Cuadrilla are still deceiving us. If they are, it would be a odd thing to do, given that all well log data becomes publicly available after a short confidentiality period, so they'd know that they'd soon be found out.

He also makes the unsubstantiated accusation that Cuadrilla may actually have encountered a fault, and that they had been forced to stop drilling as a result:

"We do not know why the horizontal well stopped at 518 m (1700 ft). For all we know, Cuadrilla may have encountered a fault."   

This seems very unlikely. If Prof Smythe were more familiar with the full history of the Balcombe site, he would have been aware that Cuadrilla's planning consent for the site expired on the 30th September 2013. By this date they were required to have removed all of their drilling and other kit from the site. The two images below show the drilling equipment on site, and the condition to which Cuadrilla had to return the site by the 30th September.

Cuadrilla completed their drilling on the 23rd September. Prof Smythe claims that Cuadrilla stopped drilling because they had encountered a fault. I would suggest that the far more likely explanation is that they only had 7 days left before their planning consent expired, and wanted to give themselves enough time to run whatever tests they wanted to do, before removing all their kit from the site, and probably leaving a bit of spare time as well in case protestor activities caused further delays (as happened earlier in their operations).

In his original criticism, Prof Smythe made strong conclusions ("near-impossibility", "all-but impossible") , and accused an operator of intentional deceit, which should not be done lightly. I would suggest that when an "expert" claims that something is a "near-impossibility" and "all-but impossible", but then that thing happens, then those claims do not "remain substantially correct", as Prof Smythe claims. In fact, I'd think it would be considered rather embarrassing, and would draw the status of said "expert" into question. Perhaps this is why the Geol Soc asked Prof Smythe to cease referring to himself as a Chartered Geologist.

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.

BGS report on Weald Basin expected today

Update 23.5.2014: The report has now been released and is available here. The headline number is a resource of 4.4 billion barrels of oil in place.



The big news today is that the BGS report into the hydrocarbon potential of shale rocks in the Weald Basin will be released.

The Weald Basin stretches across the south of England, through the home counties from Dorset to Kent. It already hosts one very large oilfield at Wytch Farm (the EU's largest onshore oil field) and a number of smaller onshore oil and gas fields. The general public is largely unaware of these fields - I can speak from experience because I grew up almost directly above one of them - Humbly Grove in north Hampshire. I had little idea it was there until I went off to university to study geology.

In case you are wondering, here's a map of existing fields and licences, and below is a map of existing oil and gas wells drilled in the region

Caroline Lucas, Green MP: "It's not that fracking itself is necessarily worse than ordinary gas extraction"

An interview in the Guardian with Caroline Lucas, the UK Green Party's only MP, makes for interesting reading. She's currently awaiting trial for her role in the protests at Cuadrilla's Balcombe drilling site.

She has some interesting comments about shale gas development in the UK:

For Lucas, the big problem with fracking has nothing to do with the risk that it will cause earthquakes, contaminate the water table or pollute the soil. In fact, she thinks it possible that stringent regulations could minimise those risks. "It's not that fracking itself is necessarily worse than ordinary gas extraction. It's the fact that we're just about to put into place a whole new infrastructure for a whole new fossil-fuel industry, at exactly the time when we need to be reducing our emissions." The problem, in other words, is climate change.

I've long been of the opinion that, at the upper levels of various NGOs and political groups, the primary opposition to shale gas is derived from a the climate change angle, not local pollution. The scare stories about earthquakes and pollution are a stalking horse for the real issue. Climate change concerns are unlikely to mobilise local support in any significant way, hence the need to exaggerate local impacts in order to foment local opposition. It's refreshing that Caroline Lucas has come clean about this.

Balcombe's solar plant: A footprint comparison

In this week's news, the residents of Balcombe are looking to raise funds to install solar panels to power the village. The initial plan is to raise £300,000 for enough panels to power 7.5% of the village, with the intention of continuing as far as possible towards 100%.

On the one hand, I think community involvement in energy generation is a good thing. On the other hand, these projects are made financially viable via subsidies added to everyone's energy bills. Indeed, project documentation makes clear that their efforts are only made financially viable via the feed-in tariff.

The regressive way that renewable projects are currently funded is something that irks me. We spent time in Balcombe last year deploying seismometers during Cuadrilla's drilling, and it's a typical well-heeled home county village. Current solar subsidies have the effect of taking money from the average bill-payer, such as myself, who is a long way from owning any property at all, let alone a property suitable for solar panels, and handing it on a plate to wealthy landowners: people who already own buildings with large roofs on which to install panels.

That issue aside, this provides an excellent opportunity to compare the footprint of different energy sources. While the group itself don't make the connection, the way the story has been reported gives the impression that the solar developments represent in some way an alternative to the drilling conducted last summer, with a significant portion of the village opposing Cuadrilla's plans to conduct flow-tests on the well.

With that in mind, how do the two plans stack up in terms of the energy they might provide?

Balcombe water testing results

This is one I missed while away at AGU in December. Bristol's seismologists weren't the only ones doing some monitoring down at Balcombe over the summer: the Environment Agency were performing water quality analysis before and after drilling, and have published their findings in a short report.

The most striking part of the report is the foreword:

We wanted to repeat the water quality sampling during the test-drilling to see if there were any changes. However, we weren't able to do this as access became difficult during the protestors' occupation of the area in August. We did, however, collect a sample from the borehole at this time and subsequently took samples from the Lower Stumble area when it became safe for our staff to do so.

It seems that the "protectors" scored something of an own goal, actually preventing the EA from going about their testing.

Beyond that, there is little to report (hence why this wasn't picked up by the media). The borehole water was identified as containing methane prior to drilling, and methane concentrations are unchanged post drilling. These shallow methane accumulations are a naturally occurring phenomenon.

It seems there was a small increase in ammonia in some samples post drilling, although still well within acceptable limits. Although the EA do not cite any particular source for this ammonia, elevated ammonia levels can be caused by lots of people pee-ing in streams.

Seismometer Deployments at Balcombe: Final Report

Cuadrilla's drilling at Balcombe attracted a lot of headlines. In a previous post I described (mainly by way of lots of holiday snaps) the deployment of seismometers by Bristol colleagues and I.

We have now completed our data analysis, and our results are available for you to read!

Hydraulic stimulation was not planned for this phase of Cuadrilla's operations. Therefore, we did not expect to see any induced seismic events. Nevertheless, we saw this as a good opportunity to attempt several objectives:

The first objective was simply about public perception. The average member of the public does not know much about earthquakes or about seismometers. They don't really understand magnitude scales, and they are not aware of the detection capabilities of modern seismometers. We hoped that the high levels of publicity surrounding Balcombe would give us a chance to help educate the public in these regards.

However, we had two main technical objectives as well. These relate to DECC's proposed traffic light scheme, whereby operators are required to stop if they trigger events above magnitude 0.0. Traffic light schemes are common for such operations - the Swiss in particular seem to like them. However, the minimum threshold here is far lower than anything used by the Swiss. Our aim is not to say whether this is appropriate or not, but its operation does pose some additional challenges, which our work seeks to address.

The first issue stems from the Gutenberg-Richter law, which states that the number of earthquakes (N) that occur which are larger than a given magnitude (M) is given by
                             log(N) = a - bM.
where a and b are measurable constants. The BGS gives values for a and b in the UK of 3.82 and 1.03, respectively. Using a magnitude of 0.0 (the lowest cutoff for the traffic lights), this relationship tells us that over 5,000 such events occur every year. The existing BGS seismic network is not capable of detecting these low magnitude events.

In order for the traffic light scheme to work effectively, we need to be able to distinguish between the 5,000 naturally occurring magnitude 0.0 and greater quakes that occur each year, and those induced by hydraulic stimulation. This requires us to have data about the naturally occurring events, which we do not currently have. Therefore, one purpose of our array was to begin to establish baseline measurements around a potential drilling site so that we can characterise any pre-existing, natural seismicity. This is but a small start, with only 1 month of background data. In an ideal scenario we'd want to have at least a year of baseline data.

The second purpose of our array was to measure typical levels of seismic noise and detectability thresholds for small, temporary arrays such as ours. The traffic light threshold of magnitude 0.0 is often at the threshold of detectability for surface seismometers. The detectability is controlled in part by the levels of noise on the seismometers. Although you might think the British countryside is a quiet place, there are many potential sources of noise, such as trains, roads, farm machinery, rivers. We wanted to see whether a small, relatively cheap array like ours would be helpful in administering the traffic light scheme, or whether more expensive microseismic monitoring methods are likely to be needed.

So, what did we find?
Well, the most obvious thing we saw was the train, made famous by local concerns about seismic impacts on the viaduct. We saw the train on all 4 seismic stations that we deployed. Here is an example:

You can see that the train is coming from the north. It is seen on station BA02 first, which is the northernmost, and on BA04 last, which is the southernmost. BA04 is only 150m from the rail line, so you can see the biggest signal on this station.

We wanted to compare the vibration from the train with typical earthquake magnitudes. To do this we used the UK magnitude scale, which is defined as
                             Ml = log(A) + 0.95log(R) + 0.00183R - 1.76,
where A is the amplitude of the signal at the station, and R is the distance between earthquake and seismometer. We modelled earthquakes occurring directly below the drilling site, and found that a quake with magnitude of 1.5 (the same as the 2nd Preese Hall quake) produced a similar amount of vibration to the train going past at 150m.

We used an automated trigger algorithm to search our data for potential local seismic events. Sadly, we didn't see anything that looked like a local earthquake, either before or during drilling.

The seismometers that we used are actually designed to detect earthquakes from around the globe. We did spot a number of such events (called "teleseismic arrivals"). Here's an example from a magnitude 7.7 event in Pakistan:

This map shows all 25 such events that we spotted:

One of our stations was only 300m from the drilling site. We did notice that things got slightly noisier on this station when drilling started. This figure compares the background noise before and during drilling. A simulated M0.5 event is shown - this shows up above the noise for both cases.

We didn't see any events during our monitoring period. However, we wanted to work out what we could have seen, had something happened. We simulated earthquakes occurring below the drill site, with a variety of magnitudes, and ran the simulated data through our automated detection algorithm, to see what was the smallest that could be reliably identified, given our recorded noise levels

We found that magnitude -0.2 was the smallest we could see. This simulated event is shown below:

As you can see, it just peaks up above the noise. This is the smallest event we can expect to see. This is just below what is required for the traffic light scheme, so a small array like this could work. However, I'd want to see a larger number of stations to really push the detection limits below the magnitude 0.0 cutoff.

Discussion - Accurate event magnitudes?
We finish with a number of recommendations for the implementation of the traffic light scheme (TLS). A fact unbeknownst to most non-seismologists is that there are in fact a number of different magnitude scales, depending on how magnitude is measured. They are all designed to be close to each other, however they are not always exactly the same.

The most common magnitude scale is known as "local magnitude", or ML. This is basically the good ol'fashioned Richter scale, and is fairly simple to compute. You simply measure the maximum amplitude of the seismic trace, you take the distance from source to receiver, and you put it into a local magnitude equation as I outlined above.

An alternative magnitude scale is the "Moment magnitude", or Mw. This directly relates to the moment (read 'force' or 'energy' in layman's terms) released by the earthquake, and in turn to both the size of the fault and the amount that the fault slipped. Mw is slightly harder to compute - you have to look at the frequency content of the earthquake signals - but probably a better representation of the physical process occurring in an earthquake (as opposed to an empirical approximation, as provided by ML).

Small, local arrays such as ours will typically report ML. However, the dense coverage provided by microseismic arrays (as now installed at Preese Hall) often report Mw. It needs to be made absolutely clear how these different types of measurements will be factored into the TLS, because they may not be exactly the same - indeed at small magnitudes they can be different by half a magnitude unit or more. So, for example, what happens if a quake is measured with ML = -0.1 but Mw = +0.1?

Similarly, all measurements of magnitude are subject to an error. This is rarely reported for the large earthquakes you see on TV - the relative signal to noise ratios for a large event are so large that you can be sure that it is magnitude 6.5 (or whatever) ± a very small amount. However, as you enter the world of micro-seismic events, the signal to noise ratio deteriorates (as you can see in image #6 above). As this happens, the error in the calculation gets larger. Again, the incorporation of errors into the TLS needs to be clarified - what happens if an event has magnitude -0.1 ± 0.2?

These issues do not invalidate the traffic light scheme. However, given that operational decisions, and therefore potentially millions of pounds, hang on the accurate characterisation of event magnitudes, it would be helpful to iron out any potential inconsistencies now, rather than in the wake of another induced event.




In closing, I would like to thank the co-authors of this work, who don't yet have blogs of their own.

Professor David Smythe's critique of Cuadrilla's drilling plans: A comment

Update (1.8.2014): It seems that the Geological Society are very unhappy about Prof. Smythe claiming to be a chartered geologist. The Geol Soc state that this title requires "proof of continuous professional development", with the clear implication that they do not believe Prof. Smythe meets this requirement.

Glasgow University are also unhappy about being associated with the professor. Paul Younger, Professor of Energy Engineering at Glasgow stated:

"He has published nothing on [shale gas] in any proper scientific forum — no doubt because he knows he would never get past peer review with his pseudo-scientific scaremongering. He falsely claims to be a chartered geologist. That’s fraudulent. It’s wilful untruth. I am concerned about the damage to the reputation of the university by someone who never fails to use his university affiliation.”

Original Article:
This post is a comment on the critique of Cuadrilla's Balcombe drilling plans made by David Smythe, Emeritus Professor of Geophysics at Glasgow University. The key points of this critique are as follows:

• Cuadrilla's interpretation of faults in the Weald basin differs from a potentially more parsimonious interpretation.
• Cuadrilla's interpretation omits smaller faults near to the well site, some of which might intersect a horizontal well.
• Seismic data is restricted to 2D seismic profiles of 1990s vintage, making it challenging to keep the horizontal well within the target micrite layer.
• If the well does stray out of zone, it may contact Kimmeridge Clay an important potential shale resource. It is suggested that the proposed micrite target is in fact a "cover story" for the targeting of Kimmeridge shales.
• Concerns are raised that if faults are intersected, they may act as "fast-track conduits" for surface water contamination, and/or lead to the triggering of seismic activity.

My comments are as follows:

There are indeed differences between the fault interpretations made by Cuadrilla and by Prof. Smythe. Without access to more data it is probably difficult to determine whose interpretation is the more accurate. This is a fact appreciated by all geology students who have ever done a mapping project: with limited data multiple interpretations are always possible. However, disagreements between fault locations are limited to the areas south of the Bolney well, which are not in Cuadrilla's license area. Within Cuadrilla's license area, the principal area of interest, both sets of fault interpretations are closely matched.

It is argued that the lack of 3D seismic data means that it will not be possible to keep the horizontal drill within the target micrite formation, and that it will not be possible to identify if/when small faults are intersected. This criticism ignores one of the key technological developments of the last 20 years, which is closely associated with the development of horizontal drilling. That technology is called "Geosteering" (also known as "Logging While Drilling"). For more detailed info on these techniques I'll have to hand you over to google for now, but this article provides a decent explanation.

Essentially, geophysical measurements are taken continuously at the drill tip. This data tells drilling engineers what rocks they are in. They use this to guide where the drill goes, allowing them to stay within the target formation. If you read the linked article, you'll note that it even allows engineers to see when they've intersected faults. Geosteering is common practice when drilling horizontal wells in the Barnett and the Marcellus, the two most significant shale plays in the US.

I'll include here some comments on a couple of issues raised on Prof. Smythe's website, which don't appear in the linked slides but form a key part of the conclusions outlined above. In the comments on faulting in US and European basins, he argues that "faulting is almost non-existent in the US basins". This isn't the first time I've heard this suggestion, and I don't know where this meme has come from. The eagle-eyed among you will have spotted this comment in the linked Geosteering article:

"In some areas in Pennsylvania, the geology is very complex across some of our leases," Collins noted. "There are very large thrust faults"

I've even had the pleasure of seeing them myself - they tend to show up in microseismic data. You can see an example in this paper, and below is another microseismic dataset clearly showing the interaction of the stimulated stages with a fault:

(image courtesy of Microseismic Inc)

Faults are clearly not "almost non-existent in the US basins". Prof. Smythe criticises the well-known Warpinski-Fisher paper that looked at hydraulic fracture height growth for its failure to include fault data. However, the Warpinski-Fisher paper explicitly includes data from examples when hydraulic fractures have intersected faults (see slides 7 and 11 in this presentation, for example), providing clear evidence that stimulation does not create pathways from deep-lying reservoirs to shallow potable aquifers, even when faults are present.

I would also like to address the comment that "faults do not normally act as seals". This is a misleading comment. It is true that when risking a potential reservoir trap identified on seismic data, the observation of faulting on the top of an anticline would present a risk, because with seismic surveys alone it is difficult to tell whether a fault might be sealing or not, and so whether there might be hydrocarbons present, of if they might have all leaked away over geological time.

However, it is not true to claim that "faults do not normally act as seals". Fault traps - where the geometry of faults and reservoir units serve to form a trap, instead of the traditional anticline domes - are a common method of trapping oil and gas. If that last sentence didn't make sense, there are plenty of pictures on google. Fault compartmentalisation - where sealing faults break up a reservoir and prevent fluids from flowing to the well - is a common problem in conventional reservoirs. You can read about a case example here. A particularly pertinent quote is "clay-rich lithologies (i.e. shales) are likely to reduce fault zone permeability (i.e. provide better fault sealing) more than clay-poor lithologies". We know from Conoco's drilling in the 1980s that oil is present in the micrite beds underneath Balcombe. This oil has been trapped there for hundreds of millions of years. This would suggest that, even if the Paddockhurst Park Fault does intersect the target micrite formation, it is not providing a transmissive pathway to flow.

Finally on the issue of induced seismicity. It is a misconception that if a hydraulic stimulation intersects a fault, it will inevitably create a "larger" earthquake (i.e. one that might be felt by humans at the surface, such as at Blackpool). Again, this is not the case, as documented in the microseismic examples above. It is not uncommon for stimulations to intersect small faults, yet incidences of felt seismic events are extremely rare amongst hundreds of thousands of stimulations. Although in some cases event magnitudes have increased slightly upon intersection with a fault, they remain well below the threshold that could be felt at surface. For hydraulic stimulation to trigger detectable seismic events, the stress state on the triggered fault must already have optimal orientation and magnitude - that is to say the fault must already be close to it's failure state. The majority of faults likely to be intersected during stimulation will not meet these criteria, hence the lack of detected seismicity during operations in the USA, and hence the conclusion by the expert report into the Blackpool earthquakes that they represent "exceptional" circumstances.

That said, as with pretty much any subsurface activity, there is a small risk of triggering small seismic events that should be considered. DECC have already put into place strict seismic monitoring guidelines to ensure that there is no repeat of events near Blackpool. Bristol University already has seismic monitoring stations deployed around Balcombe.

I agree with some of the more general suggestions made by Prof. Smythe: more geophysical surveys will enable us to better understand the subsurface geology. This is beneficial all around - enabling operators to maximise their production efficiency while regulators can minimise any environmental risk. I expect that as potential shale gas developments move through exploration into preliminary production phases, we will see more and more geophysical data being collected (as we have already seen a new 3D seismic survey collected on the Fylde). However, I strongly disagree with Prof. Smythe with respect to current operations at Balcombe - they are not likely to pose a significant risk in terms of fluid migration from depth or from induced seismicity.

Update (04/09/2013): Another example of hydraulic stimulation interacting with faults without adverse impact is the NETL hydraulic fracturing study, which received a lot of coverage last month. In this study, researchers injected tracer chemicals along with the fracking fluid. The shale layers were at 8,000ft depth, and an overlying layer at 5,000ft depth was monitored, looking to see if the tracers appeared in this overlying formation. The microseismic data from this operation has not yet been published, but reports seem to indicate that the stimulation intersected a fault. Even so, there was no evidence for the tracers in the overlying formation, nor were any larger-magnitude seismic events triggered.

Update (05/09/2013): Of course, I've missed perhaps the best example of stimulation intersecting a fault, in fact probably the best known one: the operations near Blackpool that triggered seismic events in 2011. This is the worst-case scenario - a stimulation intersecting a fault that is optimally oriented in the present day stress field, and close enough to failure that the stimulation is capable of triggering some of the largest seismic events ever seen during hydraulic fracturing in shales. Yet even for this worst-case example, the operators were able to produce gas from the reservoir, without any suggestion of shallow groundwater contamination from this fault.

A message from the Balcombe front lines

I'm sure that if you're reading this blog, you're aware of the current protest ongoing in the village of Balcombe. The main impact for me has been a lot of radio interview requests, but also, if the Blogger stats page is to be believed, a surge of interest in this blog. For obvious reasons, the protest itself has had as much of an impact on the local community as the drilling itself. Reports from either side of the debate will tell you either that the locals are fed up to the back teeth of the imported rent-a-mob, or that the locals are joining in with gusto.

If you'll excuse me another colossal name-drop, chatting to Prof Iain Stewart after his visit to Pennsylvania for his Horizon documentary, one of the most striking impacts that he found wasn't the pollution or lack of it, but how drilling had divided communities. Sadly, it seems that this is already happening in Balcombe, as a message I received from a local resident will testify:

A few months ago, I like many had never heard of fracking! Just a few lines to put you in the picture about who I am. Malcolm Thomason is my name, a 56 year old Balcombe born & bred guy. Until a couple of weeks ago most in the world had never heard of our lovely village with a population of about 1750. Balcombe is about 16 miles due north of Brighton, 8 miles south of Gatwick Airport in the Sussex Weald. We have a lake, mill and the fantastic Ardingly Reservoir - most of reservoir is in Balcombe. We have a pub, social club and a village shop. Not a lot but its nice and mainly quiet. But in recent years the outsiders, not village types have moved here, paying vast prices for houses near the main London-Brighton rail line with easy access to Croydon & London. I would say 25/30 years ago I knew 90% of the Village and now I dont know 90%. Thats the short introduction done with !

In 1986 Conoco drilled the same site next to B2036 south of village for 23 days. The site is 600-700yds due south of my house as crow flies. In 1986 there were no protesters, in fact we were invited to view site and to see what was going on, a very interesting visit it was as well. Conoco found some oil, not in large quantities but it was there.

How things have changed in July/Aug 2013, we have now been invaded by a vast array of people of all descriptions. Another 1000 NoDashForGas folk are setting up a camp in a field from 16-21August, the same group that shut down West Burton power station for three days last year! They seem intent on shutting down also the Cuadrilla site in Balcombe as well.

Not knowing about fracking I set of to research the subject! Plenty info about if one cares to take time and look that shows in my opinion that it is not dangerous in any shape or form! Just scaremongers putting out propaganda to try and convince the gullible that its not the thing to do! I stumbled across James Verdon twitter page and read with interest his blogs on fracking and learnt a lot more than I already knew. I only wish the antis in Balcombe would view these blogs, but a lot can only see the the water being polluted, the fantastic Victorian Balcombe Viaduct finished in 1841 collapsing through an earthquake, and the blue skies turning black!

This issue is already dividing a village with people who used to talk to each other, now trying to avoid each other, a sad state of affairs i think you all will agree!

Radio 4 You and Yours Interview

On the radio again, this time Radio 4 (does this count as a promotion from 5Live?):

Talking about Balcombe on 5Live, and is the UK oil industry a victim of its own success?

With the protest ongoing outside Cuadrilla's drill site near Balcombe, it's somewhat inevitable that I'd end up on the radio again - 5Live Drive once again. I've included the whole segment, including Bianca Jagger, a man from Blackpool who finds the whole shale gas thing a little boring, Vanessa Vine from Frack-Free-Sussex who finds the whole thing very exciting, and finally I get squeezed in at the end.

Beyond giving you the chance to enjoy my honey-ed tones once more, there are a couple of points that arose from this interview that I'd like to expand on.

The first thing that came to mind while listening to the anti-fracking interviewee was the issue of geological dread in public perception of risk. The concept of 'dread' in public risk perception is well established. From Wikipedia, a dread risk elicits visceral feeling of terror, uncontrollable, and catastrophe. It was coined in an attempt to understand why public perception of risk is often very different to expert assessment of risk. It is often that sense of an unknown danger that provokes feelings of dread. It was initially used to describe feelings towards nuclear power, but I think it applies equally to things like flying (for some people), but especially GM food, and now fracking.

Quoting the interviewee, fracking is 'messing with subterranean geology', and 'we cannot legislate for the vagaries of subterranean geology, it's such a human arrogance'. It seems that the public has this idea that the subsurface is unknowable and uncontrollable, leading to feelings of dread. I would argue that while the subsurface can no doubt be a challenging environment, there are hundreds of thousands, if not millions of people, geologists/geophysicists/hydrologists/geochemists etc., for whom understanding and making use of the subsurface is the bread and butter of their day to day life.

Geologists (Iain Stewart aside, perhaps) don't talk enough to the general public. We saw this in the furore over Iain Duncan Smith's comments about shelf-stackers being more important than geologists, where geologists finally had the gumption to point out to the rest of the world how important they actually are. And we are incredibly important.

Take a look at all the objects around you and in your life. If it's not made of animal (wool, leather) or plant (wood, cotton) then chances are it's made of something extracted from this apparently unknowable subterranean geology, that apparently we shouldn't be messing with.

It might be stone, which has to be quarried, cement and concrete products made from quarried aggregates and limestone. If it's plastic or synthetic then it's made from oil. If it's metal then that metal had to be mined somewhere. Moreover, all of the energy we use involves the subsurface as well. Hydrocarbons are the most obvious example. But where does the uranium come from that we put in our nuclear power plants? What about renewable sources, surely these will take us away from that dreadful subterranean geology with which thou shalt not mess? Well, a typical wind turbine needs something close to 100kg of neodymium, which can only be found in a few places, and mining it is not exactly a pleasant process. And hydroelectric? Well, it's well established that reservoir impoundment for hydroelectric can produce large earthquakes - for example the 2008 magnitude 7.9 Sichuan earthquake, which killed 80,000 people, has been linked with the impoundment of the Zipingpu Dam. Slightly more dramatic than the Blackpool tremor I feel.

Much of human endeavor has been based on 'messing with subterranean geology'. During fracking, we can use geophysical methods to monitor exactly where the induced fractures have gone, and to ensure that they are wholly contained within the targeted shale beds. As geologists, we have to accept that the public are unlikely to fully understand what we do. However, shale gas extraction is not an uncontrolled, poorly understood process. To claim that it is is to do insult to the thousands, or millions, of geologists around the world who do this kind of thing, successfully, every day.

Speaking of success, the events in Balcombe raise a second point. I am wondering whether the current UK onshore oil and gas activities have been a victim of their own success in hiding their operations from the public for the last 50 years.

Protestors talk about thousands of well sites despoiling our beautiful countryside. Which is strange, because we already have thousands of onshore wells across our countryside. Literally, 2000 wells - you can download a spreadsheet listing them all here. 10% of these, so about 200, have been hydraulically stimulated. Yet no-one seems to even know that they are there, and certainly no-one seems to be claiming that 50% of them are leaking hydrocarbons and/or carcinogens to contaminate groundwater.

Our onshore industry has been very effective at (a) making sure that they don't cause environmental problems and (b) doing everything that they can to stay out of the public view. I grew up a few miles down the road from the Humbly Grove Field, which is here (as per my Fort Worth post, go to StreetView and see if you can even see it), yet until I went to university I didn't even know it was there.

Now, when a new well is proposed, because people don't know anything about the onshore industry, the thought of drilling in the rural UK countryside seems crazy, (indeed it even induces dread), even though there are 2000 wells already there.

It's understandable that when we seek to understand shale gas impacts we look to the US, and we try to understand the issues they have faced, and what the development has ended up looking like. However, we should also look to our own industry. If we want to know whether it is possible to conceal well pads without despoiling the countryside, we should look at our own ability to do so, not what American regulators and planning rules allow. If we want to know whether wells are likely to leak, we should look at whether our own 2,000 wells are leaking, not whether wells drilled under American regulatory and inspection regimes are leaking.

There's one major aspect of the media attention at Balcombe that has surprised me. There is ALREADY an oil well on the Balcombe site, drilled in the 1980s by Conoco. They abandoned it because the price of oil dropped to $10 per barrel, while now it is over $100. I've not seen this well mentioned in many reports from Balcombe. Has the old well has been causing problems for Balcombe for the last 25 years? I doubt it. I would love to know what it is about the new well that people see problems? Why will it be different, or more likely to cause problems, than the one that is already there? 

Seismometer deployment to monitor drilling at Balcombe

If you follow me on twitter as well as reading my blog will know that I go by the name @TheFracDoctor. This choice of name was influenced in part by the fact that I had recently finished my PhD, and as anyone who has experienced the flush of post-viva success, there is the temptation to put the word ‘Doctor’ in front of everything. 

But also it is the role of the doctor to monitor the health of his patient, and that is how I see seismic and micro-seismic monitoring – a tool to monitor the health of a fracture stimulation.

In the last few weeks I’ve had the opportunity to do this for real in the UK for the first time: deploying seismometers around Cuadrilla’s planned Balcombe well. I’ll note right now that the current Cuadrilla plan is to drill into limestone for conventional oil, with no intention of hydraulic fracturing at this stage, but we wanted to get some experience deploying seismometers for this sort of situation.

However, Balcombe is the site of the now-infamous ‘Battle of Balcombe’ and has been at the center of much debate of unconventional gas extraction (these stations were put in a month ago, well before the events of last week). Of particular focus has been the risk of seismic activity to the Balcombe Viaduct.

This spectacular bridge, built in 1841, still carries the main London-to-Brighton rail line:

After the seismic events during stimulation at the Preese Hall well, Blackpool, concerns were raised about the possibility of similar seismic activity affecting this bridge. So we decided to deploy seismometers while they drill their Balcombe well. There are no plans for fracking at the moment, so we’re not expecting any seismic activity. Our main aims were (1) to get some experience deploying seismic stations in rural England, and (2) to record baseline activity prior to drilling.

Baseline data will help us understand the noise levels in the area, which will determine the size of the smallest earthquake we can detect – obviously the lower the noise level, the smaller event you can detect. The current traffic light scheme for seismicity proposed by DECC requires events as small as M0.0 to be detected. We want to see if this will be possible with a small array of 4 surface seismometers (we will compute the expected shaking from an M0.0 event, and see if it emerges above the noise).

Baseline data will also enable to see what changes (if any) drilling activities produce.

I will post updates as and when we collect and analyse the data. For now, this seems like a good time to share some holiday snaps, so you get to learn about what we do when we deploy seismometer arrays, and what they look like.

Firstly, here’s the piece of kit that we use: a Trillium 120 seismometer:

This is a fairly standard piece of kit in earthquake seismology, capable of measuring the vibration of the earth across a wide frequency, from long periods (up to 60 seconds) up to the sampling rate of 250Hz.

To reduce the noise from things like wind and rain, they need to be buried 50cm or so under ground. Which means you have to dig a hole. I used to work on building sites during my A-levels, and I was delighted when I got my degree, knowing that my days of manual labour were over (because digging holes all day is TOUGH work). Yet, a masters degree and PhD later, and here I am digging holes all day!

Once the pit is ready, the seismometer is carefully placed into the hole:

The batteries and data logger go in the steel box next to the pit. We run cables, insulated inside fire hose, from the instrument into the box:

 

Initial covering for the instrument, to further minimise surface noise, is provided by its ‘lid’, the black dome you can see below:

Once we are happy that the instrument is working properly, we fill the hole (being careful not to dislodge the insulating cover from the instrument. We lay a waterproof sheet just below the surface, and pile turf on top as a final covering:

Finally, we put a small chicken-wire fence around the station. This is more of a deterrent than anything else: it’s not likely to stop a marauding cow, nor is it really capable of keeping out a determined rodent (animals chewing on loose cables is a real problem in many seismic deployments):

And after all that (a couple of hours work at least), you have your seismic station:

We placed 4 stations in total, including one a few hundred yards from the viaduct:

As we set this station up, we could see the vibrations from the trains going past every 5 minutes recorded on our seismometer. It will be interesting to see what caused more vibration – the Preese Hall earthquakes or the train going past at a distance of a couple of hundred yards. After all, the initial concern at Balcombe was that seismicity would trouble the bridge – even though this is a bridge that is being shaken by an express train every 5 minutes.

We enjoyed our two days in the picturesque British countryside, and we were very glad we missed all the protestors. Fortunately, the stations are all a couple of km at least from the London Road protest site, and accessible from other roads, so that’s a gauntlet we won’t have to run. The only disturbance we saw was from these guys:

So there’s our seismic deployment in Balcombe. More to follow once we’ve analysed the data.