The Horse Hill oil site in Surrey has been granted permission to pump waste water underground.
The Environment Agency confirmed today it had extended the site’s permit to allow disposal of salty formation water that comes to the surface during oil extraction.
Horse Hill’s parent company, UK Oil & Gas plc, said water reinjection would help to improve the flow of oil. It would also dispose of waste liquid more cheaply, the company said.
The changes to the permit allow:
- pumping of formation and surface water into two reinjection wells
- drilling and 90-day testing of four new boreholes and associated side-tracks
- oil production from the new wells
- burning of waste gas up to 10 tonnes per day during production
- acid wash and solvent treatments to improve oil flows
In a statement today, UKOG said it would now go ahead with plans to convert the Horse Hill-2z well (HH-2z) into a water re-injector during 2022. The company also has permission to drill a second reinjection well.
UKOG’s chief executive, Stephen Sanderson, said:
“[the permit] finally enables UKOG to return Horse Hill’s produced saline formation water back to the oil-bearing Portland rocks where it originated, lowering operating costs per barrel, removing HGV tankers from congested roads and reducing the field’s overall carbon footprint. The ability to reinject makes both environmental and economic good sense”.
The Horse Hill site currently extracts oil from the Portland formation but has drilled into the Kimmeridge.
UKOG said today it was now looking at the viability of restarting production from the Kimmeridge and drilling more wells into the Portland formation.
Shares in UKOG rose rapidly on the news of the permit approval. At the close of trading, they were up more than 70% at 0.19p.
Nearly 500 members of the public, as well as parish councils and campaign groups, responded to the Environment Agency’s first consultation on the permit changes in 2019.
They raised concerns about water reinjection inducing seismic activity, following a series of earthquakes in the area in 2018 and 2019.
Other worries included gas flaring and air quality, water pollution, carbon emissions, acid wash operations, and the ability of the Environment Agency to monitor the site.
Sarah Finch, an opponent of operations at Horse Hill, told DrillOrDrop today:
“I’m disappointed that the EA have given UKOG the go-ahead to flare up to 10 tonnes of gas a day. The planning permission was granted on the basis that this gas would be used to generate electricity. With the current climate and energy crises, gas should not be viewed as a waste product.
“Also disappointing are the absence of any limits on volume or pressure regarding the use of acid and the failure to require recent seismic surveys. It’s particularly worrying given that this permit allows water reinjection, which can cause earthquakes.
“The geology around Horse Hill in particular is known to have critically stressed faults, where even very small pressure changes can trigger earthquakes. The EA appear to have ignored detailed expert submissions on this.”
Second approval awaited
UKOG is still waiting for permission from the industry regulator, the North Sea Transition Authority, to convert the HH-2z well to waste reinjection.
An addendum to the Horse Hill field development plan, submitted in 2020, has not yet been approved.
A UKOG spokesperson told DrillOrDrop today:
“NTSA and ourselves were first awaiting the EA permit approval.”
Another hurdle may also remain to UKOG’s plans.
In March, Ms Finch said she was seeking permission to take her legal challenge to oil production at Horse Hill to the highest court in the land.
She has previously argued at the High Court and Court of Appeal that Surrey County Council acted unlawfully in September 2019 when it granted planning permission for production and more wells at Horse Hill.
She has now applied to argue at the Supreme Court that the council should have taken account of greenhouse gas emissions from the use of Horse Hill oil, known as downstream or indirect emissions.
- The Environment Agency recently granted permission for waste water reinjection at Brockham, another oil site in Surrey