This blog is based on our submission to the All PARTY PARLIAMENTARY GROUP ON THE IMPACT OF SHALE GAS – TRAFFIC LIGHT SYSTEM, held on 2 April 2019.

Our submission focused on the fact that there is no TLS in the Weald basin because the regulatory regime doesn’t view the operations taking place here as fracking. Fluid injections under pressure up to fracture pressure are allowed at Horse Hill and elsewhere in the Weald (and beyond), but there is no monitoring or reporting of injected fluid volumes, injection pressures or even dates of these operations!

Acid-based stimulations already are or will be a relevant concern at sites across the South East of England (mainly in Surrey and West Sussex plus Isle of Wight) as well as places such as Wressle in Lincolnshire, Ellesmere Port in Cheshire and West Newton in East Yorkshire.

Acid stimulations involve pressurised injection of fluids underground, including acid in various concentrations, at below hydraulic fracture pressure (matrix acidisation) or above (acid fracturing). These types of stimulations, along with high volume hydraulic fracturing, should be seen as forms of fracking. Indeed, in California, where there is a history of extraction using the various methods, fracking bill SB4 (2013-14) regulates hydraulic fracturing and acid stimulation treatments at any applied pressure in exactly the same way. In Florida, a heated debate is taking place right now about the proposed bills banning hydraulic fracturing, some including matrix acidisation and some leaving it out.

Source: David Smythe

In the UK, the regulations of acid stimulations are virtually non-existent. This includes induced seismicity regulations. The Traffic Light System only applies where a Hydraulic Fracture Plan is required, although it seems not in all cases, as the Oil and Gas Authority retains discretion over the details required in an HFP. It is not clear either for which operations an HFP is required, but in any case, an HFP would never be required for operations intended at below hydraulic fracture pressure. (See below note: When is Hydraulic Fracture Plan Required?)

Operations proposed in the South-East are never described (by the operators) to the regulatory agencies as any kind of fracturing. In fact, they are not described as stimulation at all, but rather as acid wash, arguably exploiting the loophole in the system created by the lack of a clear definition of what is acid wash and what is acid stimulation. The permitting of these procedures lies with the Environment Agency, which is the only regulatory body in the UK to even make a reference (although in very vague terms) to acid stimulation. By calling their intended operations acid wash the operators are also able to escape environmental regulations though de minimis exclusions.

Despite the procedures being described as acid wash, the pressure at which they are allowed by the EA to be performed is anywhere up to hydraulic fracture pressure.[1] [2] And for these types of operations, an HFP is never required, nor is the reporting of dates/timings of treatment, volume of injected fluid or pressure at which it was injected. Environmental permits for the so-called acid washes are issued based on “operator intent” and there is very little monitoring of what actually takes place once the permit is issued. Monitoring is limited to visual observations of equipment on surface during occasional site visits (for example we were told by the EA on 4 Feb 2019 that heir most recent routine site inspection of Horse Hill occurred on 23 August 2018), which might include on site document check, for example of waste records.

This is a stark contrast with the type of monitoring and reporting required for high volume hydraulic fracturing operations, which includes daily reporting of injection summaries and charts, such as the example here.

Hydrochloric acid at Horse Hill – photo taken in July 2018

Hydrochloric Acid with Additives – photo by Horse Hill Monitoring Post taken on 21 Jan 2019

According to analysis by David Smythe, Emeritus Professor of Geophysics in the University of Glasgow, the Horse Hill-1 well was drilled into a fault zone.  And the assessment of Professor Stuart Haszeldine, Dr Cavanagh and Dr Gilfillan at the University of Edinburgh supports the concern that oil exploration at Horse Hill triggered the recent swarms of earthquakes around Newdigate, possibly also by bleeding the well annulus to manage pressure prior to testing. Therefore, it could be inferred that anything that has the potential to change the downhole pressure, either to increase it or to decrease it, could induce seismicity. And if that is correct, then even activities such as an acid wash under a pressure slightly greater than formation pressure could be responsible for earthquakes. And even more so if the acid is applied at a greater pressure, approaching hydraulic fracture pressure.  Moreover, there is no monitoring in place to ensure that the injection pressure never exceeds fracture pressure. This is left to the operators themselves to monitor.

In addition, the Cuadrilla data on fracking at Preston New Road (example in Appendix 2) confirms that on several occasions the company put some (1 or 1.5 cu m) of 15% Hydrochloric acid into the well, presumably at the start of the frack.  So they have been, at least partially, acid fracking already.  This should also be a strong indicator that the Traffic Light System should apply to acidisation and acid fracking as well.

We therefore propose that the Traffic Light System (along with all the required reporting and monitoring) should be extended to include all pressurised injections at any applied pressure, and that it should be considered whether other operations that have the potential to induce seismicity should also be included.

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When is a Hydraulic Fracture Plan Required? 

The Oil and Gas Authority’s Consolidated Onshore Guidance (Dec 2017) says that HFP is required when hydraulic fracturing is proposed as part of completion. It also says: If the proposed injection volumes fall below the BEIS associated hydraulic fracturing thresholds, the OGA may decide less information or monitoring is appropriate, but an HFP will always still be required. This implies that an HFP is always required for operations which exceed hydraulic fracture pressure.

However, in May 2018, as part of oral evidence given to Communities and Local Government Committee regarding planning guidance on fracking, Tom Wheeler, Director of Regulation at the OGA, seemed to have contradicted this guidance suggesting that HFP is always required only when the operations meet definitions set out in legislation[3]: “We use the Infrastructure Act definition as clarified by the Secretary of State last year to determine when a company needs to submit what we call a hydraulic fracture plan.  If a plan does not meet the water-based tests that are set out in the legislation, we would not always require one.  We reserve the right in guidance to require one should we think there are risks of seismic activity as a result of it.  We would always require a hydraulic fracture plan when it meets the tests set out in the Infrastructure Act.  We find the definition useful and we rely on it for that purpose.”

[1] “The activities outlined in the Waste Management Plan and any of the application supporting documents does not include proposals for well stimulation techniques above the fracture pressure of the surrounding target formations.” P.36 https://bit.ly/2WonKQ2

[2] See here, pink highlight

[3] Q123: https://bit.ly/2YuDi6C