Regulation

Residents “astounded” by decision which could lead to methane and benzene venting at fracking site

PNR 191022 Maxine Gill

Cuadrilla’s Preston New Road shale gas site near Blackpool, 22 October 2019. Photo: Maxine Gill

Cuadrilla has been given permission to use a technique at its Lancashire fracking site which could see the release of methane and other gases into the atmosphere.

The Environment Agency confirmed today that it had allowed the fifth change to the company’s environmental permit for the Preston New Road shale gas site.

The variation will allow the use of nitrogen lifting after fracking.

This technique brings liquids, such as fracking and formation fluids, to the surface of a well. But it can also stop methane and other gas being burned in a flare, which means they are vented instead.

Residents living near the site say they are “astounded” by the decision.

Until now, Cuadrilla’s permit has prevented the company from venting unburnt gases except for in an emergency. In May 2019, we reported that the company was found to have breached the permit by venting an estimated 2.7-6.8 tonnes of methane during nitrogen lifting.

Two months later, it applied to change the permit to use nitrogen lifting. It said the technique was needed to remove liquids in the well that prevented gas flowing to the surface during flow tests.

Today, the Environment Agency (EA) accepted that methane and other gases could now be released unburnt:

“The use of nitrogen, which is an inert gas, may result in the release of uncombusted formation natural gas (which is principally methane), known as venting.”

Opponents of the use of nitrogen lifting are concerned about the climate-damaging effect of releasing methane, a potent greenhouse gas, and the health impacts of emissions of other gases, such as benzene, a carcinogen.

A spokeswoman for the Preston New Road Action Group, a local campaign organisation, said today:

“As close residents of the PNR site we find it astounding that the EA have granted Cuadrilla permission to use nitrogen lift.

“They will now be able to cold vent climate-affecting methane and gases such as benzene, that are harmful to human health, into the air that we are breathing.

“Nitrogen Lift is a process usually used at the end of life of a well to extract the last bits of gas, yet Cuadrilla are going to be using it throughout the flow testing process.”

The EA said in a newsletter, also released today, that the level of vented methane would have “minimal environmental impact” and did not “represent a risk of harm to people”. It said there had been a rigorous technical assessment and modelling and there were controls on how long gases could be vented. Preston New Road Community Update 11-24 October 2019

Cuadrilla said on its website:

“Cuadrilla has undertaken a detailed Best Available Techniques (BAT) assessment to demonstrate that this technique is environmentally sound. A detailed air quality modelling and assessment exercise has concluded that no unacceptable impacts are predicted.  In granting the permit variation today, the Environment Agency has agreed with our assessments and our proposed approach.”

The decision appears to be at odds with the findings of a study for the Environment Agency, also published this week. This concluded that emissions from flares, including those on oil and gas sites, could be underestimated.

Details

Cuadrilla applied for the permit change a month before it began fracking the second well at Preston New Road, now suspended after a series of earth tremors.

There were 300 responses to a public consultation on the variation. The Environment Agency said in its decision document released this afternoon that nitrogen lifting and the existing flares at the site were considered to be the best available techniques. It described nitrogen lifting as “a safe and commonly practised technique in the oil and gas industry”.

The EA said benzene was the main likely air pollutant in venting at Preston New Road. Air quality modelling by Cuadrilla showed that emissions of benzene would be “well below the short-term environmental standard”, the EA said. Benzene venting would not cause significant pollution if carried out for no more than 30 days, the maximum allowed under the permit change, the EA added.

It said Cuadrilla would be required to analyse the gas going into the flare for the presence of benzene and to report on these emissions every 10 days, instead of the current requirement of every 28 days.

On concerns about climate change, the EA said:

“We are satisfied that the measures which are in place represent best available techniques which will ensure that no significant pollution will occur as a result of the use nitrogen lifting.”

On the recent tremors, the EA said:

“We are satisfied that the changes in this variation do not increase the potential for tremors.”

According to the decision document, Cuadrilla had considered alternatives to nitrogen lifting, such as swabbing, downhole pump, rod pumping and other gas lifting techniques, but had rejected them.

The EA said the company had proposed to use propane as a support fuel in its flare to reduce the amount of vented other gases:

“Where appropriate, propane will be used to increase the proportion of combustible gas (natural gas from the formation and propane support fuel) and bring forward the point where the gas mixture will ignite in the flare rather than being potentially vented to atmosphere.”

The EA It said the company would also be required to have a continuous video feed of the two flares are the site when they are in operation and keep a register of days where cold venting has been varied out.

The EA said Cuadrilla would also be required to monitor gas concentrations in liquids being directed to the flare.

Once methane reached 20% volume for volume (v/v), the company would use propane to do a supported ignition test, the EA said. If the flare did not ignite after five minutes, Cuadrilla would stop adding propane to prevent its unburnt release. Monitoring would continue and the supported ignition tests would be repeated at each 5% v/v increment until ignition was successful. This was likely to happen at methane concentrations of 30%-50%, the EA said.

  • People outside the Preston New Road site had reported black smoke and visible flames above the flare this month. In today’s newsletter, the EA said the smoke followed the addition of propane. It said it had carried out an audit, the results of which would be published online. The newsletter also said pools of water around the site at the end of September were surface water draining from the fields, not from the site.

Links

Decision document on permit variation

DrillOrDrop page on Preston New Road with key facts and timeline

Environment Agency Preston New Road web page

 

 

28 replies »

  1. “Nitrogen Lift is a process usually used at the end of life of a well to extract the last bits of gas, yet Cuadrilla are going to be using it throughout the flow testing process.” Why do people who nothing about a subject, insist on speaking about it.

  2. David I agree. Clearly it is difficult to educate people on N2
    Lifting. We have tried to explain N2 lifting several times on this BB but PNRAG (local residents) seem to have a mental block grasping the basic concepts and physics of what N2 lifting is used for. One more time – N2 is used to reduce the hydrostatic head to allow the well (reservoir) to unload fluids so that the hydrocarbons(in this case gas) can flow naturally using a positive pressure differential between the reservoir and the wellhead. ie the reservoir pressure is greater than the hydrostatic pressure exerted by the fluid in the well bore. Simply put, it won’t flow if full of water, remove the water with nitrogen and it will flow with a column of gas. It’s not rocket science….. And N2 is not used “to extract the last bits of gas” ; it may be used to lift water from a well if water influx had killed the well but that is all. N2 doesn’t combust, hence the propane. Surely locals would understand all this by now?

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