Fracking explained

What is Fracking?

I am asked this question everywhere I go – what is fracking – little wonder seeing how I talk about it 24/7. I know boring! But to me it isn’t boring. It is important to get the message out there; to inform anyone and everyone how fracking is a very dangerous industry. Fortunately, I have the perfect medium to disseminate this from. The local Frack Free group I am involved with have come together to go on the road, visiting villages and towns in East Yorkshire, delivering information and awareness, and I have had the privilege to get involved in creating the display boards. This blog is about one such display board – What is Fracking?

I am afraid fracking is a very complex technology so I will endeavour to keep it as simple as I can, reduce it to layman language, and before I begin it is important to understand I am not an expert on these matters. I have experience of the petroleum industry but this doesn’t extend to fracking. However, I have researched the industry in-depth, scouring industry and government source material, and the ever increasing volumes of peer-reviewed research, so I like to think I have the knowledge base to write this blog.

I will begin by making it clear the term fracking has become a panacea for anything and everything surrounding the method of petroleum extraction where water is used. This is somewhat understandable when the correct terminology is ‘hydraulic fracturing’ (water, fracking), a process that has been used commercially since the late 1940’s. For the wordsmiths out there, the term ‘fracking’ is slang for hydraulic fracturing, and according to Merriam-Webster dictionary it appeared first in print in the Oil & Gas Journal in 1953. The term is a shortening of fracturing, replacing ‘tur’ with a ‘K’ thus conforming with the word formation when a vowel precedes the letter ‘c’.

For us to move forward to the subject matter, we need a time-out for a short history lesson, HF (hydraulic fracturing) can be low volume (LVHF) and high volume (HVHF). The former, LVHF, was commercially introduced in 1947, and is often cited as giving gravitas to the claim fracking is a long established technology. However, HVHF is a new technology which has been in commercial use since 2005. HVHF is responsible for the boom in shale gas exploration and production. This blog is about the new technology that underpins the shale gas boom.

The difference between low and high volume hydraulic fracturing is LV is a process used to ‘stimulate’ the flows of producing wells, whereas HV involves a process of releasing gas trapped in microscopic spaces in the impermeable shale rock stratum.  Hydraulic fracturing releases the gas by bludgeoning the shale rock.  Another difference is, up until 2005 all wells were vertical (conventional) but with the advent of horizontal (or directional) drilling technology (unconventional) a new method of extraction was needed, and this is where HVHF comes in. Nevertheless, LVHF continues to be used to ‘stimulate’ the gas flows of unconventional wells. Finally, this analogy sums it up for me, the difference between LVHF and HVHF is like the difference between a biplane and a Jumbo Jet! So true. Apologies to whoever coined it, I have misplaced the reference,

High Volume Hydraulic Fracturing (HVHF)

This technique always relates to ‘horizontal’ drilling.

It requires approximately 5 million gallons of water, 150-250 tonnes of proppants (sand and ceramics) and 60-100 tonnes of chemicals per frack, with a horizontal reach of roughly 2,000m, although current technology allows for a 3,000m reach. These ingredients are generally termed ‘fracking fluid’.

The fluid mix, according to the science, improves the flow of the fluids when injected; the mix holds the proppants in suspension under the conditions of high pressure. The proppant is the vital ingredient in that the sand and ceramic granules hold open the fractures in the shale rock to both allow and improve gas recovery. The proppant granules are specially manufactured into homogenised shapes and sizes. The chemicals used in fracking fluid are gels, polymers, acids and additives (each fracking operator has their own formula). According to the industry and Environmental Agency the chemicals are non-hazardous, though you would be hard pushed to find anyone who would put their bare hands in it! The clue here is ‘acids’. Cuadrilla state they use polyacrylamide, a known carcinogenic substance. Polyacrylamide is found in most beauty cosmetics, it is the agent that allows for absorption into the skin, and in very low doses (0.05g per product) it is considered safe to use. The quantities and concentrations used in the fluid mix far exceed this limit.

How does fracking work?
A vertical well is drilled to the point where it turns horizontal. In Yorkshire, the Bowland Shale is found 3,000-3,500m below the surface, an example is Kirby Misperton 3,079m.  After drilling, both vertical and horizontal, the wellhead is cased in steel and cement.  The steel casing of the first section of pipeline is positioned at the furthest point on the horizontal plain. The whole horizontal plain is laid in sections with a line of perforated piping, with each individual perforation capped. The perforated caps are ‘exploded’ by electrical ignition (perforation gun) controlled on the surface prior to the injection of ‘slick’ (water and chemicals) pumped in at high pressure (8,000 to 15,000 psi) to fracture the shale rock.  It is important to point out not all of the fracking fluid is used all at once, instead it is used in stages – one section after another.

The initial slick is followed by fracking fluids, again injected at high pressure. The fluid is drained by pumping back to the surface (see Flowback) and that section plugged. This is repeated until all the sections on the horizontal have been fractured.  The well is drained and plugs separating each section are removed.  On a 3,000m horizontal there will be 40-50 sections.


Between 30%-60% of fracking fluid either ‘flows back’ (flowback) to the surface or is drained via pumping during the process of hydraulic fracturing (fracking). This equates to 1.5m to 3m gallons of waste water alone. However, what returns to the surface as flowback, is the original fracking fluid mix and what is termed ‘produced water’. Produced water contains depositories and contaminants that have been trapped below the surface for millions of years, such as heavy metals (cadium, arsenic), carboniferous elements (benzene, toluene), NORM – naturally occurring radioactive materials ie radium – albeit in greater volumes, and greenhouse gases (methane and ethane). The levels of radiation, toxins and contaminants in produced water depend on the properties of the shale rock, and are generally considered to be extremely hazardous, to the extent the Environmental Agency have categorised this waste as ‘radioactive’ material.

The problem with produced water is that it is absorbed into the flowback to the extent every molecule of water holds the hazardous elements. This makes water treatment of flowback highly problematic. In fact, current technology can only separate and flush 85% of the toxins and contaminants, and because the other 15% is absorbed into the water it results in ALL flowback being discharged into waterways that run out to sea, in the hope dilution will minimise the hazard.

Gas flows

Unlike conventional petroleum excavation, where a well is situated over a naturally flowing oil or gas reservoir, shale gas needs to be released from shale rock using the techniques explained above. However, this technique is both crude and inefficient, in that it only releases a small proportion of gas, with exposed or fractured fissures having a finite gas flow. Therefore, and this is a well-known industry standard, easily obtained in plain sight from industry and government reports on fracking, output (gas flows) from each well declines by on average 70% within one year, and flat-lines to a very low flow after three years.  It is the sharpest of decline curves of all petroleum activities. Of course, there are exceptions to the rule, the odd well that has longer and higher flow rates, and others that exhaust very quickly, but these are few and far between. Therefore, the fracking operator has a decision to make, and this decision is based on economics; is the well worth the extra investment to restore it back to profitable output. If the answer is yes, then the well is ‘stimulated’ using LVHF techniques.

One might wonder why the fracking operator doesn’t do another HVHF? The problem here is, to re-frack at high pressure would not reach or create further extensive fissures at the existing perforation points, and there is a concern over destabilising the horizontal plain. Also, and this is probably the first consideration by the fracking operator, it would be a very expensive operation, and why so many low-flow uneconomical wells tend to be mothballed by being capped-off with a view to returning to at a later date. Many of these are abandoned awaiting decommissioning.
Therefore, to maintain ‘profitable’ output, the fracking operator opts to drill another well and commence the HVHF process again. . .and again. . .and again, thus developing a ‘model’ of maintaining high flowing gas. Hence, the reason for 5-12 boreholes per well site, and a proliferation of well sites that will turn the rural landscape into a gas field, if Pennsylvania and Queensland are anything to go by.

This isn’t scaremongering because, according to Cuadrilla and Ineos, each PEDL area – approximately ten square kilometres – will have 8-12 well sites. East Yorkshire has 23 or so PEDL areas, with the potential for 276 well sites with 3,312 boreholes. There are inherent limits to how many well sites there will be per PEDL, for example, the current radius of a well is 6,000m, but not all well sites will be governed by this radius – a significant number will be 2,000-4,000m radius. Density of well sites will be determined by where the rich veins of shale rock lay. A consequence of drilling geometry is the complexity it brings and exponential increase in risks of below the surface tremors and disturbing existing geological fault-lines.  


During the exploratory phase of fracking, the initial footprint masks the dramatic change in the landscape of the production phase. On the surface, each well site will be the size of a football pitch, and as already explained, below the surface it is a different scenario. However, during the production phase, shale gas excavation requires infrastructure which imprints far greater on the landscape. In order to transmit shale gas to the national grid or to ‘clean’ for industrial use, the gas needs to be processed at a dehydration plant and compressor plant before arriving at the transmission plant where the gas is filtered. To get the shale gas to these plants requires a network of pipelines, generally standing above the surface due to the inherent short-term nature of the industry (relative to gas-flows). The infrastructure is situated near to a cluster of well sites, requiring the size of two football pitches and unquantifiable lengths of pipeline. Based on evidence from Pennsylvania, the ratio of well sites to infrastructure is 5:1.

In addition to well sites and infrastructure, the cumulative effect of each of these footprints has the effect of reifying large tracts of the landscape into an industrial zone. Underpinning this effect is high-volume and intensive industrial activity and impacts ie constant flows of HGV transport and congestion and gas venting (flaring), and a working cycle of 24/7.

Impacts of fracking

The impacts of a shale gas industry are manifold and depend on where your moral compass points. On the one hand, it is an energy source and the north of England appears to have vast quantities, albeit deep lying. The government view this industry as a means of economic growth (taxes and employment) and energy security (a natural replacement for the depleting North Sea gas reserves). But, on the other hand, robust evidence from wherever fracking has taken place reveal the travesties of this industry. These are not trivial travesties when you consider government and industry reports highlight the inherent risks and consequences of this industry, so much so it has led to unprecedented community benefits being offered by fracking companies, and one-off payments by the government out of a Shale Wealth Fund. Fracking poses very real risks to the water supply (contamination and depletion), earthquakes as fault-lines are disturbed, health impacts from fugitive emissions, and environmental consequences re climate change, but most of all how it will impact on the lives of those who live in idyllic surroundings, condemned to live in the gas fields.



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