The UK could see up to one spill for every four large shale gas pads, according to researchers.
In the first study of its kind, the Researching Fracking in Europe (ReFine) consortium has predicted that for production pads with 10 lateral wells there could be one onsite spill for every 16 pads. When 40 laterals were developed on a single pad, the rate was estimated to increase to one spill for every four pads.
The researchers from Durham and Newcastle Universities also looked at the risk of spills during the transport of liquids to and from sites. They predicted there could be one road spill for every 19 pads.
The study concluded that strict controls would be “a necessity” to minimise the risk of leaks and spills from any future shale gas industry in the UK.
Flowback fluid is usually highly saline, sometimes five times the salinity of sea water. It can also contain heavy metals, fracking chemicals, naturally-occurring radioactive material and hydrocarbons. Spills of flowback water, produced water, fracking fluid and chemicals are potentially hazardous if they enter natural ecosystems.
Lead author Sarah Clancy, a PhD student at Durham University, said:
“There is currently no shale gas production within Europe, but exploration wells are underway and the public has expressed concerns about the effects on the environment including the potential for leaks to pollute land, surface water and groundwater.
“Given the highlighted risks of spills from shale gas operations, mitigation methods are a necessity.
“If a shale industry is to go forward in the UK, or across Europe, appropriate strategies need to be in place to minimise the risk of spills associated with well site activities and the transportation, handling, storage and disposal of hydraulic fracturing related fluids.”
The study, published yesterday in the journal, Science of the Total Environment, used data on reported onsite spills in the shale industry in Texas (1999-2015) and Colorado (2009-2015). The researchers suggested that the number of reported spills may be an under-estimate. Despite this spills in both states increased over the period of study.
The researchers said the most common cause was equipment failure, corrosion, what were described as “acts of God” and human error. In Colorado, a third of spills were spotted during site remediation and random site inspections.
The study said:
“It is important that regular site inspections are performed by an appropriately trained work force and where possible constant onsite monitoring is carried out.”
The researchers called for systematic equipment checks and regular site monitoring during operation and after abandonment to identify equipment failures.
Last week, the industry organisation, UK Onshore Oil and Gas restated its case that 400 UK shale gas sites would be built over the next 20 years (link here). This followed an unpublished Cabinet Office report which estimated 30-35 sites by 2022.
The researchers estimated that in the first two years of drilling, a well pad with 10 laterals would require at least 2,856 tanker movements, each with a potential capacity of 30,000 litres of liquid.
Using spill data from UK milk and oil tanker industries, they predicted that a shale industry would be likely to experience an incident on the roads for every 12 well pads developed and a road spill for every 19 well pads over the lifetime of a well.
The paper said:
“Our analysis shows that when tanker movements for a single 10-well pad with 10 laterals is concentrated over two years the likely annual number of spills is less than one.”
But it added:
“Our calculations show that the number of spills increases to 2-6 when 100 wells sites with 10 wells per pad with one lateral each is developed.”
Previous research into commercial road transport has shown that long journeys, driver fatigue, time pressures, and unsuitable roads, such as country lanes made worse by bad weather or heavy traffic, could contribute to accidents and spills.
The researchers recommended there should be regular vehicle inspections and maintenance; specialised training and instruction for drivers; and appropriate driving schedules and routes.
Most UK onshore oil and gas sites have traffic management plans which specify delivery routes and hours for heavy goods vehicles. But campaigners against the industry have identified breaches of these plans at sites across the country.
- The ReFine website says: “The consortium is primarily funded by Ineos, with contributions from the Natural Environment Research Council, Environment Agency and the EU.” It adds: “Although partly funded by the energy industry, ReFINE enforces strict governance and ethical procedures to ensure that funders have no control over the research that is undertaken or published”.