The Environment Agency has begun a public consultation on an environmental permit application for Doe Green, a coal bed methane production site near Warrington.
The site was built before legislation required it to operate under an environmental permit. But the regulations changed in 2013 and required operators of oil and gas sites to apply for a mining waste permit.
In 2015, campaigners concerned about operations at Doe Green said they were “staggered” to discover it operated legally without a permit (DrillOrDrop report).
At the time, the EA said it had begun a programme to bring all onshore oil and gas production sites under the environmental permit regulations. It said sites would be required to apply for a permit during 2015 and 2016. Doe Green already has a permit for handling naturally occurring radioactive material.
DrillOrDrop has compiled this information from the environmental permit application documents.
Application reference: EPR/EB3506KZ/A001
Permit type: Mining waste operations
Applicant: Wardell Armstrong consultants for INEOS Shale
Public consultation period: 13 January-10 February 2017
Location: 860m to the west of Penketh, Warrington
Address: Doe Green Coal Bed Methane Facility, Farnworth Road, Penketh, Warrington, Cheshire WA5 2TU
Site size: 7,121m2
Access: Off the A5080, Farnworth Road
Surrounding landscape: Farmland
Site history: Construction in 2006. Gas production and electricity generation began in June 2009. INEOS Shale took over operations from IGas in April 2016.
- The application mentions four wells: DG1 – logging well (4,036ft); DG2 and DG3 – production wells (3,726ft and 3,438ft); DG4 – suspended after failing to produce gas in sufficient volumes (4,350ft)
- Gas processing skid, which regulates the pressure of gas delivered to the generator set
- Pump and control unit, which controls water and gas pressure
- Tanks: two tanks (20,000 litres and 7,500 litres) to store and treat process water recovered from the well. A third tank (33,000 litres) stores excess water that requires off-site disposal.
- Oil interceptor and storage tank which collects rainwater falling on the site
- Two 21,000 litre effluent storage tanks for human waste and grey water, emptied by tanker
- Generator compound containing generator, storage containers, lubricant and coolant store, office
- Electricity substation
- Security and site office, washroom and mess room
- 2m high security fencing with anti-climb topping
- Gas rich with methane is extracted from DG2 and DG3 wells.
- Water pressure in the coal seams is lowered, allowing gas within the coal to flow to the surface
- Water flows from the coal into a sump which forms the base of the well bore
- If water levels rise the sump is dewatered by pumping water from a stock tank at high pressure
- Water and gas separate below the surface and the gas reaches the surface through a tubing annulus
- The water falls into a collection sump at the base of well, from where it is pumped to the surface
- Gas from the well head flows through a conditioning plant to the 400kw generator, where it is burned to produce electricity, which is exported to the National Grid.
- The generator is not part of the permitted facility and is owned and operated by a separated company (ENER-G)
- Maintenance work on the wells, including refurbishment and/or replacement of tubing and components
The permit application does not include hydraulic fracturing, drilling further wells or flow testing. Acid flushing and scale inhibitors or other chemical descalers are not used in well operations at Doe Green, the application stated.
INEOS has identified what it called “potentially sensitive receptors” near Doe Green:
- Surface water 3m and 85m from the site, which drains to the Penketh Brook, a tributary of the Mersey
- Farms and homes about 250m from the site on the A5080 and Sandy Lane
- Residential areas of Lingley Green (820m) and Penketh (812m)
- Railway 19m away
- White Moss Nursery and Garden Centre (480m)
According to INEOS, impacts on them may include:
- Particulate matter and dust
- Mud on roads
- Noise and vibration
The company said:
“Suitable design and operational measures will be provided at all times, to remove the risks altogether or mitigate them to ensure that there will be no unacceptable impact on the environment or human health.”
The application says there have been no potentially polluting major spillages at the site. A 1mm impermeable membrane was installed when the site was constructed and covered with 300mm of hardcore. It has not been uncovered. According to the application, “it is assumed that the membrane is fit for purpose and has not lost integrity as an impermeable barrier”.
Surface water collects in a drain around the boundary of the site. The application said there were currently no discharges to nearby rivers or streams.
It said the risk of groundwater pollution was negligible because:
- Any liquids pumped in to wells are not expected to propagate upwards through fractures within the coal seam but it said sub-surface leaks may lead to emissions of fluids into the coal seam
- The only fluids that are to be used within coal bed methane operations are process water and spacer fluid upon abandonment of a well. These fluids will not cause pollution
- Emissions to groundwater, surface water or soil as a result of surface spillages or leaks will be prevented through the maintenance of the design measures
- Site drainage can be isolated and water disposed offsite
The application says there has been no site investigation of soil or groundwater. It said:
“As there is a need to protect the integrity of the membrane, sampling would puncture it”.
- Workover waste from the well, including scale and scrap metal
- Waste from well abandonment, including concrete, spacer fluid and scrap metal
- Non-extractive wastes, including office/canteen waste,
- lubricating oils and greases, diesel, sewage, dirty and surface water
Venting and gas releases
The application said:
“Small volumes of gas will be cold vented during site maintenance activities. Gas will also be cold vented for pressure relief if required.”
But it also said:
“Measures will be taken to minimise all fugitive emissions which may cause odours.”
“In the event of any unexpected gas releases the Environment Agency will be notified. Details of the quantities of any gas releases will be recorded, where measurable, along with the measures taken to manage them and made available to the Environment Agency on request.”