Thursday 30 January 2014

Statements from US State regulators on hydraulic fracturing

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

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

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

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

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

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

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

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

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

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

Monday 20 January 2014

Population density in Total's new PEDLS

In the news this week I am sure you won't have missed the entry of Total into the UK shale gas market. They follow Centrica and GDF Suez as major players in the European gas to invest in UK shale gas by buying into licence areas. 

Rather than bore you with details of their business arrangements, I thought I'd take this opportunity to examine another commonly held myth about shale gas development - that the UK simply does not have enough space.

Total have bought into PEDL (Petroleum Exploration and Development Licence) blocks 139 and 140, which are in Lincolnshire. You can download a large map of all PEDLS from DECC here. I have added the approximate locations of the two adjacent licence blocks to the Google Earth image below.

The first thing you'll notice is the abundance of yellow and pink pins, these represent existing oil and/or gas wells, as per this post. Gainsborough sits atop the Beckingham Marsh oil field, which has been in operation since 1963. The field has numerous wells, and doesn't seem to cause the locals much bother. It will be interesting to see whether a similar level of opposition to shale gas develops here as we have seen at Balcombe and Barton Moss. As they have more experience than most of how the onshore industry is able to operate without causing undue disturbance, this will be an interesting one to watch.

The second thing to notice from the satellite image above is the relative sparsity of population outside of Gainsborough. We are often told that shale gas development in the UK will be too challenging due to the high population density. I think this image tells a different story.

I won't rely on a picture to prove this point, however. Instead, I will compare Lincolnshire with counties in Texas where shale gas is being extracted. I've looked to shale developments in Texas before when addressing shale development footprints, of course.

Extraction of gas from the Barnett shale in Texas is focussed on 5 counties: Denton, Johnson, Parker, Tarrant, and Wise. The following tables show population densities (people per square mile) and the number of wells in each county (pop densities from wiki, well counts from the RRC).

Density (ppl/sq mile)
No of wells

I have added Lincolnshire, which has a population density of 390 ppl/sq mile (and 342 existing oil and gas wells). Note the comparable densities between these Barnett shale counties and Lincolnshire, which sits somewhere in the middle. Only Wise County has a density that is substantially lower, while Tarrant County's population density is substantially higher. All five counties have thousands of Barnett shale wells, an indication of how the industry is capable of operating in all settings, preferring unpopulated areas where possible, but perfectly capable of operating in areas of dense population where it is required to.

I'm sure this post won't stop the endless stream of articles in the media telling us that Britain is too crowded for shale gas development to be possible. At least you, dear reader, will now be a little better informed. 

Thursday 16 January 2014

Extended reach drilling

There are two key technologies that have enabled gas to be extracted economically from shales. Hydraulic fracturing is the technique that has garnered all of the attention. However, of equal importance is extended reach lateral drilling: turning the drill bit horizontally to drill sideways for several kilometers.

This technology was developed in the 1980/1990s - this graph shows the number of horizontal wells drilled in the US through the late 1980s to mid 1990s.

The number of horizontal wells has subsequently boomed, as the shale revolution has spread across the US - as the next figure shows for the Barnett:

Typical shale wells extend between 2 - 4 km in length. However, it is possible to go much further than this. Some of the longest "extended reach" laterals were drilled in the UK in the 1990s, allowing the operators of the Wytch Farm oil field to access reservoir compartments under Poole Harbour and the English Channel from their onshore drilling site.

The scale of these extended reach wells can be difficult to contextualise, but I'm going to try, using an image taken from Dr Ian West's incredibly comprehensive website (warning - for real geo-geeks only).

Dominating this cross-section is a profile of a Wytch Farm extended reach well. Staying topical (as ever), I will use the recent drilling at Barton Moss as a comparison. The extended reach well is over 10km long. If this well were being drilled at Barton Moss, outside of Manchester, then the toe of the well could reach Albert Square in the city centre. To represent this, I have added images of the Barton Moss drilling site and Albert Square to Ian West's image.

The well targets layers over 1.5km deep. This is equivalent to over 5 Shards, stood end on end. So I've also added a Shard, to scale, to the image.

Ian's image also compares the depths of various shale wells, including the rather shallow layer targeted at Balcombe, and deeper wells targeting the Bowland shale in the UK, and the Haynesville in the US. The Barton Moss well will also extend to 3km.

I don't have a particular point to make with this post, I just came across Ian's image while preparing an exam for Bristol's undergrads, and wanted to share how spectacular it is, when you consider the scales involved. Most shale wells in the UK will not extend to 10km. However, the Wytch Farm extended reach wells show what can be done, should the need arise in particular, difficult to reach areas.

Tuesday 14 January 2014

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.

Monday 13 January 2014

Fracking controversy and communication: Latest public perception survey

We all tend to like to read things that conform to our own opinions. It's therefore not unreasonable for me to assume that the majority of people reading this support shale development. Based on a recent paper from a group at Yale published in the journal Energy Policy, I can therefore assume that you are old, male, of right-leaning political ideology, with better than average formal education and qualifications, and preferring to get your news from television rather than newspapers.

Meanwhile, household income, race and 'individualistic world-view' do not have any correlation with support or opposition to drilling.

I should just make clear: these results apply to surveys conducted in the USA only.

Perhaps the most significant finding is the persistent lack of familiarity among the general public with fracking and shale gas development, despite continued media discussion of the subject. 39% or survey respondents had heard "nothing at all" about hydraulic fracturing, 16% had only heard "a little", and a further 13% answered don't know. This means that over 50% of the population are still very unfamiliar with the issue.

When "top of mind" associations with fracking were explored, 58% either didn't have any associations, or had associations that were irrelevant, such as references to BattleStar Galactica (a sci-fi series where "fracking" is used as a swear-word).

Perhaps unsurprisingly, 58% of respondents were undecided about whether they support or oppose shale gas development, with the remainder split fairly evenly between support and opposition, according to the social and demographic divisions outlined above.

So it seems that the public is still woefully uninformed about what shale development entails (and what it does not entail). Clearly, we have a long way to go.

Friday 10 January 2014

Flares at Barton Moss

I will begin this post with a caveat - any movement or group will attract its fair share of idiots, with whom the majority of that movement would prefer not to be identified with. For example, there are plenty of people who seem to support shale development with whom I would prefer not to be associated.

Nevertheless, having in recent months experienced at first hand dishonesty from an anti-fracking protest group, this post seems necessary, although I am loathe to write it.

In recent weeks we have seen continued protest outside IGas's drilling site near Manchester. While this protest hasn't attracted quite the same amount of media attention as Balcombe did (perhaps the greater distance from London is a factor), the apparent firing of a flare gun at a police helicopter landing at Barton airfield did make many national news outlets.

The accusation prompted a rapid denial from the organisers of the protest camp. However, comments on blogs associated with the camp appear to paint a different picture (see the comments on this blog).
Again, another caveat - while these posts, apparently from protest camp members, seem genuine, there is no way of confirming this, so I would welcome any correction in this regard if required.

These posts appear to show that the protest organisers knew that a flare had been fired, and who had fired it, but that the negative publicity attracted by admitting this would have been too difficult to face, and therefore the decision for outright denial was taken instead.

The purpose of this post is not to criticise the main body of protestors. There will always be people willing to hijack genuine protests for more nefarious ends, and I can imagine that preventing this from happening is a very difficult challenge for organisers. It seems that they have acted swiftly in ejecting the flare-firer from their camp.

My particular concern, however, is the lack of honesty from the protest organisers. Rather than admit to an idiot, now ejected, in their ranks, they have chosen outright denial.

Both sides of the shale debate will of course always try to marshall the available evidence such that their position seems the more reasonable - this is the nature of debate over heated topics, particularly when further subjected to the polarising glare of the media. However, in this case the sheer chutzpah to issue a flat out denial, when knowing this not to be the case, shows in my opinion a rather concerning attitude to honesty.

Wednesday 8 January 2014

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:

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.

Monday 6 January 2014

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.

Thursday 2 January 2014

FOI information from DECC - Well integrity in the UK

A recent FOI response from DECC regarding historic drilling in the UK makes for interesting reading. I've often mentioned the thousands of existing wells in the UK, both onshore and offshore, which have been drilled, operated and abandoned without incident, and the implications these have for future shale gas drilling in the UK. I've taken the liberty of doing a wholesale copy-and-paste, because this is fairly fundamental stuff:

(Questions in italics, DECC responses in bold)

The first question discusses offshore wells:
In relation to offshore gas/oil wells which fall under UK Government jurisdiction:
a. How many wells are currently in operation (wells not rigs)?

  • There are about 25 offshore wells currently drilling
  • Some 3360 offshore wells have been completed for production (ie are either producing oil and /or gas or are shut-in)

b. How many abandoned wells are there?

  • Approximately 6500

c. How many operating wells with cementation integrity issues have been reported within the last 5 years?

  • DECC does not hold this data

d. How many abandoned wells with cementation integrity issues have been reported within the last 5 years?

  • DECC does not hold this data

e. How many leaks from operating wells have been reported within the last 5 years?

  • Any release of oil and/or chemicals from offshore installations, including wells and pipelines, must be reported to DECC Offshore Oil and Gas Environment and Decommissioning (OGED) using a Petroleum Operations Notice No.1 (PON1). Details of PON1s received by the Department are published on our website at the following link As far as DECC OGED is aware, no leaks have been reported for operating wells during the last five years, but a leak was reported from a suspended well in the Elgin field that attracted media attention (further details can be found at and a recent review of all suspended wells on the UKCS confirmed that there were minor gas leaks from four shut-in production wells.

f. How many leaks from abandoned wells have been reported within the last 5 years?

  • As far as DECC OGED is aware, there have been no reports of leaks from abandoned wells in the last 5 years.

g. Does the UK Government keep records of abandoned wells with leaks / cementation integrity issues?

  • Information in relation to leaks from abandoned wells is held by DECC.

The second question discusses onshore wells
In relation to onshore gas/oil wells in the UK:
a. How many wells are currently in operation?

  • DECC requires monthly production reporting on a field basis, not a well basis. Reporting individual well operations is not required on licences issued before 1965, but we estimate there are currently about 300 onshore wells in production.

b. How many abandoned wells are there?

  • Records for wells drilled before the 1960’s are not reliable so we can only estimate that there are about 1500 abandoned wells.

c. How many operating wells with cementation integrity issues have been reported within the last 5 years?

  • None

d. Where are these wells?

  • Not Applicable

e. How many abandoned wells with cementation integrity issues have been reported within the last 5 years?

  • One

f. Where are these wells?

  • This was a well in Stafforshire and the integrity issues have subsequently been dealt with.

g. How many leaks from operating wells have been reported within the last 5 years?

  • None

h. How many leaks from abandoned wells have been reported within the last 5 years?

  • None

i. Does the UK Government keep records of abandoned wells with leaks / cementation integrity issues?

  • DECC does not keep such records – but regularly liaises with the Health & Safety Executive in relation to such issues.

The final questions relate to hydraulic fracturing:
3. During gas / oil exploration for conventional targets, are wells hydraulically fractured?

  • Yes, some are.

4. During gas / oil exploration for unconventional targets (e.g. shale, coal bed methane), are wells hydraulically fractured using exactly the same technique for conventional targets?

  • The volume of injected fluid is significantly bigger for shale gas, but similar and small volume for conventional and coalbed methane.

5. During gas / oil exploration for unconventional targets (e.g. shale, coal bed methane), does high pressure, high volume slick water hydraulic fracturing (often referred to as fracking) take place?

  • Yes, for shales.

6. If yes, please provide evidence to state at what point of the process this occurs (e.g. initial drilling, pressure testing, sampling etc).