Proppant Squeeze???

[Paul Nuttall]

From the telegraph

It was a battle environmentalists thought they had won years ago. But fracking – the controversial technology for extracting oil and gas by cracking underground rocks – is about to stage a comeback.

Not, however, under its old name. The F-word, as some refer to it, is banned.

The companies seeking planning permission and licences to crack open Britain’s oil and gas bearing rocks are now talking about “proppant squeeze”, “reservoir enhancement” or simply “stimulation”.

Whatever it is called, fracking, albeit of a gentler kind, is reappearing.

Rathlin Energy won a licence from the Environment Agency this year to drill and “stimulate” a gas field discovered near Hull.

The West Newton field, thought to hold up to eight billion cubic metres of gas, is expected to connect to the UK gas transmission system within a few years and boost Britain’s energy security.

First the company will have to pump thousands of cubic feet of water into its wells to split the rock apart sufficiently for gas to flow out. While the volumes of fluid and the pressures will all be reduced, critics argue this remains fracking in all but name.

Today, similar schemes are being considered around the UK – partly because data suggest that there is a lot more oil and gas under the UK than realised. Fracking in all its forms offers a way to reach it.

Onshore oil and gas is already big. Research by the industry’s trade body, UK Onshore Oil and Gas (UKOOG), shows the UK has 120 active sites and 250 operating wells, producing 20,000 to 25,000 barrels of oil equivalent per day.

What lies in store could be far greater. “There are estimated potential reserves of 1,329 trillion cubic feet of shale gas under central England,” says UKOOG. “That compares to the UK’s annual consumption of just over three trillion cubic feet.”

In other words, there could be enough gas under England to power the country for centuries.

However, whether it is sensible to target these reserves in the current climate is another question. With Ed Miliband, the Energy Secretary, planning a legal ban on fracking, and oil and gas companies facing the country’s toughest corporate taxes, the question remains: why push fracking now?

The short answer is money. Fracking has been the single most disruptive force in energy over the last 20 years – reversing global flows of oil and gas and the geopolitical power balances they fuel.

So far America has been the biggest beneficiary.

Before 2000, the US oil industry was in steady decline. The “easy” oil, mainly in porous sandstone, was largely exploited, leaving America increasingly reliant on Middle East imports.

Fracking’s expansion 26 years ago reversed those dynamics – allowing engineers to tap into the vast reserves of oil and gas locked up in America’s shale deposits.

Shale is a dense sedimentary rock that holds its oil and gas in tiny disconnected pores. Breaking that out requires someone to pump a high-pressure mix of water, sand, and chemicals into the rock to literally crack or fracture it. The resulting fissures become a pathway for the fuel to flow out.

Fracking was accompanied by horizontal drilling where engineers worked out how to drill into an oil or gas reserve and then turn the drill-bit sideways.

This meant they could follow an oil or gas-bearing layer of rock for miles, fracking all the way, to drain ever more of its oil and gas.

Such innovations have made the US the world’s greatest oil and gas producer. Last year it produced 13.6m barrels of oil a day – 13pc of global demand. Its gas output was 3.4 billion cubic metres, 20 times the UK’s needs.

That surge has powered the American economy for two decades. Today, Britain imports much of its oil and gas from America, meaning it too is dependent on the success of fracking.

Francis Egan once planned to repeat that economic miracle in the UK. His fracking firm, Cuadrilla, targeted the Bowland Shale stretching under northern England — a layer of gas-charged shale up to a kilometre thick.

ack then, in 2008, politicians were keen. Cuadrilla’s fracking approvals, overseen by Miliband in his first stint as energy secretary, were rubber-stamped, opening up the English countryside to drilling for gas.

“Cuadrilla drilled five shale gas wells in Lancashire,” says Egan. “We successfully fracked the shale in three of those wells and flowed very high‑quality natural gas back to surface.”

He says the British Geological Survey reported that the Bowland Shale could contain 1,300 trillion cubic feet of gas, which would be enough to meet UK demands for decades or even centuries.

“Our analysis suggested a modest national development could have delivered peak production approaching total UK household gas demand within a decade,” Egan says.

But Cuadrilla’s drilling came with a price – a rash of small earthquakes culminating in 2019 with a 2.9 magnitude quake that set thousands of homes quivering. An instant ban followed and fracking seemed to be dead.

Today, in its rebadged form as “stimulation”, the process has been toned down, allowing it to no longer be legally classed as fracking.

Geologists say it is not yet clear on if this watered down version will cause the earth to move. Proppant squeeze still cracks open underground rocks but not so much, says Brian Baptie, a seismologist with the British Geological Survey, with evidence suggesting this avoids tremors.

However, University of Edinburgh geologist and fracking specialist Prof Stuart Haszeldine says the process is little different to the old fracking.

“Proppant squeeze produces exactly the same effect of fracturing the rock for hydrocarbon production as one big injection of high volume fracking, but does it by using smaller volume fracking along the borehole. There clearly are risks of water contamination and of earthquake-triggering.”

Fracking quakes are, however, typically small – similar to those that regularly affected thousands of square miles of the UK when we had an active coal industry.

Some say we would soon get used to them. However, any discussion of fracking – regardless of the name – fires up environmental groups that demand a complete ban on the technology.

Lorraine Inglis, of Frack Free Sussex, says proppant squeeze and reservoir stimulation are “all forms of hydraulic fracturing”, adding: “It’s wordplay designed to mislead. The strategy is obvious: frack using different language and normalise it.

“The risk of earthquakes is real and hasn’t gone away. The UK moratorium exists because seismicity couldn’t be predicted, and that doesn’t change at lower volumes.”

Miliband is nowadays sympathetic to these concerns, having long ago abandoned his former support. He has instead pledged to reinforce the moratorium on high-pressure fracking with a legal ban, although is less definitive on whether stimulation or proppant squeeze are acceptable.

An Department for Energy spokesman said: “We intend to ban fracking for good and make Britain a clean energy superpower, to bring energy security, lower bills and protect current and future generations.”

Such discussions are political as well as technical. The data showing Britain potentially has enough shale gas to meet its needs for centuries will put fracking in all its forms at the heart of debates about energy security for years to come – including May’s local elections and the next general election.

Richard Tice, the energy spokesman for Reform UK, says his party would put such issues at the heart of its manifesto. “It is our patriotic duty to use this valuable vital resource. Leaving it in the ground whilst relying on imported energy is nothing shy of negligence.”

[David Newton]

Fracking should never have been defeated. It was stopped to appease ideologues who have spread lies about it. It's that simple.

[Nik_SpeakerToCats]

IIRC, is a bit more complicated...

Lancashire deep coal-mines were progressively abandoned due to the large number of 'minor' faults criss-crossing area.
Seam off-sets abounded, water ingress exasperated.

Aggravated by Mersey / Hull being 'hinge line' for post-glacial isostatic flexure.
Scotland going up, SE UK going down, latter especially noticeable around London / Thames Estuary,

Unlike in US where major gas-bearing strata are vast and /'mostly' monolithic, Lancashire bedrock resembles a tumble of alphabet blocks.
Here a small oil-field, there a small gas-field.
No 'wide' continuity.
Fracking joggled them unkindly...

Hopefully, the Hull-region venture will have more stability.