Geologist’s Submission to CWaC KW.22.7.14

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Submission to the Cheshire West and Cheshire Council working group on unconventional gas: Kevin Walsh 22nd July 2014.

I am a geology graduate (MA, Oxford) with long experience of academic geology and experience of the mining industry. I was lecturer at the University of Zimbabwe in the 1990s where I taught up to M.Sc. level. I have good knowledge of the geology of the Cheshire area, having lived in and around Halton since 1979.

Unconventional Gas

Gas may be recovered from three main unconventional sources: coalbed methane, shale gas and by the process of underground coal gasification.

Deposits of coal lying many hundreds of metres below ground are being explored as sources of coal bed methane. This is methane gas that is trapped within the coal, but which can leak out. In coal mines it is a serious risk to miners and continues to claim many lives, especially in China (Thomas, 2012). Methane from deep coal beds was initially thought to be uneconomic in Britain due to its low permeability. “The coalfield areas of the UK vary in rank, in confining pressure, and in gas content; this, with low coal seam permeability, will constrain CBM production in many parts of the UK” (Peters, 2012, after Creedy, 1999).

The first productive coal bed methane well in Britain was in Scotland, at Airth (Bacon, 1995, Department for Energy and Climate Change, 2010). Because of the low permeability it was necessary to hydrofracture (‘frack’) the coal bed. “Permeability (imparted mainly by the cleat) is necessary to achieve virgin coalbed methane production. The permeability of coal seams is low, so coalbed methane wells are normally stimulated to improve connectivity between the borehole and the cleat system. The coal seams may be hydrofractured, or they may be cavitated. Hydrofracturing is the method of well stimulation used to date in the UK” (Jones et al., 2004).

At the Airth well gas production began at 60 mcfd (January 1994), fell as low as 6 mcfd and reached 35 mcfd in 1995 (Bacon 1995). By comparison Island Gas and Nexen’s Doe Green 2 well, near Warrington has been producing gas at 45 mcfd. Coal bed methane wells take up to a year to dewater and then production may last for a few years at most, so these British pilot projects are typical of the industry at large.

About half of Cheshire is not in an area identified as having high coalbed methane potential (Department for Energy and Climate Change, 2010). Areas of Cheshire are being explored for shale gas, and a project to gasify underground coal has been proposed for beneath the Dee estuary.

The threat of climate change

The world is facing a major threat because of the increase in carbon dioxide in the atmosphere. This increase is due to the burning of fossil fuels (coal, oil and gas). Increasing carbon dioxide causes climate change and there are effects already with an increase in extreme weather events, a warming of the oceans, loss of the polar ice caps, increasing drought in some areas but flooding in others (including England), species loss and increasing ocean acidification.

The Intergovernmental Panel on Climate change (IPCC) is a body consisting of the world’s leading environmental scientists and is the internationally accepted authority on climate change. In 2007 they published a report (IPCC AR4 WG2.2007), on the impacts, adaptation and vulnerability of the planet to climate change. If the current use of fossil fuels continues unabated there could be severe impacts on human and animal life. “As global average temperature exceeds 4°C above pre-industrial levels, model projections suggest significant extinctions (40-70% species assessed) around the globe” (Assessment Report, page 242). Obviously this scenario cannot be allowed to happen and mitigation processes must be put into action. In 2014 the IPCC published recommendations on what these may be. In the majority of low-stabilization scenarios, the share of low-carbon electricity supply (comprising renewable energy (RE), nuclear and CCS) increases from the current share worldwide of approximately 30 % to more than 80 % by 2050, and fossil fuel power generation without CCS is phased out almost entirely by 2100.

The Climate Change Act (2008) commits Britain to a 26% decrease in the greenhouse gases by 2020 and by at least 80% by 2050. In the light of these targets and commitments there is no justification for exploring for a new source of hydrocarbon fossil fuel.


The Environment Agency published a guide to risks in shale gas exploration (Environment Agency, 2013). It can be assumed that similar risks exist for coal bed methane prospects. Their assessments as to the magnitude of risk in the process are as follows:

Overall environmental risks from shale gas exploratory operations


·         Materials released during site preparation


·         Loss of fracturing fluid


·         Water acquisition


·         Use of proprietary chemicals


·         Proppant delivery and mixing


·         Fugitive releases of methane


·         Disturbances of in situ substances


·         Drill cuttings and drilling muds


·         High volume hydraulic fracturing


·         Propagation of fractures beyond the target zone


·         Leakage from the borehole


·         Management of flowback fluids


·         Surface spills of flowback fluids


·         Build-up of naturally occurring radioactive material (NORM)


·         Onsite treatment of flowback fluids


·         Accumulation of solids containing NORM


·         Fugitive releases of methane and other gases


·         Controlled venting of gases


·         Exhaust emissions from onsite equipment


·         Offsite disposal


·         Transport, storage, treatment and disposal of wastes


·         Well closure and abandonment


The Concerned Health Professionals of New York (2014) published a compendium of the risks associated with the unconventional gas industry. This shows the numerous health and environmental dangers, and is well-referenced. The latest British body to oppose the industry is the Chartered Institute of Public Health (2014).

Water Resources

Cheshire is underlain by the Sherwood Sandstone formation, which provides groundwater locally and indeed contributes 25% to England’s total groundwater (Griffiths et al., 2002). It is an aquifer of type ‘Principal’. This is a type that is important as a source of groundwater or supplier of fresh water to river systems, and strategically important (Environment Agency, 2014). Aquifers can be polluted by agricultural, urban and industrial processes (e.g., Whitehead et al., 1999). Hydrocarbon wells leak (Davies et al., 2014). In USA and Australia this has led to methane in groundwater (Concerned Health Professionals of New York, 2014)

Air and Water Pollution

Methane contamination of groundwater has been a common occurrence in the American on-shore shale gas industry. In 2008 in Dimock, Pennsylvania, domestic water supplies turned brown or orange, smelt sulphurous, and in one case methane from the water caused an explosion. There were also adverse health effects in humans and animals (Prud’homme, 2014).

Air quality around unconventional gas wells has been found to be poor. The air around wells of rural western Colorado, USA was found to contain 44 volatile organic compounds (Colborn et al., 2014). These chemicals were found to affect the brain/nervous system, 33 the liver/metabolism, and 30 the endocrine system, which includes reproductive and developmental effects. (Concerned Health Professionals of New York, 2014).

The implications for public health from water and air pollution have led to questions on the safety of the unconventional gas industry at this time (Kovats, 2014; Mobbs, 2014).

Fugitive Methane

Methane may escape during and after gas production at a well (Armstrong et al., 2009). Well casings frequently fail allowing gas escape, and in the USA the biggest source of methane leaks is abandoned wells (Davies et al., 2014). Methane that is not collected and utilised is known as fugitive methane. The International Energy Agency warned “Greenhouse-gas emissions must be minimized both at the point of production and throughout the natural gas supply chain. Improperly addressed threatens to curb, if not halt, the development of unconventional resources.” (International Energy Agency, 2012).

The decommissioning of a borehole is essential to ensure long-term protection of groundwater. This involves plugging the well (be it exploration or production) with cement, welding a cap in place and burying the head (Moore et al., 2014). It is essential planning authorities consider this from the outset. There is no detail in the proposals for decommissioning of the Cheshire exploratory wells. This should be at least to the Environment Agency (2012) standards, with specific backfill materials stated.


The Cheshire Basin is cut by numerous faults of varying dimensions (Chadwick, 1997). Faults will disrupt drilling operations and make directional or horizontal drilling difficult. The presence of numerous faults in the Lanark region of Scotland was the main factor in the opposition to coal bed methane exploitation by Professor David Smythe. He claims “Dart Energy does not seem to understand the geology sufficiently well. The area to be developed abounds in geological faults, and the rocks overlying the coal seams do not provide a sufficiently impermeable lid to prevent methane and fluids escaping up to the groundwater. In short, the environmental risks are great.” (Smythe 2013, 2014).


Coalbed methane and shale gas are new to this country and have not been economically exploited. The coal deposits are probably not permeable enough to exploit (Jones et al., 2004). Fracking associated with shale gas is associated with many environmental and health problems in USA and Australia (Prud’homme, 2014). The UK deposits are smaller and more difficult to work (Thomas, 2010). The large deposits of shale gas under the Weald are now thought to be both uneconomic and compositionally unsuitable for working (Andrews, 2014). At present after a few years of profit it is now uneconomic to exploit shale gas in America. Bloomberg reported it now costs $1.50 to get out $1 worth of gas.

The problem of waste fluids

Coal bed methane waste water is extremely salty and has been found to contain not only harmful chemicals from the drilling fluids used, but also highly toxic BTEX (benzene, toluene, ethylbenzene and xylenes) chemicals including known carcinogens, and naturally-occurring radioactive materials. Spills and leaks of drilling fluids can also contaminate agricultural land and harm livestock. (Friends of the Earth, 2014). The amount of produced water from a single coalbed methane well varies between 0.1 – 0.8 megalitres (ML) per day (National Toxins Network, 2013).

For shale gas exploitation the problems and volumes of generated waste are far higher, as exemplified by the dumping of millions of gallons of waste from the Prees Hall test frack (Green et al., 2014) into the Manchester Ship Canal at 243 times the safe limit for Radium.

Interference of the rural character of the area

To support a coalbed methane operation there will have to be movements of hundreds of heavy vehicles every week for each well. This would cause considerable disruption in a quiet rural area. Tankers to remove the waste water pumped out of the well would be constantly present, and there is no plan on what to do with millions of litres of toxic liquid waste. Vehicle movements per day for exploratory unconventional gas well pads are estimated at 14 to 51 a day (Department of Energy and Climate Change/AMEC, 2013).


Much of Cheshire is a pleasant English countryside which should not be disturbed by industrialisation for little if any financial gain. The geology makes the area unsuitable for the extraction of coalbed methane due to structural geological considerations and environmental problems associated with both exploration and the possibility of extraction. This is a time of serious risk for the planet and the extraction and burning of new sources of fossil fuels is foolish. I believe the risks outweight any potential benefits.


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Armstrong, J., Mendoza, C. and Gorody, A. (2009). Potential for Gas Migration Due to Coalbed Methane Development. Alberta Environment.

Bacon, M.J. (1995). Development and techniques used on the Airth 1 well in Scotland. In Planning for profit: Coalbed methane in the UK and Europe. Conference 30-31 March 1995, Selfridges Hotel, London.

Bailey, H.E., Glover, B.W., Holloway, S. and Young, S.R. (1995) Controls on coal bed methane prospectivity in Great Britain In: European Coal Geology (eds: M.K.G. Whately and D.A.Spears) Geol. Soc. Spec. Publ. 82, 251-265.

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July 10, 2014

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