A month-long public consultation began today on regulation of Cuadrilla’s plans to test its exploratory oil well at Balcombe in West Sussex.
The company is applying to the Environment Agency to make changes to its permit for the well, drilled during anti-fracking protests in July and August 2013.
The application, running to nearly 100 pages, includes details of how the company will test the rate that oil flows. This will help to establish whether the well would be commercially viable.
As part of the test, the company said it planned to pump a 10% solution of hydrochloric acid round the well to clean the bore and the rocks surrounding it. There were no plans for hydraulic or acid fracturing, it said.
Cuadrilla estimated the tests could produce up to 35,000m3 of waste gas, which would be burned in a 45ft (13.7m) high flare. The tests were also expected to result in 82m3 of spent dilute hydrochloric acid and produced water from the well, which would be removed by tanker.
The application includes information about a new flare and monitoring arrangements for air and water quality during the well test. But some details have been removed from the application under a confidentiality option open to the company.
There is also a request to remove two waste products from the permit: drilling mud and spent acid and produced water, referred to as “salty water”. The company said it had “no intention to leave any fluid in the formation”.
The Balcombe well has been suspended since September 2013. West Sussex County Council granted planning permission in May 2014 for flow testing, abandonment and restoration. To comply with this permission, Cuadrilla must begin work by 2 May 2017 and complete operations within six months.
Kathryn McWhirter, of the No Fracking in Balcombe Society, said:
“We believe Cuadrilla are simply tidying up their paperwork before probably applying for an extension to their planning permission, and then we expect them to sell on the licence (PEDL) to another operator, probably UKOG.
“They say the impact of emissions from their new flare will be minimal. We disagree. The flare is one of the most concerning aspects of this development for the village.
“They have made a few feeble additions to their monitoring proposals, which remain totally inadequate.
“They seem to want to remove the ‘salt water’ flowback and produced water from the scrutiny it deserves under the minerals waste permit. We believe this waste should be carefully monitored.”
DrillOrDrop asked Cuadrilla when it planned to begin flow testing at Balcombe. This post will be updated with any response.
The deadline for comments is 25 April 2017. Link to consultation page.
The following information (except where indicated) has been extracted from the permit application.
Duration of flow test
3-7 days followed by 10-20 days of shut-in of the well
Flow test stages
Stage 1: Fluid currently in the well would be removed to a tank.
Stage 2: Approx 20m3 of 10% dilution of hydrochloric acid would be circulated in the well in a matrix acid wash. This would remove drilling mud debris from the horizontal section of the wellbore and clean the rocks surround it, the document said. It added that there would be “minimal” penetration of acid into the surrounding rocks – estimated at less than 6 inches – and the pressure used in the operation would not cause fractures.
Stage 3: Well flushed with nitrogen gas to remove liquids.
The company’s planning application said fluids and gases would then pumped from the well for about a week, 24-hours a day. Fluids would be stored in tanks and gases piped to the flare.
Flare and waste gases
The document said:
“This is an oil exploratory operation and we do not expect to encounter gas (although the possibility cannot be ruled out entirely)”.
However, it estimates, as a worst-case scenario, the volume of surplus gas from the well would be 35,000m3 for the duration of the well test.
Cuadrilla said it had developed a flare that would burn these gases at 800 degrees C, converting 98% of methane to carbon dioxide, carbon monomers and waste. If this standard were not achieved, the well would be temporarily shut-in to prevent the flow of gases, it said.
The application added:
“unabated releases of natural gas to atmosphere will be avoided”.
According to the document, the flare has a 15ft high stand pipe and a 30ft high chimney. Air vents had been cut into the chimney. This allows air to be drawn into system during flaring for a more complete burning of gas.
“The chimney suppresses both the noise levels and the light emissions. It also significantly reduces the heat given off by the flame.”
“All gas is trapped in the 30ft chimney and is subjected to a longer burn path, thus preventing any stray natural gas from escaping off to the sides before reaching the flame.”
Before the flow test begins, Cuadrilla said the flare would be hard-engineered to restrict it burning more than 10 tonnes of gas a day. The company would also carry out a review to ensure that it met Best Available Techniques.
- Well suspension fluid: assessed as hazardous because of the potential presence of crude oil
- Cement: assessed as non-hazardous; estimated volume 10m3; sent for off-site recycling
- Nitrogen: assessed as inert and to be vented from the well
- Spent hydrochloric acid and produced water: assessed as non-hazardous; estimated volume 82m3; sent by tanker off-site for recycling
Risks and monitoring
A risk assessment in the application concluded there would be:
“No significant risk from mud, odour, noise/vibration, waste, air quality and emissions with global warming potential, or accidents at the site”.
It identified measures to reduce risks. These included:
- “Use of Environment Agency authorised haulage/delivery companies”
- “Visual inspection of tanks during site daily HSE tours”
- “Wellhead, pipes and flare stack designed to prevent fugitive gas emissions”
- “24-hour supervision of pipes and flare during flow testing”
- “Flare designed for complete combustion at temperature in line with BAT [Best Available Techniques] requirements”
- “Ability to shut in the well in the unlikely event of an inefficient burn”
- Temperature monitoring and recording of flare at base and tip. Continuous monitoring
- Testing of pipework and joints before flow testing
Ground and surface water
The risk to ground and surface water was regarded as low. But the application said metals, hydrocarbons and dissolved methane, carbon dioxide and oxygen would be monitored onsite “to maintain surveillance on groundwater quality”. Metals and hydrocarbons would be monitored onsite for the impact on surface water quality.
Three single samples would be taken at the start, middle and final day of the well test for ground and surface water monitoring.
Air quality and emissions
The application said air quality would be monitored during the well testing programme, with checks at four locations for nitrogen dioxide, sulphur dioxide, hydrogen sulphide, methane, VOCs (volatile organic carbons) and BTEX (benzene, toluene, ethylbenzene and xylene – compounds in crude oil).
Fugitive air emissions were expected to be “very minor” and a low environmental risk. Methane would be monitored twice during the well test.
Noise and vibration
The documents said noise would be maintained at the levels set in the planning permission. The maximum levels were: 55dB from 7am-7pm Monday to Friday and 8am-1pm on Saturday; background levels 7pm-10pm; and 42dB at night (10pm-7am).
Flaring was likely to be a source of noise, the document said. But it said flaring would last for about a week, would not be near homes and the site was screened by trees. Noise monitoring would be “undertaken at pre-determined locations and close to sensitive receptors”. Complaints would be investigated and monitoring may lead to additional mitigation, the document said.
According to the document, the risk of spills was low. But nearby water features would be sampled once a week to identify any contaminants from the site. The quantity of produced water and spent hydrochloric acid would be recorded and sampled. The operations were not expected to produce smells.
The junction of the site entrance and the road would be inspected daily to “ensure potential mud deposits from road tankers does not become a problem”.