Study calls for new fracking definition to close regulatory loopholes

The definitions of fracking in the UK are limited, ambiguous and inconsistent, a new study has said.

Gooseneck at Cuadrilla’s Preston New Road shale gas site, 20 August 2019. Photo: Ros Wills

The paper, published this week in the journal Energy Policy, proposes a new definition to include any well stimulation technique that make rocks more permeable.

It would close loopholes in hydrocarbon regulations, deal with current confusion and include the use of acid to stimulate the flow of oil and gas, the paper said.

The UK’s legal definition of fracking is based on the volume of liquid used to fracture rocks and release oil or gas.

The paper’s authors – a campaigner, a lawyer and a geophysicist – described this as “simplistic and inadequate”.

The issue was critical, they said, because operations that qualified officially as fracking were often subject to stricter regulations and conditions, including baseline monitoring and site visits.

The moratorium on fracking in England, in force since November 2019, applied only to fracking that met the volume definition.

For operations that did not qualify, regulators had greater discretion on controls. Some operations may not need permits, monitoring or detailed impact assessments, the authors said.

“It is due to the lack of clear definitions around fracking and historical misinformation that there is a need for a new approach based on a single robust and quantified definition of unconventional hydrocarbon.”

They said the definition should apply to:

“All well stimulation treatments of oil and gas wells which increase the permeability of the target rock volume to higher than 0.1 millidarcies [a unit of permeability] beyond a 1 m radius from the borehole.”

Multiple definitions

Associated hydraulic fracturing

The UK’s legal definition of high volume hydraulic fracturing (HVHF) dates from the 2015 Infrastructure Act.

This definition, incorporated into the 1998 Petroleum Act, specifies that associated hydraulic fracturing uses more than 1,000 cubic meters of fluid for each [our emphasis] fracture stage or 10,000 cubic meters in total.

Operations that met this definition must have 12 months of baseline monitoring of methane in groundwater and ongoing monitoring of methane emissions to air. The Oil & Gas Authority and Environment Agency (EA) must approve a Hydraulic Fracturing Plan, which assesses the risk of seismic activity. The EA and Health and Safety Executive have committed to making site visits for new fracks.

The authors said of the volume definition:

“The 10,000 and 1,000 cubic metres volume thresholds are unrealistically high because many HVHF operations around the world would not be defined as fracking if these figures are used.”

None of the three high volume fracks in the UK since 2011 met the definition of associated hydraulic fracturing, they said.

Relevant hydraulic fracturing

In 2016, the definition was  broadened in a set of regulations on fracking in protected areas. They specified that relevant hydraulic fracturing uses more than 1,000 cubic metres of fluid at any [our emphasis] fracture stage or more than 10,000 cubic metres of fluid in total.

Relevant hydraulic fracturing would include operations excluded from associated hydraulic fracturing if just one stage exceeded the 1,000 cubic metre limit, the study said.

But neither fracturing definitions would probably apply to acid stimulation because it often uses less fluid.

Minerals guidance

There is a different definition of fracking in the minerals section of national planning policy guidance. This focusses on opening, extending or creating fractures, with no reference to the volume of liquid.

This is broader still than the 2016 regulations. Operations outside those definitions, such as acid stimulation, could be included under the minerals guidance definition, the authors said, but this was not clear.

Planning applications for hydraulic fracturing would normally need to include a detailed study, known as an environmental impact assessment (EIA). But if planning authorities considered that acid stimulation, with its lower volumes, did not count as fracking, they would be less likely to require an EIA, the authors added.

Acid squeeze

Guidance from the Environment Agency describes a process of squeezing acid into rocks to enhance or create new paths to make the well more productive. The guidance does not specify volume, acid concentration or frequency of use, the study said.

“the definition of an ‘acid squeeze’ is ambiguous and may amount to an acid wash or acid stimulation in the form of matrix acidisation”.

This is significant, the study said, because activities considered to be an acid wash were treated as de minimis – having a negligible effect on the environment – and did not need an environmental permit. On de minimis operations, the EA does not monitor issues such as pumping pressure, acid volumes and frequency or timing of operations.

In 2019, the EA decided that a proposed acid squeeze operation was de minimis.

New definition

The authors said their proposed definition would:

  • avoid arguments about how much water was required to define an HVHF threshold
  • exclude activities, such as localised well-cleaning, involving water or acid treatments close to the borehole
  • exclude stimulation used in other fields such as geothermal energy, water resources or water reinjection.

They said:

“[It] also circumvents the current confusion and obfuscation by going to the purpose of the various stimulation processes, whether they involve high volume hydraulic fracturing or acid stimulation, or other methods such as gas and electrical energy injection that have been tried in the past or could be tried in the future.

They also repeated a call for the 2019 moratorium to be converted into a ban that extended to all well stimulation treatments for unconventional hydrocarbon extraction.


Acid stimulation: Fracking by stealth continues despite the moratorium in Englanduntil 27 May 2021, when the accepted text version of the paper will remain available on the Brockham Oil Watch website

Study authors: Adriana Zalucka, of Brockham Oil Watch, Alice Goodenough, of Harrison Grant Solicitors, and David Smythe, Emeritus Professor at the University of Glasgow.

35 replies »

  1. I wasted a few minutes there taking this seriously, before I scrolled down to check the “study” authors!

    No further comment, but thanks for the entertainment.

    • Just following your example, Jono. Although, I did make a comment rather than just pose a question.

      However, let me add some knowledge for you. When I start to read something, and quickly start to feel “this is a bit odd” I do scroll along to see who has written it. There is often an explanation for me. Perhaps if the article was two weeks earlier the explanation would have been different.

      MatthewS obviously did not do what I did and has been confused. I prefer not to be confused.

  2. And I read your posting. I wasn’t thinking of taking it seriously, and can’t claim it was entertaining. Still very sad, however.

  3. I’m glad the Government are considering a new definition for fracking which will now include acid squeeze methods. The old definition didn’t’ make any sense, even the Americans don’t use those volumes of high pressure liquid most of the time when they frack

    • Not wishing to spoil your narrative with facts but here is a list of typical liquid volumes currently used for fracking horizontal wells in key shale plays in North America :-

      Bakken (11,000m3),
      Barnett (15,000m3),
      Eagle Ford (30,000m3),
      Fayetteville (25,000m3),
      Haynesville (19,000m3),
      Horn river (77,000m3),
      Marcellus (23,000m3),
      Utica (40,000m3),
      Wolfcamp (30,000m3),
      Woodford (20,000m3),

  4. I hope the authors of this odd paper have also considered Leak off Tests / Formation Integrity Tests / Injection tests in their research (did they do any?). At every casing point below conductor the formation is potentially “fracked” by the definition they would like. LOTs and FITs are of course a well integrity necessity and must be undertaken to ensure well safety. An exemption is required not to do it….

    A campaigner, a lawyer and a geophysicist – they would want to make things as difficult as possible wouldn’t they? Perhaps they should have included someone with the relevant competence and experience such as an engineer?

    And the last bit is the big giveaway – “exclude stimulation used in other fields such as geothermal energy, water resources or water reinjection.”

    Why? The only reason there is a moratorium at present is induced seismicity. Are the authors not concerned about induced seismicity in geothermal wells? Perhaps they missed the induced seismicity in Korea?

    “On a November afternoon in 2017, a magnitude 5.5 earthquake shook Pohang, South Korea, injuring dozens and forcing more than 1,700 of the city’s residents into emergency housing. Research now shows that development of a geothermal energy project shoulders the blame.”

    Some further light reading for the authors:

    • Paul T. – you’ve hit the nail on the head. The fact that they seem not to mind the use of these techniques for geothermal etc just shows what we’ve always suspected – they are simply either Nimbys or anti-petroleum or both.

      It’s about time people based decisions by taking a comparative risk assessment of all energy sources. One only needs to look at the massive numbers of deaths that occur due to the collapse of hydroelectric dams or the environmental damage that occurs due to the mining of metals for the unreliables. In terms of the latter, it’s interesting to see the number of people with the hashtag BLM who seem to be promoting technologies that currently rely on child labour in the Congo; it seems that BLM matters but not as much as their backyards!

      • Simon, you are correct. For such a small section of the energy market the unreliables and other forms have a disproportionate poor history in respect of many aspects to do with how they are achieved and the cost to large groups of people on this planet. But, it seems that these issues can just be ignored when it is inconvenient to address them. The problem with that, is they can’t be going forward. More people will start to connect news of volcanoes in other parts of the world and reports of “all power is cut” and think about what then needs to be done to deal with such.

        Meanwhile, I shall write my report about how it would be better if I won the lottery each week. I’m sure it will produce the right result!

      • Simon Maynard

        Absolutely correct.

        We need a balance of energy resources for the future which gives us energy security even if the wind does not blow or the wind farms freeze

        While the government has set out the UK energy policy for the transition to net zero by 2050.

        We have to remember that irradiating green house gases completely would have a negative environmental impact.

        The earth would then probably end up as a icy planet like Mars -60 degrees centigrade or Pluto -230 degrees centigrade so think on and be careful what you wish for.

    • ‘Perhaps they should have included someone with the relevant competence and experience such as an engineer?’

      This rings a bell.

      Perhaps Cuadrilla should have started with relevant competence and experience. Their engineer didn’t see the need to carry out a 3D survey on their very first failed attempt at fracking in the UK. Maybe with relevant competence and experience they may not have had to ask the HSE a question that prompted the reply “Cuadrilla were looking for some guidance on when a cement bond log was required and who was responsible for the interpretation of the logs” Maybe with the relevant competence and experience they would not have publically stated totally incorrectly that the UK gets half it’s piped gas fro Russia. Maybe with relevant competence and experience the penny would have dropped when the Senior Vice President of the UK’s largest supplier of imported gas states,

      “We had a look at the UK sometime back as part of a global survey with Chesapeake, of the US, but we decided against going into the UK.

      “We believed we were operating in a more prolific basin in US than what the UK could offer. But I think it was primarily it was what we call the above ground risk, not so much government policy but it’s a fairly densely populated country this and there have been obstacles”

      Maybe with the relevant competence and experience they would have realised that a start up research and development company would be no match for well organised communities.

      Now that UK fracking has lost it’s investors and Government support it would be a good time to close any loopholes before mug punters get sucked into any more hype and false promises.

      • Ha ha JP – I thought we had seen the last of the CBL issue. But clearly not. Is this the 133rd time you have posted this?

        I expect you still don’t know your CBL from your USIT etc but 99% of the rest of the punters on this BB don’t either so you are not alone.

        • Indeed that was funny JP!

          The last sentence especially. Another oxymoron. They do seem a regular item.

          Firstly, what mug punters? There is NO fracking so no punters at all regarding UK fracking!

          Secondly, how will such a “report” close any loopholes?

          My report on winning the lottery should really have been worthwhile in that case.

          All this report is about is an attempt to find skeletons where there are none, but avoiding searching to more than a few sites because the skeletons may be found elsewhere and that would be inconvenient as it would show they are not skeletons but quite widespread well accepted phenomena. Obviously has kept three people occupied, other than that, can’t see the point.

          • At one of their earliest attempts to win favour with the public Cuadrilla used their relevant competence and experience to explain to locals the benefits of fracking in the green belt. When asked about the effect on the value of property around fracking sites Cuadrilla said that house prices would rise. No seriously that’s what they said. As the event was hosted by a well known presenter this can be confirmed. So according to Cuadrilla people would pay a premium to live next to a fracking site in the green belt and pay extra to listen to the noise of relentless drilling and relish the noise and disruption of lorries passing by their front doors. Flaring and venting would be another great benefit of rural life.

            Maybe hearing this amazing revelation was when Cudrilla aquired their loyal followers and got investors to part with their hard earned cash. After all it made so much sense.

            Of course we all know how it ended up.

            UK start up research and development shale gas company…… Pummelled by well organised communities.

  5. Another perfectly unbiased neutral paper published by that great neutral independent journalist!!!!!!

  6. We’d like to point out to the various commenters that this paper examines the UK/England’s legal and regulatory framework for oil and gas operations as it applies to fracking. It doesn’t consider geothermal or other technologies.

    • BOW – except that section 9.2 states “The inclusion of ‘hydrocarbon’ rules out massive rock stimulation used in other fields such as geothermal energy, water resources, or water disposal/re-injection”

    • Brockham Oil Watch

      The same processes apply for other similar industry processes like the water industry.

      Are you going to ban water aswell?

      • Interesting that UKOG are investigating geothermal for HH.

        So, they might adopt one set of technology for that, but not for oil on exactly the same site?

        And, for those with German friends in parts of that country where geothermal has been an absolute disaster, there will need to be an injunction at HH to stop them causing trouble, but for those with friends who live around Southampton, they will be overjoyed!

        That should all occupy a few for a long time to come.

    • No, BOW.

      Why not?

      The alternative jigsaw. If the pieces are difficult to get to fit, leave them out or hammer them in with a sledge hammer. No one will notice?

      Well, yes they do, so if some wish to add their names to such a report, except that will be pointed out.

      It’s like saying, “we would like to examine this use of public rights of way, because we are against certain people, but we intend to ignore those other groups using who we are not against.” Not objective, and not even disguised as such.

      [Edited by moderator]

  7. This is a consolidated response to the thankfully dwindling band of pro-fracking commentators who have chosen to comment on our newly published paper. As usual, they comprise persons unknown, going under pseudonyms, who have a smattering of low-level knowledge of the oil and gas industry. They aren’t able to criticise the study as being non-peer reviewed, because it has been published in an international journal with a solid reputation in the eponymous field of energy policy. Neither are they able to criticise our methodology or results concerning the legal definitions of unconventional extraction, so instead they resort to thinly-veiled ad hominem comments on the expertise of the authors.
    One of them asserts that the authors, comprising a campaigner, a lawyer, and a geophysicist (myself) lack the necessary ‘engineer’ co-author expertise – thereby revealing his/her ignorance of the wider geological problem of unconventional development of shale and other tight formations. This is a geological exploration problem, and has no direct relevance to drilling engineering. We pointed out that the PetroWiki website dictionary, run by the Society of Petroleum Engineers, does not even define stimulation. However, our definition makes clear that we exclude local wellbore operations (following Californian legislation) designed to affect the rocks only within a 1 m radius of the wellbore.
    The commentators do not mention our new quantitative definition of unconventional exploitation, embedding the 0.1 millidarcies permeability criterion as the universally accepted cut-off point below which formations are considered ‘unconventional’ to exploit, or ‘tight’. Does this mean that they agree with our new definition, or that they simply don’t understand it?
    One commentator lists, without citing a source, the current high volumes of frack fluid per well completion used in North American shale plays. While the figures may very well be correct, because US horizontal wells and their frack jobs are getting longer and longer, they have no relevance to our discussion. We quoted the 2015 study of water use in a quarter of a million US wells, implying that the use of more than 2000 and 2500 cubic metres in total per well, for oil and gas, respectively, means that they are unconventional. So if a water volume figure is to be used as a threshold definition (something with which we disagree), these would be the sorts of figure to use, not the 10,000 cubic metres figure quoted in current UK legislation. The logic behind this commentator’s supply of the newer, larger, volume figures is akin to saying that because modern cars can now routinely reach speeds of more than 100 mph, older models that could only make (say) 80 mph should no longer be classified as cars.
    A couple of commentators assert that because we specifically excluded massive rock volume stimulation (i.e. more than 1 m from the wellbore) in pursuit of geothermal or other processes, by restricting our definition to ‘hydrocarbons’, we are somehow being illogical or evasive. This is nonsense. A glance at the legislation being discussed confirms that we are talking about hydrocarbons, and hydrocarbons only; the Petroleum Act 1998, the Onshore Hydraulic Fracturing … Regulations 2016, the Petroleum Licensing .. Regulations 2016, etc. – see refs 10-11, 14, 19, 22, 24, 27-35, etc. The commentators have evidently failed to study the footnotes and references, or even read the paper in full, and thereby miss one of its main purposes – to examine the deficiencies in the current onshore hydrocarbon extraction legislation and regulation as it applies to fracking, and to propose a new, scientifically robust, definition that will stand up in a court of law if need be. It’s as if, to take a motoring analogy again, we had written a paper about speed limits on UK motorways, and the commentators are crying foul because we haven’t discussed country roads.
    I have long questioned the technical competence of the cowboy companies operating the current onshore UK petroleum licences. (and see, for example, John Powney’s pertinent comments above about Cuadrilla). It would appear that the apologists for this sad and failing industry are no more competent than the ‘experts’ in the companies that they are trying to defend. If they really care about promoting their views then they are free to submit a Comment on our paper to Energy Policy, where it will be reviewed and published in the usual formal manner.

    • The reply of David Smythe seems to do a good job of highlighting his ability for evidence-based research. There is absolutely nothing written in the comments by the “pro-fracking” commentators to highlight very much about their knowledge of the oil and gas industry so unless he has developed the ability to read minds then to jump to a conclusion about their “smattering of knowledge” simply demonstrates his propensity to draw conclusions based on little evidence.

      The journal in which this paper was published has a good reputation with the greens regarding energy policy but of course, there is a significant amount of underlying complexity regarding the geoscience within the paper that is beyond the professional competence of the editors and most likely its reviewers. For example, Smythe provides a definition of unconventionals, to add to the huge number that already exist and to which very few agree. The 0.1 mD permeability cut-off was originally introduced by the USA government in 1984 in relation to the tax breaks that they gave companies to encourage exploration in the USA. This definition has a number of practical problems regarding how one measures permeability/defines permeability. In particular:-

      1) Is it a laboratory-based measurement and if so what stress is the measurement made and does this include a Klinkenberg correction given that at 0.1 mD flow will be slip-dominated and will not obey Darcy’s law.
      2) Is the measurement an effective permeability (relative permeability vs absolute permeability) made at in situ saturation or is it the dried sample.
      3) How does one average the permeability? Is it the perforated interval?
      4) Or are you suggesting a subsurface measurement in which case the one will run into problems as the mobility of the fluid would normally be below that where MDT measurements are thought to be valid.

      I also notice that the authors include in their definition of unconventionals “the same rock layer acts as both source and reservoir rock”, which presumably means that they exclude plays such as the Bakken in which the petroleum is generated in the TOC-rich upper unit and then has migrated into the dolomitic siltstone in the middle unit from which it is produced.
      The reply also seems to have dual standards regarding ad hominem comments and then himself goes on, without any evidence, to question the knowledge of those commenting and refers to operators as cowboy companies.

      It was myself who presented the figures for volumes of fluids used in north American hydraulic stimulations and again he jumps to be trying his hand at mind reading again by presuming the logic behind the comment – when in fact it is quite clear that it was simply correcting a false statement made by a previous commentator. The fact that several commentators mentioned water wells and geothermal is simply to point out to readers that the article actually makes the point that the definition being used is to avoid impact on other activities, which seems odd if the real concern regarding hydraulic fracturing is safety-related.

      I think most of us are aware that we are free to make comments to Energy Policy. However, given that it is extremely unlikely that anyone in regulatory authorities (I personally know many of those involved in the UK system) will take the article seriously then it would seem to be a waste of ones’ time.

        • [Edited by moderator]

          davidksmythe while living in France which is a EU member state unlike the UK, is happy to take a UK government pension provided from current UK taxes & maybe even a pension from the Scottish university he was employed by which the student services I am sure would be great full for at this difficult time.

          He provides reports on a computer & keyboard that he may receive a undisclosed income for that is most likely made from oil or oil derivative products while effectively pronouncing the evils off fossil fuels.

          I will let the readers of this post draw there own conclusions?

          As to davidksmythe comments on my grammer & spelling etc.

          I will inform both drill or Drop & the learned gentleman that I am dyslexic [Edited by moderator]

      • Mr Maynard:

        You, like other pro-fracking commentators, hide your true identity and your supposed industry experience, qualifications, and expertise. So I have to “question the knowledge of those commenting” based upon what they say. My comments can hardly be considered ‘ad hominem’, given that I don’t know who you, or the others, are.

        Given that you can’t now criticise us on the ground that our views were not published in a peer-reviewed journal (a previous tactic employed by the pro-fracking clique), you now turn the peer review criterion on its head, by arguing that the journal may only have accepted our paper because “there is a significant amount of underlying complexity regarding the geoscience within the paper that is beyond the professional competence of the editors and most likely its reviewers.” Many readers will find that to be an astonishingly arrogant statement.

        You go on to imply that there are many definitions of ‘unconventional’, and that our 0.1 mD cut-off is just one among many contenders. Wrong – it is one of the few things on which industry, public agencies like the USGS, and academia seem to agree. It is not an original finding. But instead of accepting this fact, you divert off into a second-order discussion of how difficult permeability is to measure. If you don’t agree with the broadly accepted criterion of 0.1 mD, then please come up with a better one.

        You quote the statement “the same rock layer acts as both source and reservoir rock”, wilfully omitting the fact that we are re-quoting that statement from a DECC definition quoted a few paragraphs earlier. Furthermore, we are incorporating the DECC definition within our new, broader definition. Own goal, Mr Maynard!

        You appear to disagree with my (oft-repeated) assertion that the companies currently operating most of the UK onshore licences are ‘cowboy’ companies. I mean this in the sense of ‘cowboy builders’, of course. Last year I compiled a paper (duly peer-reviewed and published) critiquing the regulation of onshore unconventional exploitation in the UK. It comprised 14 case histories. Although the subject concerned the regulators rather than the companies themselves, many of the examples exposed the plain incompetence of the operators. Let me give you two current examples.

        (1) UKOG claimed in 2014 that Horse Hill-1 proved a ‘world-class’ oil discovery (the so-called Gatwick Gusher). They did this by conflating oil in place with recoverable reserves. Their so-called ‘limestones’ within the Kimmeridge Clay Formation are in fact ‘micrites’, or calcareous shale. They wrongly located the nearby Esso 1964 Collendean Farm-1 well in a stream bed! Their fault pattern takes an abrupt and unrealistic bend between CF-1 and HH-1 – such a curious interpretation is not needed, as I have shown; this is UKOG’s mistake, because they ignored an obvious fault on one of the seismic lines in the vicinity, and also didn’t bother using the very old Esso seismic data from the 1960s. These data are of course poor, but better than nothing where they usefully fill some gaps. Naturally these dynamite data have to be treated in technical ways which I won’t go into here, to make them compare to the more modern vibroseis seismic data. But I doubt whether UKOG’s geologists or contract interpreters are up to speed on such matters.

        Their perspective-view block models to illustrate proposed well development at Horse Hill are geometrically impossible. The high initial flow rates at HH-1 were probably due to their drilling into a fault zone, in my interpretation. This view is supported by the subsequent miserable flow rates and water production. My interpretation goes back to 2017 and earlier, and is in the public domain, so UKOG has no excuse for ignoring it. Now they wish to convert a horizontal well into an injection well. They have corrected the mis-location of CF-1, but they retain the wrong fault pattern. Now if these errors are not the mark of true incompetence, which, combined with brazen cover-ups and misleading statements to the press, justifies my epithet of ‘cowboy’ behaviour, then I don’t know what is!

        (2) I have long claimed that Cuadrilla’s geological interpretation at Preston New Road is incompetent. Tina Froud correctly pointed out a lot of the errors in her Drill or Drop guest post of 2018:

        Cuadrilla’s failure, in particular, to admit that the 300 m thick Millstone Grit Group is absent in the PNR area (as proved by the drilling), but instead to fiddle the geological interpretation so that te MGG is retained above the horizontal legs of PNR-1z and PNR-2, is a case of sticking to “alternative facts” of Trumpian proportions. Incidentally, a recent paper by Heriot-Watt geologists concurs with my interpretation.

        More recently Cuadrilla, publishing in partnership with Bristol University seismologists, now admits that it was only possible to calculate fault plane solutions for nine out of the 39,000 triggered microseismic events. A fault-plane solution is an estimation of the orientation of the fault that slipped – a very valuable piece of information. So why was it not possible to calculate more solutions – a few hundred might have been a more reasonable figure?

        Well, the valid data for the calculations were all recorded on a very limited surface seismic array, but the downhole array seismometers (the principal data gathering array) were overloaded by the motion of these larger seismic events; the shaking of the internal motion sensors ‘hit the buffers’, so to speak, so that no useful magnitude data could be obtained from them. Cuadrilla’s originally approved proposal had been for a extensive surface array, but they applied (successfully) for permission to change it to the downhole array, which turns out to have directional limitations as well.

        I don’t know whether Cuadrilla was advised by the Bristol seismologists to change the originally proposed seismometer arrays, but this was a fundamental technical and strategic error. I had opposed the change of array type in my EA consultation response, because of these potential problems, but to no avail. Even after fracking had started, Cuadrilla/Bristol could have recognised after the first day that there were problems, but no, they persisted without stopping. I call that cowboy behaviour.

        In conclusion, Mr Maynard, if you really are an earth science professional (we don’t know, do we?), AND if you regard the activities of companies like UKOG and Cuadrilla as normal, par for the course, technically sound, etc., then I respectfully suggest that you are in the wrong business.

        • I’ve been at numerous conferences that have dedicated a huge amount of time arguing about the definition of unconventionals and I can assure you that the definitions are very wide ranging. I personally view all reservoirs as a continuum and see no justification to pick some arbitrary cut-off to pigeonhole different reservoirs – the only classification that matters to me ar whether they are profitable or non-profitable to exploit at the current petroleum prices used current technology. The 0.1 mD cut-off that you propose is actually the definition used by the US government to define “tight” not unconventional. However, industry now tends to use a broader definition of tight such that a tight rock is one that requires advance drilling and completion techniques such as horizontal wells and/or hydraulic fractures to produce at economic rates. This is partly to take into account that such techniques are required to produce at economic rates in offshore reservoirs with considerably high permeability due to the high well costs. Most people working in industry don’t consider tight gas sands as being unconventional despite having permeabilities considerably less that 0.1 mD. On a flow basis one should probably use mobility (permeability divided by viscosity) in definitions as that has such a significant impact on flow rates. I guess one interesting thing about 0.1 mD is that it’s the approximate value above which extracting gas using horizontal wells with transverse hydraulic fractures makes more sense than using lateral fractures; this is explained in the theory of unified hydraulic fracture design that was developed by Michael Economides and co-workers.

          Regarding the array design for PNR, you are probably the only geophysicist that I’ve heard argue that a surface array would be better than the downhole array. Attenuation would have meant that very few of the low magnitude events would have been picked up by the surface arrays. The surface arrays also have far more errors in the location of events with respect to depth and would be far more reliant on the accuracy of the velocity model than the downhole arrays. The downhole arrays also provide the opportunity to gain a significant amount of information from the analysis of the shear waves such as the normal and tangential compliance of fractures, changes in fracture density etc. The focal plane solutions are clearly useful but it should also be noted that they are non-unique so that one can normally not distinguish between bedding-parallel slip and strike-slip faulting. I’m sure that Bristol will have advised to use a down hole array but this was also the suggestion of several experts in array design who look at the issue.

          I noticed that you have had different ideas about the geology around PNR, which i notice did not go down well in peer review. I also see no problem in not being able to identify the Millstone Grit given that it is a formation and not a rock type (i.e. its boundary does not have sufficient impedance contrast to act a strong reflector.

    • “As usual, they comprise persons unknown, going under pseudonyms, who have a smattering of low-level knowledge of the oil and gas industry.”

      As usual you are wrong. Unless 35 years in the upstream oil and gas industry working as a petroleum engineer (Northern North Sea), production engineer (Southern Gas Basin), drilling engineer and supervisor (Southern Gas Basin & Onshore UK) and various drilling roles including operational management in around 30 countries internationally in places such as the Falklands (no doubt you call them Malvinas), Vietnam, Malaysia, Angola, Ghana, Libya, Oman, Albania, Ukraine, Mauritania, Colombia, Tanzania, Yemen etc etc is only having “a smattering of low-level knowledge of the oil and gas industry.” Including having managed and executed some of the world’s largest offshore acid “fracks” and several tight sandstone hydraulic fracture stimulations.

      But you could do something useful and explain to John Powney the technical aspects of cement bond logging and how unreliable CBLs tend to be, and how difficult cement logs in general are to interpret? I assume that in your field of geophysics you will be very knowledgeable about sonic logs? He seems very hung up on Cuadrilla, the HSE and CBLs…..

      And I fully understand permeability and your 0.1 millidarcies permeability cut off but don’t have to agree with it. Does this mean the granite production in the Cuu Long Basin is unconventional or tight? I recall individual well production rates were often as high as 20,000 bpd with very little drawdown.

      • Paul – exactly – also it might be worth pointing out to Mr Powney that it is totally standard for companies to farm out the interpretation of CBL’s to service companies due to the difficulties in interpretation that you have eluded to and the fact that having in-house specialism in the interpretation of CBL logs would be very silly for companies that are only drilling a few wells per year.

      • Mr Tresto: Your declared expertise confirms precisely my point about a ‘smattering’ of knowledge. Let me illustrate this by analogy.

        A steel erector builds skyscrapers in a major city. He or she is clearly essential in their construction, but that does not mean that they know anything about why the building is being erected, or for what purpose, how planning approval was granted, and so on – that is for the developer, their architects, and the city council. I am not denigrating your undoubted expertise in drilling engineering (nor that of steel erectors), but the issue at hand, the subject of our paper, is the wider one of unconventional basin hydrocarbons and how to define them both scientifically and legally (in the UK at least). You admit to having no knowledge of this wider problem – neither of the exploration side nor of the legal side, but you (and other defenders of the fossil-fuel industry) pepper your comments with technical ‘know-how’ from you own corner, which is irrelevant to the problem under discussion. That is what I mean by a ‘smattering’ of knowledge.

        Your mention in a denigratory sense of the ‘Malvinas’ is also revealing of a colonial attitude to world affairs – an out-of-date mindset which thankfully is dying off, along with sunset industries like fossil oil and gas. Yes, I do often call them the Malvinas, for example when discussing them with several Argentinan friends who stayed with us for several months last year. I can declare a further interest in Argentina, in that my grandparents on my father’s side, both Aberdonian Scottish, met in the Argentine (as it was known) in 1910.

        While working for the BGS in c.1980 I was asked to divert from my Rockall regional work and carry out an emergency prospectivity interpretation of the seismic data around the Falklands Plateau – clearly the F&CO knew that something was brewing up in the South Atlantic. I was not told why, of course, and the hydrocarbon prospects then (and as subsequently proven) were in my view rather dismal.

        In 1997 I visited Port Stanley in the Falklands (flown in by the RAF to join a British Antarctic Survey research vessel, and back afterwards). A rather sad place, totally subsidised by the UK for its supposed territorial advantage. I was dropped off on South Georgia, and spent a week with the army garrison there. Naturally I was appalled by the 1982 war, and see no justification for Britain holding on to it any more. Both the soldiers on South Georgia and the captain of the RRS James Clark Ross (the BAS vessel) had been against the war. The captain had inside knowledge of the events leading up to the war, particularly the withdrawal by Thatcher of the Royal Navy patrol vessel HMS Endurance, informing his view.

        So your snide reference to the Malvinas, implying that I am some sort of loony leftie, merely permits me to demonstrate that I understand a bit more about that place than you, as a drilling engineer, probably ever bothered to learn while you were there.

        While we’re on the subject of drilling (I realise that it’s off-topic as far as our paper is concerned) I have only ever stood on one drilling platform, and only as an observer. But that well was the Kola Superdeep SG-3 up in Arctic Russia, which at 12,262 m vertical depth remains the deepest-ever hole drilled into the Earth. I filmed a fishing trip at the wellhead, which appears in the video I compiled of our geophysical experiments around the well (sorry about the poor technical quality of the video):
        I hope you find it interesting.

        Lastly, you say that you “don’t have to agree with” our 0.1 millidarcies permeability cut-off. Well, why not come up with a better alternative? The problem with commentators like you is that your main aim seems to be trying to find fault with critics of the fossil fuel industry; little said is ever constructive.

        • The Malvinas comment was made because I thought that is what the French call the Falkland Islands – and you live in France? Sorry to have touched a nerve. I recall that the people who live there wanted to remain British? Your comment “merely permits me to demonstrate that I understand a bit more about that place than you, as a drilling engineer, probably ever bothered to learn while you were there” is arrogant; you have no idea what my involvement was nor in what capacity, how long I was there and who I met and where I went. You would be surprised, but this discussion is pointless. Loony leftie? Surprising that got through the moderator?

          As to the “definitions” – they are fine as they are now.

          • Paul Tresto.
            No, the definitions are not fine as they are. Even the regulators cannot agree between themselves on what fracking means. The legal definition in IA 2015 has been expanded in scope several times by various legislative instruments (possibly because of a realisation that the volume thresholds were set too high in the original definition?). Still, both the PNR1 and PNR2 fracks would not qualify as fracking even under the expanded definition, despite the damage they’ve done.
            Even within a single regulatory regime such as the OGA’s, different scenarios have been communicated of when fracking becomes fracking enough to warrant more stringent regulation (through the requirement of Hydraulic Fracture Plans).
            Politicians are even more confused – quite understandably – and ministers have made various contradictory statements, not least about what operations the current moratorium actually applies to.
            I could go on about this but I won’t because the very reason to write this paper was to explain all of these issues in detail and with precision.
            The current legal and regulatory framework for onshore hydraulic fracturing in England is unnecessarily complicated, contradictory, inadequate and full of loopholes. This is what our paper examines and it proposes a new definition that would remove the complexity and more adequately capture the current unconventional oil and gas exploration and production which the operators are pursuing under the guise of conventional activities.

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