Proposals to reinject waste fluid from across the Weald Basin at Brockham – Q&A for EA consultation

Q1: Which issues should I raise in my consultation response?  

  1. Risk of groundwater pollution

The discharge of waste fluid into groundwater within the oil bearing formation is considered as a direct discharge to groundwater which is prohibited under the Water Framework Directive except under certain exemptions. The exemption under which Angus are applying is that the waste fluid would be returning into geological formations from which hydrocarbons have been extracted or which are permanently unsuitable for other purposes (ex. as a drinking water aquifer). Angus repeatedly states that the risk to groundwater from their proposed operations is ‘negligible’. We disagree. For starters, see the Environment Agency’s comment in their November 2018 decision document that prohibited reinjection:

The operator have not fully comprehended the risk to the groundwater and the associated pathways. There is a need to protect groundwater at depth, in the oil and gas reservoir itself (in this case both the Portland Formation and the Kimmeridge Clay Formation), as well as any groundwater in aquifers nearer the ground surface (in this case the Ashdown and Tunbridge Wells Sand Formations).

Angus propose to inject waste fluid at a depth of 750m, through Brockham X3 well drilled in 1987 and converted into a reinjector well in 2007. The well passes through the Tunbridge Sand (229m) and Ashdown Formations (381m) – secondary, potentially potable aquifers, which are likely to become more important as water shortages intensify. Here are some of the specific areas of concern:

  • Well integrity is a critical factor in waste fluid reinjection (which is done at significant pressure). One of the reasons why reinjection at Brockham was prohibited in 2018 was failure to demonstrate well integrity due to the lack of cement bond log – which Angus has now provided. The new CBL shows missing cement and sections of poor cement bond along the length of the well, including at aquifer depths. It also shows the casing is “slightly off centre for a few meters”. Various studies show a high rate of well integrity failure, up to to >40%, and to quote the famous Schlumberger statement “most fail by maturity”. The older the well, the higher the risk of casing corrosion and cement bond deterioration. Brockham X3 is an old well – drilled originally in 1987 and later redesigned for water injection – with multiple sections of poor quality cement job and it poses a potential risk of waste getting into the aquifers. Excerpts from the new CBL (which appears incomplete) read: “Between around 489m and 454m there is a section of poorer and intermediate bond.”, “Below the casing connection at 435m there is a slight absence of cement which may be due to the increased diameter of the casing collar.”
  • There is extensive faulting and folding within the subsurface of the Weald Basin due to its complicated tectonic history and this has major implications for groundwater movement. Angus points out a bonding fault arguing it works as a barrier to waste and hydrocarbon migration upwards, but it largely ignores the potential risk of faults acting as pathways for contamination of aquifers.
  • Typically it is a requirement that groundwater quality monitoring be undertaken in aquifers around oil and gas sites where groundwater activities are proposed or occurring, such as in this case. However, Angus have asked for this requirement to be removed on the basis that they have adequate mitigation measures in place. Given this company’s poor track record, concerns about well integrity and the high environmental risk of the current, wide-scope proposals for waste reinjection, we believe this application should be turned down altogether, and it (or any part of it) certainly should not be considered without the requirement for a full and robust groundwater monitoring scheme.

We have commissioned specialist input from a hydrogeologist and a geophysicist to identify potential issues or pathways of pollution into aquifers or surface water. 

  1. Reinjection of fluids can cause earthquakes 

With the onset of the Newdigate tremors in 2018, this area has become seismically active. The latest tremor was registered by the British Geological Survey in December 2020. Nobody can predict if and when a larger earthquake might strike. 

Based on analysis and studies done in the US, there is a strong relationship between earthquakes and reinjection of waste fluid for permanent disposal underground. Over time, pressure can start to build up on geologic faults causing them to slip. Earthquake risk can spread miles away from the disposal wells and persist for more than a decade after re-injection stops. 

Earthquakes can cause damage to wells and increase the risk of well integrity failure.

  1. Why should Brockham become a waste disposal site for the benefit of a private company?

Reinjecting waste fluid from production of oil back to where it came from is risky enough, but bringing waste fluid from oil and gas sites from across the Weald Basin poses a whole list of new issues. It means tankering of toxic, radioactive and salty waste fluids on rural roads to inject them for permanent disposal at Brockham. The effects of this on the groundwater environment are not understood. The specific reasons why this should not be allowed are: 

  • Unknown composition of waste fluids from other oil and gas sites has an unknown effect on the groundwater environment. Angus’s statement “The Weald Basin waters are of a similar salinity across the basin” is misleading. The salinity, toxicity and radioactivity of waste fluids depends on the geological layer from which they are extracted and also on drilling methods. Multiple oil wells in the Weald Basin target the Kimmeridge Clay Formation, which is buried significantly deeper than Portland whilst Angus’s own application highlights the very high salinity of formation water in Balcombe BA2Z (whether or not this is due to drilling brine is irrelevant because, unless a site is officially classed as hydraulic fracturing, drilling brine is combined together with formation water for the purposes of reinjection – see EA’s guidance; in any case, how would Angus know and/or demonstrate which brine is just produced water and which contains drilling or treatment fluids if they propose testing of samples in 6 months-intervals?). See also Appendix at the bottom of this page.
  • Angus say only that waste will come from “other producing fields in the Weald Basin”, but don’t specify which ones. According to procedure 2.1 of “Water Acceptance and Unloading Procedure” (p.160 of this document) lab tests would be done on imported brine every 6 months. This is not sufficient information. Given Angus Energy’s track record of repeated, brazen non-compliance, the company should not be afforded the flexibility to decide which brines to import and inject based on lab tests carried out once in a while (by the company and not the EA). This ‘open ticket’ for Angus Energy to bring and inject toxic and radioactive waste, largely unsupervised (except for the EA’s periodic site visits and documents check) is unacceptable to the local community.
  • The existing Radioactive Substances Permit for handling of radioactive wastes on site (RB3994DK) was granted on the basis that no waste fluid would be received from any other sites for reinjection into Brockham.
  • Given the current price of oil c. £44/barrel and the price of waste fluid disposal of £49/barrel (as of Jun 2019 – this cost has probably gone up), one wonders what is Angus Energy’s intention for Brockham going forward: an oil production site or a waste disposal site? Especially when one considers that recent oil production at Brockham was only 35 barrels/day (see also pt. 4 below) while the volume of reinjected water estimated by Angus is 150 barrels/day (24 m3).
  • Angus also say that “Typically, injected water should be of a broadly similar salinity to the water present in the reservoir to avoid swelling and mobilisation of clays and deposition of salts etc.” Clearly the concern here seems the ability of the to produce oil, implying that it would not be in the company’s interest to inject incompatible waste. However, given the point above, it might become more important for Angus to be able offer a waste disposal avenue than to avoid impediments to any production of oil from the Portland reservoir.
  • In their application to the EA, Angus Energy have applied for “Management of non-inert, non-hazardous extractive waste that does not include a mining waste facility.” the EA defines a mining waste facility as an area designated “to accumulate or deposit extractive waste”, but states that “re-injection of produced water is not classed as a mining waste facility.” We contend that reinjection of imported waste should not be included in this exemption and that, if Angus wish to bring waste from across the Weald to dispose of at Brockham, they should apply for a mining waste management and facility. Further, how can Angus and the EA assure local residents that the waste is non-hazardous if no testing of toxicity or radioactivity is required?
  1. The risk is too great justify declining production from an already depleted reservoir 

Angus say they need to reinject waste fluids from multiple locations in order to support reservoir pressure at Brockham to enable production of oil from the depleted Portland Sandstone – the same reservoir Brockham had been producing (intermittently) since the site was established in 1989. On 31 January 2016, production from the Portland was suspended to prepare the site and drill a new well targeting the ‘game-changing’ Kimmeridge Clay Formation. After testing, it was concluded that the Kimmeridge would not flow commercial volumes, not without fracking anyway. 

Most recently, output from Portland averaged only 35 bopd. Angus says on its website that the site has undergone “a steady and predictable decline in production rate as the asset has matured”. 

Angus says in the current proposals that it plans to extract 300,000 barrels of oil from Brockham. Even if we assume that Angus is able to reinstate and maintain the most recent flow rate of 35 bopd, it would take 23.5 years to reach the 300,000 barrels! This will take us to 2044. 

It is worth highlighting that 35 bopd makes up only 0.0031% of the UK’s daily oil consumption of 1,118,000 bopd (based on 2019 stats from International Energy Agency).

Perhaps this is why Angus was looking to sell Brockham in 2019, after the failed Kimmeridge tests. Angus also said that, if this EA permit is not granted, it would abandon Brockham, estimating the cost at £300,000 – making this ‘asset’ a clear liability.

  1. Angus Energy’s record of brazen non-compliance & questionable competence (see pt. 2 & 3 in Q2)

APPENDIX: Figure 2-1 on p. 6 of the Supplementary HRA has been manipulated and a data point (relating to Balcombe) has been covered up/removed. This is obvious when comparing this figure to Fig. 1 in the Geochemical analysis on p. 92 of the combined HRA and supplementary documents. No explanation for this is given in the text of the HRA which does not build confidence. See screenshots below to illustrate: 

11 thoughts on “Proposals to reinject waste fluid from across the Weald Basin at Brockham – Q&A for EA consultation

  1. Serious risk of Ground Water Pollution and co-existent surface water courses
    Existing regulations are implemented by Civil Servants who are NOT educated in this function . They rely on “experts” who similarly are employed to support the current “trend”

    Liked by 1 person

  2. We have to stop polluting our beautiful country if we don’t nothing will be left for our children and hundreds of years of a poisoned unlivable land we have to treat our land and earth with more respect.

    Liked by 1 person

  3. Considering this current governments commitment to green issues, I do not understand how companies such as Angus can be allowed or even considered permission for this type of contamination to be allowed and further poison our environment.


  4. Why do we have to fight one battle after another to keep our surroundings safe! It’s absolutely appalling that in this day with all the environmental issues, that it is even being considered and allowed to introduce waste systems that are damaging to our health, we will never be safe with with a government which allows such harmful waste processing to happen. How on earth can we be expected to bring up healthy children in an environment where things like this are allowed to happen 😡

    Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s