Faulting and fracking

Recent or topical downloads and links

My lengthy review Inadequate regulation of the geological aspects of shale exploitation in the UK has been published in the International Journal of Environmental Research and Public Health (September 2020).

Submission to Surrey County Council (21 June 2019) objecting to UK Oil & Gas plc's application to develop oil production at Horse Hill (19 pages + 30 diagrams). UKOG's plans are a catalogue of supreme technical incompetence. There is also the issue of a possible link between the current drilling and the Newdigate earthquake swarm of 2018-19.

An annotated pdf slideshow of my talk to Surrey residents on 18 May 2019 about UKOG's activities at Horse Hill and the possible link to the Newdigate earthquake swarm of 2018-19.

My submission to the APPG on the impact of shale gas, a meeting held on 2 April 2019.

A handy compilation of Cuadrilla's daily reports of fracking at Preston New Road-1z, October-December 2018.These are discussed in my blog of 26 March 2019.

A short letter from myself and Stuart Haszeldine, published in Nature, 24 August 2017, on the specious definitions by the UK government of unconventional hydrocarbons and of high volume hydraulic fracturing.

My technical analysis of the Horse Hill discovery, Surrey (25 August 2017). This shows that UKOG drilled into a fault zone, thus accounting for the Kimmeridge oil flow at the so-called Gatwick Gusher. But the results cannot be extrapolated anywhere beyond fault zones. In addition, their Portland Sandstone conventional discovery needs to be re-mapped from scratch before any oil estimates can be made on it.

My objection (10 August 2017) to continued drilling at Broadford Bridge, Sussex, by Kimmeridge Oil & Gas Ltd, a subsidiary of UK Oil & Gas. KOGL is disingenuously claiming that, based on drilling into fault zones at Broadford Bridge and Horse Hill, there is a so-called 'continuous deposit' of oil in the tight Kimmeridge Clay Formation of the Weald.

The Initial Writ was lodged in the Sheriff Court of Glasgow on 31 May 2017, starting my action against the University of Glasgow to recover my research database access rights, terminated on 30 January 2016. Paras. 6-9 of the Writ set out the grounds for the court action. It appears that the university did not support freedom of academic expression by one of its lifelong members (myself) because my views on fracking run counter to those expressed by some current university employees. The action revealed the links between these staff members and Cuadrilla Resources. The legal action was funded by the £14,000 I raised from supporters in the summer of 2016 by crowdfunding. Sir Crispin Agnew QC represented me, instructed by Ms Ziqyia Riaz.

Following a day in court in June 2017 Glasgow University restored my access to essential online academic sources, and agreed to pay all costs to date. My principal opponents at the university have since either left or retired. My right to use the title Emeritus Professor, etc. was reconfirmed. I declined the request that published material about the case be removed from my website, on the ground that material damaging my reputation remains online and cannot be removed, so needs to be rebutted.

Introduction

[ The geological and environmental risks of coal-bed methane, or CBM, extraction are discussed here. ]

Hydraulic fracturing, or 'fracking' is an oil industry process which is of public concern because of the damage it may do to the environment. Under the heading of fracking I include the whole process from drilling through to production, and not just the fracking process itself.

Fracking is the only known way of extracting oil or gas from compacted, or 'tight' shale rocks, which are carbon-rich. It has come to prominence since around 2003 in the USA, and many other countries are now actively investigating their previously locked-up gas reserves, for shale is a very common rock type. Here I am concerned with several European countries, but especially the UK, because this country is pursuing an aggressive policy of encouraging shale gas extraction by fracking.

A small company called Cuadrilla Resources Limited is in the vanguard of UK shale gas exploration, with licences in two regions; in Lancashire, where it has begun a fracking programme after several years' delay. It and other companies have also started in the Weald Basin, Sussex. The Weald Basin exploration is for unconventional oil, not gas. However the Oil & Gas Authority defines the licences there to be for conventional exploration.

I summarised the fracking problem in my submission to the House of Lords economic affairs select committee, November 2013. This document was limited to 3000 words and no diagrams, so references and end notes are in a separate file.

The fault problem

I have found no authoritative study of the UK that mentions the fault seal problem in connection with horizontal fracking (sometimes also referred to as slickwater, high-volume fracking, or super fracking, to distinguish it from other methods of fracking which can safely be used). A leaky fault is a fast-track back to shallow groundwater and to the surface for methane and other gases, as well as (perhaps) for the contamination of water resources by fracking chemicals. Juxtaposed against this, the question of earthquake triggering is but a sideshow. In France fracking has been banned partly because of this risk, which was pointed out in 2011 by geologists from the University of Montpellier.

In NW Germany, a thorough study of fracking risks has been carried out by "neutral" academic experts (but funded by ExxonMobil), which includes the question of fracking through faulted zones. I have not yet digested the main report, which is in German; but one of the main conclusions of the English-language summary is that fracking in fault zones must be banned.

In England, by comparison nothing of substance has been published. Instead, we have Professor Richard Davies of Durham University, who uncritically quoted results from the USA (published incidentally, with sparse geological details, by petroleum engineers employed by Pinnacle, a Halliburton subsidiary) which imply that leakage via faults to the surface of fracking fuids and gases is not a problem. The Royal Society report of 2012 did not even discuss the question, even though it was raised in evidence submitted to the Society jointly by the Geological Society of London and the Petroleum Exploration Society of Great Britain. This evidence stated, under the heading Groundwater contamination from hydraulic fracturing:
Another possible cause for both methane and fracking fluids leaking and migrating into groundwater supplies is the fracture stimulation process intersecting with ope or unstable natural fractures and faults in the subsurface that extend upwards from the deeper prospective layers towards the surface where groundwater supplies might exist."

A 2012 British Geological Survey report, Potential groundwater impact from exploitation of shale gas in the UK, managed to avoid mentioning either faults or the permeability of the cap rock (the layers above the fracked zone) in its section on Routes to groundwater.

The USA work (even if it is to be believed) cannot be applied to Europe, because in the old continent the geology is extremely different. The English shale basins, for example, are 10-100 times smaller in area than the main US basins, but the shale deposits are 10 times thicker. Faulting is almost non-existent in the US basins, whereas it is a fundamental and important feature of the basins of the north of England, the Weald, the south of France, and NW Germany - all areas which are or have been considered for fracking. I have not yet looked at Poland.

An important new open access research paper was published in May 2015 in the prestigious Proceedings of the National Academy of Sciences (of the USA). This paper proves, from a case history in Pennsylvania, that faults and/or fractures can and do act as a conduit from fracked shale to contaminate drinking water. A few faults have been identified in the locality, but in general such faulting is extremely rare in the US shale basins. The case history, written by environmental consultants acting for the affected homeowners, is also a sad illustration of the struggle that individuals will face if their water becomes contaminated. The gas company first drilled replacement water wells, without success, all the while denying liability. Finally, after litigation, the homeowners had to be bought out and compensated.

However, the publication does not clarify whether or not the contaminated water originated in the fracked Marcellus Shale or from higher up. My reinterpretation, based on additional new data such as the precise locations of the horizontal wells in the locality, suggests that the contamination did indeed originate in the Marcellus.

Faults cannot necessarily be 'seen' in advance of drilling, for example using geophysical methods, and indeed it is common for exploration wells to drill through a fault zone without it even being spotted. Cuadrilla penetrated one or possibly two (admittedly very minor) faults when drilling its Balcombe, Sussex horizontal appraisal well without recognising them. Its Preese Hall well near Blackpool triggered earthquakes on a previously unrecognised fault. A study published by Cuadrilla in December 2014 locates the earthquakes on a fault, but misleads in having the fault distant from the wellbore, when it is clear that the wellbore deformation was caused by the earthquakes deforming the well casing, which passed through the fault zone at an acute angle.

So before this new 'dash for gas' takes place in the UK, and certainly before any further fracking is undertaken, we need a thorough study in each area, to quantify the risk of faults being the potential source of leakage back to shallow levels. Why has this not been done? There are half a dozen academic groups in the UK which could undertake this kind of research.

NB some of the links above are to publishers' websites, where payment is required for access to copyrighted articles.