2 Background |
What is unconventional gas?
5. "Unconventional" gas is still "natural"
gas, composed, like North Sea gas and other "natural"
gas" mostly of methane. Cuadrilla's CEO, Mark Miller, explained
that the term "unconventional" refers "to the type
of reservoir [not the technology used] [
] the techniques
are the same as you would use for a 'conventional' well",
adding that the technology "is used in the entire [oil and
gas] industry, not just in shale gas".
"Unconventional" is an "industry term coined years
ago to describe the type of reservoir, it is not the process".
Jonathan Craig, Fellow of the Geological Society of London, described
"unconventional gas" to us as an "additional [
not a new resource".
The Minister of State for Energy, Charles Hendry, told us that
shale gas "is [extracted from] a new [type of] strata, but
using an existing technology [
] it is a new application
for an old technology".
6. There are three main types of unconventional
gas: shale gas; tight gas; and coal-bed methane. Shale gas deposits
are trapped within shale rocks. Usually the shale rock is both
the source of the gas and the means of trapping it. Shale gas
resources are referred to as "plays" rather than fields
and they generally cover large geographical areas. Both shale
and tight gas are dispersed over much wider areas than conventional
gas, meaning many more wells need to be drilled to extract the
same amount of gas as from conventional resources. "Thermogenic"
shale gas is formed at depth under the influence of heatthe
gas is often "wet", meaning the methane is mixed with
other gases. In comparison, "biogenic" shale gas is
formed by the action of bacteria at shallow depths, and is usually
"dry" (which means that it is mostly methane)these
shallow resources can also overlie conventional oil and gas reservoirs.
Professor Richard Selley of Imperial College London told us: "Shale
gas has been produced since 1821 [...] the renaissance of shale
gas has been [driven by] an increase in energy prices in the States
obviously, but also technology".
He added that "The [
] properties of shale vary from
rock formation and from place to place",
which could be better understood if further geological research
into shale gas was funded.
7. "Tight gas" refers to gas deposits
found in low permeability rock formationsthis means the
pores in the rock are connected poorly. In order to extract the
gas the rock must be fractured to allow the gas to flow. The International
Energy Agency (IEA) definition of tight gas is based upon a gas
reservoir that cannot be developed by vertically drilling because
of the lack of natural flow.
8. Coal-bed methane, also known as "coal-seam
gas", is natural gas contained in coal-beds. Professor Selley
told us that there "is quite a long track record of coal-bed
methane extraction abroad and in this country",
to which Nigel Smith, of the British Geological Society, added
"there is a problem with CBM in the UK and Europe compared
to America [...] we do not know why [...] probably the permeability
of the coals are much lower in Europe and for the UK".
The "quiet revolution"
in Shale Gas
9. While geologists have been aware for many
years that natural gas deposits existed in shale formations, it
is only in the last 12 years in the US that the rate of shale
gas production has increased dramatically. This "quiet revolution"as
BP's ex-CEO Tony Hayward described ithas been facilitated
by the combination of "hydraulic fracturing" and horizontal
drilling. After drilling
down vertically to above the shale formation, the drill is steered
until the bore becomes horizontal and straight drilling resumes.
Most fossil fuel reservoirs are much wider than they are tall,
so horizontal drilling exposes significantly more reservoir to
the well bore. Hydraulic fracturing, commonly referred to as "fracing"
or "fracking" [both pronounced with a hard "k"
sound], is the process of creating fissures, or fractures, in
underground formations to allow natural gas to flow. The pressure
to create these fractures is generated by the injection of a fluidknown
as hydraulic fracturing fluiddown the well and into the
shale gas formation. Water and sand comprise around 99% of the
hydraulic fracturing fluid, the remainder being a mixture of chemicals.
The newly created fractures are "propped" open by the
sand, which allows the natural gas to flow into the wellbore and
be collected at the surface.
10. The techniques used to harvest these gases
have raised concerns about the potential environmental impacts.
These concerns are both about the above ground infrastructure
required and its visible impact, and also about the invisible
and possibly unknown effects of fracking. But the Minister of
State for Energy, Charles Hendry MP, told us that "horizontal
drilling has been something that we have seen in this country
and the North Sea for many years".
IGas Energy's CEO Andrew Austin told us that "these techniques
[hydraulic fracturing and horizontal drilling] have been used
elsewhere for many years, both onshore and offshore, with a strong
safety and environmental record in the UK".
Professor Selley told us that in recent years the "technique
] has improved in leaps and bounds in terms of the drilling
mud systems, the fracturing techniques [...] the drilling techniques
[...] the number of wells that you can drill off a single pad,
so you are minimising the environmental impact: you can get now
up to 16 wells off a single pad".
UK Onshore Drilling
11. Trying to put the issue of onshore drilling
in perspective, Professor Selley told us that there "is a
line of oil and gas fields around the Weald [...] There are fields
there that have been producing [conventional] oil and gas for
100 years [...] there was an oil field at Formby [...] BP have
done a brilliant job at Wytch Farm".
Wytch Farm in Dorset is the "the largest onshore oil field
in Western Europe"; the Geological Society cite it as a demonstration
that the industry can "successfully exploit resources [
while meeting the highest environmental and social standards".
Wytch Farm oil field was discovered by British Gas in the 1970s,
and has been operated by BP since 1984. The Geological Society
stated that "BP has set world standards in environmental
protection and community engagement, using horizontal drilling
at distances of more than 10km, keeping the size of well sites
] to a minimum".
12. The concern about the impact of more widespread
use of hydraulic fracturing has produced political reactions.
One of the principal concerns has been about the impact of the
chemicals added to the hydraulic fracturing fluid, particularly
on underground water aquifers. In May 2010, the Pennsylvania state
legislature passed the Marcellus Shale Bill that enforced a three-year
moratorium on further leasing of exploration acreage until a comprehensive
environmental impact assessment has been carried out.
On 3 August 2010 New York State issued a temporary moratorium
on new shale gas activity. This moratorium suspended the issuing
of "new permits for horizontal drilling which utilizes the
practice of hydraulic fracturing in the state" until after
the US Environmental Protection Agency (EPA) has reported on its
study of shale gas.
This EPA study is into the potential impacts of hydraulic fracturing
on drinking water, and is due to publish preliminary findings
in 2012. It is interesting
to note that Cuadrilla (exploring for shale gas near Blackpool)
intend to undertake exploratory hydraulic fracturing in combination
with vertical drilling, rather than horizontal drilling, so a
New York-style moratorium would not apply to their activities.
13. At the US federal level, on 9 and 10 June
2010 two identical bills named the Fracturing Responsibility and
Awareness of Chemicals (FRAC ACT) were introduced in both the
US House of Representatives (HR2766) and Senate (S1215). These
bills were proposed in the previous session of Congress and never
14. In response to our call for evidence, WWF
stated that it did not believe that shale gas production should
be allowed to take place in the UK. At the very least it considered
that "no permits should be granted for shale gas activity
[...] until there is a robust scientific consensus demonstrating
exactly what the risks are".
The Tyndall Centre thought that issues relating to local pollution
"leaves little doubt that in the absence of a much improved
understanding of the extraction process shale gas should not be
exploited within the UK".
On 26 January 2011 the Labour Party called for a temporary halt
to drilling for shale gas while its safety is checked.
15. On 2 February 2011, French Minister for Ecology
Nathalie Kosciusko-Morizet announced that France would be conducting
an assessment of shale gas's environmental impact. The French
Environment Minister added that no authorisation for work on shale
gas would be given before the outcome of this mission.
16. On the other hand, Jonathan Craiga
Fellow of the Geological Society of Londontold us "the
fracing of wells has been going on traditionally since the 1950s
] the first well that was fraced ever in the world was
] in the 1820s".
He added that "having bad cement jobs on your wells"
can result in contamination of local water aquifers, "but
that is exactly the same in conventional hydrocarbon exploration
] the fracs themselves are not the cause of contamination".
Tony Grayling of the Environment Agency told us the Agency would
not advise the Government that a moratorium was "necessary
on the grounds of environmental risks as we understand them at
17. Mitigation of the risk to water aquifers
from hydraulic fracturing relies on companies undertaking the
proper measures to protect the environment from pollution. However,
there is no evidence that the hydraulic fracturing process itself
poses a direct risk to underground water aquifers. That hypothetical
and unproven risk must be balanced against the energy security
benefits that shale gas could provide to the UK. We conclude that,
on balance, a moratorium in the UK is not justified or necessary
at present. But evidence must continue to be collected and assessed.
We recommend that the Department of Energy and Climate Change
monitor current drilling activity in the Bowland Shale formation
extremely closely during its early stages in order both to assess
the likely environmental impact of large scale shale gas extraction
in the UK and also to promote public confidence in the regulation
of the activity.
7 Q 124 Back
Q 161 Back
Q 185 Back
Q 283 Back
Q 3 Back
Q 70 Back
Q 68 Back
International Energy Agency, World Energy Outlook 2009 , p
Q 60 Back
Q 61 Back
Tony Hayward, The Role of Gas in the Future of Energy,
8 October 2009, www.bp.com Back
Q 281 Back
Q 161 Back
Q 4 Back
Qq 26-27 Back
"Pennsylvania lawmakers say bill that halts drilling in Marcellus
Shale aims to protect forest", Pennsylvania Live,
28 March 2010, www.pennlive.com Back
Bill A10490A-2009, State of New York, April 2010 Back
US EPA, Draft to Study the Potential Impacts of Hydraulic Fracturing
on Drinking Water, February 2011 Back
Ev 78 (Cuadrilla) Back
S. 1215: Fracturing Responsibility and Awareness of Chemicals
(FRAC) Act, US Senate, June 2009, www.govtrack.us/congress/bill.xpd?bill=s111-1215 Back
Ev 100 (WWF) Back
Ev 86 (Tyndall) Back
"The Labour Party calls for shale gas drilling halt",
BBC News Online, 26 January 2011 Back
"French Ministers Addresses Shale and Environment",
BBC News Online, 4 February 2011 Back
Q 198 Back
Q 198 Back
Q 240 Back