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Topic 50: Shale Gas Harmful or not, Economical or not

Trevor Strawbridge's picture

There is an ongoing debate about the dangers associated with drilling for shale gas. These are indicatively; the potential contamination of the water supply in rivers etc, caused by leakage during the Fracking process, the potential for surface leaks and the toxins that are associated and so on. Furthermore economists forcast low profitability along with high environmental, health & safety and economical risks. Some states in the US have banned or are in the process of considering banning the production of shale gas. So I would like to ask my fellow forum subscribers; should this be banned? is it safe? is it viable? The RFF has published a Risk matrix for the producers earlier this year. It doesn't appear to be straight forward to me but I may be misinterpreting it. As usual I appreciate any comments and look forward to hearing peoples views on this topic



Keqin Chen's picture


As an unconventional energy, shale gas has caused more and more
attention recently. Due to development of horizontal drilling and hydraulic
fracturing, the industry of shale gas has boomed and become profitable. In fracturing,
fluid which is composed of slurry of water, ceramic proppants &
chemical additives (0.5%) should be pumped into well bore at sufficient
pressure to create, propagate and maintain a fracture in the surrounding rock

In the production of shale gas, there will be two main risks caused by
the hydraulic fracturing listed below:


1. Earthquakes

United States Geological Survey
has shown the recent increase in the number of magnitude 3 and
greater earthquake in the midcontinent of the United States
where the production of shale gas emerges. It is believed that water pumped
back into the fault tends to cause earthquake by
slippage of fault. [1]


2. Troubles about water

Troubles related to water have been caused by
the hydraulic fracturing:

On one hand, the local drinking water supply in natural
aquifers can be affected by large quantities of water needed in the fracturing
of shale gas. And things will often be worse because the location of shale gas
accumulation will be shortage of water naturally.


On the other hand, there is potential risk of water
pollution for the introduction of large amount of water which contains chemicals.
And only about 50% to 70% of the resulting volume of contaminated water is
recovered above-ground, while remaining waste water from such operations stays
in the formation. [2]


So, the relationship of environment and shale
gas production has to be tackled carefully.


[1] Is the Recent Increase in Felt
Earthquakes in the Central U.S. Natural or
 United States Geological Survey,
11 April 2012


[2] What are the advantages and
disadvantages of shale gas?



Keqin Chen

Msc of Oil and Gas Engineering


Toby Stephen's picture

In terms of harm to the environment, concerns regarding shale fracking are identical to those of fracking any other reservoir (water consumption, groundwater contamination etc). There are, however, several techniques currently being devised to work around the need for fracking:

The 'Freeze Wall' technique devised by Shell uses a circular formation of wells in which a coolant is circulated at a specific depth to effectively create an impermeable frozen flow barrier and thus
prevent subsurface contamination (see Appendix A1). Within this perimeter wall, heater wells and a
production well are drilled, allowing the formation to be heated at the required depth interval in order
to thermally crack the oil shale into gas which then flows out of the production well. (1)

The AMSO ‘Conduction Convection Reflux’ (CCR) technique – two wells are horizontally drilled (a
heater well below a production well) in the shale formation and heated by a downhole burner. As the kerogen decomposes due to the
applied heat, the lighter materials rise and condense, distributing heat throughout the formation and
allowing the oil and gas to eventually escape through the production well. This is effectively a 'self-fracking' technique in a sense as the applied heat causes the refluxing oil to apply a compressive stress to the surrounding cooler shale. (1)

To answer your original question - if conventional fracking is still allowed to occur in the vast majority of the oil/gas producing world, I don't see why shale fracking shouldn't. It should be an 'all or nothing' approach as it would seem hypocritical otherwise, in my belief. Is it viable? This is much more difficult to answer - a lot of promising shale technologies are currently only in the pilot stages (ie AMSO CCR technique) so it remains to be seen whether a) it works at a lab/small field scale and b) whether it can be upscaled to a commercially successful level.



P., Burnham, A., Fowler, T., Herron, M., Kleinberg, R., & Symington, B.
(2011). Coaxing Oil from Shale
(Vol. 4). Pau: Oilfield Review.


Toby Stephen
MSc Oil & Gas Engineering

Trevor Strawbridge's picture

Two very interesting responses. There does seem to be one common factor that seems to induce the risk here and that is water. I dont disagree with Toby's response, where fracking is used in conventional drilling; and whilst I dont claim to be a drilling expert, I know that water injection is used conventionally to aid "lift" , but I dont know where else it would be used for fracturing. I may well be wrong. However, since the two main risks described by Keqin; which are contamination and geologically related, by using the high pressure water fracking technique, and since Toby has discribed alternative methods, Should the industry focus on these alternative methods and reduce or eliminate the risks. Maybe it could be safe and indeed viable.

Thanks for your comments guys



Toby Stephen's picture

In response to your next question regarding whether industry should focus on these alternative methods - the viability of shale needs to be better understood. History shows that much attention is diverted to shale energy on the back of spikes in oil price which is exactly what is happening at present. The main concern for me is the energy return on investment (EROI) which is very low for shale (most predictions vary from 2 to 8, with an EROI of 2 placing it in roughly the same category as tar sands in terms of labour intensity). I don't necessarily agree entirely with an article I found (1) but a good quote from it sums up shale energy as follows:

"Yes, there’s lots of low-grade oil shale in Colorado and Utah. But
there’s also enough Helium 3 on the moon to power the world for
thousands of years, and enough microscopic gold in the ocean to make
everyone rich. It’s theoretically possible to microwave solar energy to
Earth from outer space, and to transmit wind energy from the Aleutians
to Atlanta. Fusion has been just around the corner for fifty years.
Grandiose schemes to meet the world’s energy needs always find
articulate proponents.

 (1) Udall & Andrews (2005) - The Illusive Bonanza: Oil Shale in Colorado


Toby Stephen
MSc Oil & Gas Engineering

Kobina Gyan Budu's picture

While agreeing with Kevin on his second point concerning water treatment, it is worth noting that not all communities have
access to treated/portable water. Many of the rural folks may be using the water in its raw state and those are the more
However, hydraulic fracking and directional/horizontal drilling are not new and peculiar to shale gas, as they have been in
existence since the early nineteenth century.  They have been part of the key technologies that have propelled the oil and
gas industry for decades.
The fracking fluid consists of about 99.5% water and sand, and less than 1% of common chemicals in differing combinations
used to prevent bacteria growth, reduce friction, and perform other essential functions, such as keeping the sand suspended
in the solution. Many of these same chemicals about which the concerns have been raised are also used in household cleaning
products, cosmetics, and even food.
Many of the concerns are more of perception than reality. They are mostly coming from the public and policy makers who are
unfamiliar with these technologies. The risk of water and air pollution, earthquake etcetera which have become of great
concern can be mitigated if society finds value in shale gas. It is incumbent upon organisations to help improve the knowledge
base of policy makers and other pressure groups to be in sync with the technology. Open policies must be established with
government regulatory functionaries so together, the levels of the chemical used in the fracking process can be audited regularly.
Shale gas is not as harmful as perceived to be but rather economical and has to be tapped for societies’ development.

Kevin K. Waweru's picture

The twin issues of water quantities used for shale gas fracking and contamination of underground water as Trevor has highlighted may be classic examples of highly publicised misconceptions.

Prof Andrew Hurst reminded us at the strt of his lectures (Finding Oil: Geo-science in Exploration and Production) that hydrocarbons (oil) make up less than 1% of the Earth’s crust with water making up a much bigger share. The overall water quantities used for fracking can be said to be minimal compared to the bodies of water available on the planet. That reason only should compel us to stop worrying about the quantities of water used in shale gas fracking. Perhaps access to safe (treated) water for drinking is a global issue that warrants more concern but I stand to be corrected. This leads me to my second point.


The water we access for everyday use is first treated to a certain quality or standard before we use it in order to make it safe. The raw water is first sampled at its natural source and analysed to understand its chemical composition. It is at this stage that any contamination arising from the fracking activities would be detected and appropriate treatment implemented to make it safe for consumption.

Furthermore, the fracking process is said to occur deep below the underground water aquifers we rely on for our everyday water supplies hence posing very minimal risk.

Kevin K. Waweru

MSc Oil & Gas Engineering

Kobina Gyan Budu's picture

I find this an interesting debate and will want to add a voice. I share Kevin’s first point on the abundance of water on
the planet compared to the minimal amount used for hydraulic fracking. In addition, addressing Trevor’s point on economics,
I will disagree with the economists’ forecast. Firstly, the recent unlocking of shale gas has now changed the fortunes of
the United States giving them reserve life of more than 100 years at the current demand levels. This gives the US some comfort
in terms of energy security, a situation that was not foreseen just a few years ago.

Secondly, the discovery comes with it job creation and economic growth. A recent economic impact study found that the U.S.
natural gas industry as a whole accounts for 2.8 million jobs and contributed more than $380 billion to the U.S. economy in
a single year.

This can only reasonably be described as economical. Improvement on the technologies to reduce the comparatively minimal
negative impact is preferred to a ban.


Ikechukwu Onyegiri's picture

Interesting points raised up so far, the environmental damage that has been forecasted should there be a drastic paradigm shift to shale gas is not one to be neglected as previous comments have said but I want to highlight the absurdity of the current situation. Of course any ecological disaster must be prevented in every possible way. Man's eagerness to harness energy sources so as to create security is one that burns without relent. No doubt the potential risks to health and environment due to hydraulic fracturing is eminent but alao there is no evidence to the contrary that alternate solutions can't be developed. This is the same issue Total faced in the debate of shale gas exploration in France, who with 98% of their gas imported still applied strong propaganda without much real evidence of its effects on the environment.

The bone of contention is this, in view of the benefits which shale gas has got to offer energy-lagging economies such as: job creation, cost reduction in domestically-produced energy, energy security e.t.c. one must not forget the environmental and health hazards involved with its exploration and production, though I am not of the opinion that hydraulic fracturing should be stopped since we have been living with conventional fracking for a longer time and measures have been devised to handle some hydraulic fracturing concerns as Toby said.

Energy rules the world, only innovatitive minds can survive the future and balances have to be made. Prior to new technologies which could replace fracking of shale gas, its a dynamic player in world energy and economics today and can't be ruled out. It sure have an improving effect on economies and who knows what the future holds for energy demand and supply.




Ikechukwu Onyegiri

Msc Oil and Gas Engineering

A large number of water consumption is involved in the development of
shale gas which is determined by the technical characteristics for shale gas exploitation.
Hydraulic fracking technology is required to reach shale gas for it is bounded
by tight shale. The fracking liquid mainly include high pressure water, sand
and chemical additives among which the percentage of water and sand is above
99%. The number of wells will be large for shale gas development. According to
statistics, the average water consumption for each well is 15,000 cubic meters
so the exploitation of a shale gas field will use a great deal of water source.  To the areas which lack water resource, the
development of shale gas will deteriorate the water shortage situation.In the
meantime, it may lead to the change of climate. 
Although the carbon dioxide emission from shale gas combustion is less than
that of coal and petroleum, there exist other greenhouse gases escapes during
the process of exploitation, transportation and storage. So in the moment that
greenhouse effect is getting more and more severe, it should be more cautious
for people to exploit shale gas.


Hydraulic fracturing has a greater green house impact than coal and conventional oil and gas. the process of fracking to obtain shale gas leads to fugitive emissions of methane gas which is a potent greenhouse gas. According to a report on "Methane and the Greenhouse Gas Footprint of Natural Gas from Shale Formations", methane contributes to a large extent to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The fracking process has also been reported to contaminate water supplies of residents located near drill sites. The flow-back created during a fracking process involves a substantial amount of the already injected water returning to the surface. This water carries along large quantities of methane. At this point I would play a fair judge as to say there is no source of energy that doesn't have its bad side but i would personally recommend  that there should be a revision to carbon-trading markets that are currently under valuing green house warming effects of methane.

Okechukwu Chukelu (51231798)

sreehariprabhu's picture

 The most common method used to extract shale gas is by hydraulic fracturing. Hydraulic fracturing is the propagation of fractures in a rock layer as a result of an action of a pressurized fluid. The reason for hydraulic fracturing is that the rocks are not permeable. So for the flow to cause, this method must be used, which provides permeability. The main danger associated with shale gas recovery is that it can affect the environment. It leads to the leaking of extraction chemicals into the water, which contaminates the water. During extraction, it also leads to the leaking of greenhouse gases. Shale gas produced by hydraulic fracturing causes higher well-to-burner emissions than conventional gas. This is due to the gas released during the well completion as some gases return to the surface along with the fracturing fluids. 

 Shale gas emits a much harmful greenhouse gas Methane. During fracturing, chemicals are added to the water. Eventhough this water containing chemicals are taken back on land, more than 30% are left in water which makes the water polluted. Other danger related is that, a study has shown it also can lead to earthquakes.


Sreehari Ramachandra Prabhu

Tianchi You's picture

Since shale gas is a kind of unconventional gas, it has hugely potential value on the future. According to the data, it is estimated that there is apporximate 456,000 billion steres shale gas in the world; the main location is in North America, Central Asia, China, South America, Middle East, North Africa and Russia. Here, I will talk about some problems about shale gas.

  • Low abundance
  • The minable resource is low
  • Low porosity
  • Low permeability
  • It requires high-technology for exploring
  • High technology on well logging and well completion
  • Some countries use "fracking" to explore and improve the efficiency, we have discussed the hazards behind the fracking technology

The fracking may result in several serious issues such as pollute the water resevoir and the environment, foil the carbon capture covers(eg: in US 80% of potential CO2 is overlaped with shale gas field.), increase the probability of earthquake etc..

But as the energy demand is increasing everyday, we can not stop people exploring and exploiting the shale gas, in my opinion I think there may have several useful ways to low down the risk:

  • Put more investment on technology to find more ways to exploit the shale gas
  • Analyzing the data as soon as possible, connecting it with seismic data to improve the efficiency
  • Evacuating people whose residences are near the oil field
  • HSE needs to investigate the probability of the risk management that the oil company have made



Tianchi You


Oil&gas engineering

Dear Colleague,


Regarding the hydrofracturing do refer on my post at following link


In my opinion, the true issue on this matter would not only be on the environmental impact but also legislative matter.


In my opinion, the environmental aspects could be mitigate after tackling the legislative aspects. Shale gas should not be ban but to be regulated to answers and mitigate environmental impact [1]. In addition, land ownership and population residing atop of the reservoir are two issue that should be taken into consideration.


The environmental impact could be minimized as suggested in my other post as above mention link.


In conclusion, if we do it right, I do think shale gas would poise any environmental impacts. In addition, shale gas produced methane that has lower Green gas emission compare to oil and gas [2]. This in turn helps to reduce the CO2 footprint that the world has been chanting about.



1. Lewis, B. (12 November 2012). Shale gas need regulation not a ban: European Parliament. Reuters [Online] Available from :

[Accessed on 29 November 2012]


2. Johnson, P., (2012). Structuring the shale gas controversy: Issue. Environmental Justice Organisations, Liabilities and Trade project EU framework 7 Programme. [Online] Available from:

 [Accessed on 29 November 2012]

Alabi Ochu Abdulraheem's picture

Safety in Shale gas drilling
The safety associated with shale gas can be seen from its exploration point of view. Shale gas is a natural gas (containing

mainly methane) produced from shale formation. Recently the shale gas exploration has warranted the use of a combined

horizontal drilling and sequenced multi-stage hydraulic fracturing technologies. Though both technologies as different

advantages (better economics and higher permeability respectively) but faces different threats which includes: destruction

of the ecosystem, reduced landscape, vegetation loss, soil erosion etc. The safety of the exploration can only be spoken of

after the risk associated with all these threats have been adequately identified and analysed. After the risk has been

identified, then proper integrity management plan can be done to improve the safety of the technologies.
Daniel A. J. "Environmental consideration of modern shale gas Development" SPE 2009, New Orleans, louisiana, USA.

Name: Alabi Ochu Abdulraheem
Reg no: 51231595

Adejugba Olusola's picture

Quite a lot of issues associated with Shale gas exploration and Fracking were discussed under the Fracking topic. To my mind, all those issues and most of those mentioned above can be addressed and adequately managed to ensure minimal risk to people and safeguard the environment. The challenges associated with Shale gas are not insurmountable and with adequate risk management, technological advancement and effective legislation, they can be managed.

Technological advancement will play a big part in the cost of exploring shale gas and as Toby mentioned, Return on Investment is probably still too low for large scale production. However, with better understanding of fracking and more effective fracking methods, there may yet be an opportunity to harness this energy source. Oil & gas exploration took years to develop to the current levels and it is still benefitting from smarter and more effective methods of exploration so no reason why same will not be applicable to shale gas exploration.

Adding Shale gas as another source of energy to the diverse energy mix needed for the future will only bring benefit to an ever-increasing world population demanding for more energy.

Adejugba Olusola

Kii Cajetan Barisi's picture

Shale gas is being sold to the American public as a miracle, arriving just in time to save us from peak oil. It's an abundant new fuel supply that will be a "game-changer," we're told. We'll soon be a major exporter of gas to the rest of the world. The economics of fossil fuels have been changed forever, along with our balance of trade.

But what if the business isn't actually profitable? What if it's really based on accounting trickery and overstated claims?

"Fracking" - extracting natural gas by drilling horizontally through dense shale, then fracturing it with high-pressure fluids - has indeed given the U.S. a nice bump in gas production. Production of dry shale gas soared ten-fold from under 0.4 trillion cubic feet (tcf) in 2003, to 4.8 tcf in 2010. Total gas withdrawals, including conventional gas, are up 16 percent since the end of 2005. Shale gas now accounts for about one-quarter of total U.S. dry natural gas production, and about 4 percent of our total primary energy supply.

Our shale gas resources, however, while much ballyhooed in the press, are far less certain. We may now have a 100-year supply of gas in America, as suggested by recent reports. . . or we may not. The U.S. consumes 24 tcf of gas per year. Currently, we only have an 11-year supply on the books: 273 tcf classified as "proved reserves," meaning gas that is commercially producible at a 10 percent discount rate. Beyond that, there are only "probable," "possible," and "speculative" resources, where the gas has not yet actually been discovered, or proved to be economically recoverable. Even where we are sure that the resources exist, we do not know how much of is technically recoverable until we produce it. And as I noted two weeks ago, in the EIA's Low Case shale gas estimate, the U.S. could become a net gas importer by 2035.

There is no doubt that we are producing a lot of gas, for the moment. But it may have come at the cost of profitability.

American Gasland," artwork by River Side (marcellusprotest/Flickr) 

faizakhatri's picture

Shale gas having significant global value for future because it is easiest way to generate of electricity  with more cost-effective and more reliable way to reduce carbon dioxide emissions since it is  composed mainly by methane components which is although a part of GHG gases but not has a potential to harm for climate it can be extract from dense shale rock formation  according to a BBC story, we are told shale gas ‘worse than coal’ for climate in my opinion it is a cleaner burning than oil or coal a good  form of energy which produces lighter amount of GHG gases as compare to heavier hydrocarbon fuels such as coal and oil there are only two methods are available for extraction for shale gas hydraulic fracturing and horizontal drilling both are ways to making them economically recoverable but the main problem raising 

  • Contamination of ground water during fracking 
  • hydraulic fracturing fluid having some of hazardous chemicals which may leak,spills,or other pathways to surrounding areas 
  • Fracturing process can produces large amounts of waste water  contain dissolved chemicals and contaminants that require treatment before disposal or reuse because of large quantities of water is used during process so  treatment and disposal is an important and challenging issue

but still more innovation or technological advancement is needed in fracturing process 

Faiza khatri

M.Sc oil and Gas Engineering


Siwei Kang's picture

some of my
classmates mentioned that there are some negative things happened when shale
gas production is booming. Here I want to share my points of shale gas.

Firstly, the
hydrodualic fracking is banned in some states in USA, not the shale gas production.
I have not seen any regulation which forbidden the shale gas production in USA, even in France. Although  some issues
like water contamination, earthquake and greenhouse are rising in some regions
where the shale gas production is active, there is no documented evidence to
prove that fracking is the direct cause of issues despite the unpropriate operation during shale gas production. A study to
determine the total methane emission during the shale gas development is under
process by University
of Texas, and it is
expected to be finished next year. I believe that the shale gas production will
be more environmental friendly and safety with the advancement of technology.

Secondly, the
unconventional energy in USA
has already account for large proportion, around 26% of total annual gas
output in 2010. The EIA projects that the
unconventional gas share in USA
toal gas output in 2035 will be more than 70%, including 49% of shale
gas. Thanks to the advancement of horizontal drilling and fracking
technology, from 2007, the USA gas import from Canada has been reduced
conseductively in five years. It highly lower the energy dependence of

Finally, a mount of
large shale gas play has already been discovered and developed during
the past two decades. Except the Barnett and Haynesville Shale, the
Marcellus is under development. Its recoverable gas is around 410 Tcf,
more than the sum of the Barnett and Haynesville Shale. Another
promising shale play, the Utica Shale, is under exploration. It spans
bigger area than that of the Marcellus and may hold huge amount of shale

To sum up, the shale
gas is promising and the technology is sound, even though some issues
are unsolved. It may be the energy savior in the future. It is too early
to say no to it.


7.8 磅



Savitha Haneef's picture

I agree with your comment. It is too early to say no to shale gas. There are safety issues associated with shale gas exploration but by using advanced technologies and effective legislation  the risk can be managed to an extent. By horizontal drilling, the need for more wells in a single field is reduced. Lesser wells means lesser impacts to the environment, noise and water use.

Fluid handling techniques need to be improved to make drilling and stimulation work less impactful to the environment and also prevent any accidental leakage to nearby land and water sources 



An overview of modern shale gas development in the united states ;J.Daniel Arthur,Bruce Langhus, David Alleman

Savitha Haneef

MSC Safety & Reliability Engineering

Sineenat Kruennumjai's picture

Topic 50: Shale Gas Harmful or not, Economical or not
 Economical or not
Nowadays, hydraulic fracturing is used to produce shale gas. This technology, especially when it is combined with horizontal drilling, can significantly increase in the yield of shale gas production. If only the economic issue was consider, hydraulic fracturing will be seen as the valuable technique in order to increase the energy supply.

 Gas Harmful or not
 Yet, if the safety and hazardous issues were considered, this technique will be seen as very dangerous method. This is because its processes have lots of environmental effects. Earthquake for example, the injecting of high fluid pressure and the fracture of rock might cause a small earthquake. Moreover, the fluid use in this process consists of lots of toxic chemical compounds, and they can pollute ground or surface water. More than that, well’s casing might fail and then fluids will escape into rock, this situation can create the contamination of underground water.

 Should this be banned?
In my opinions, I think it should not be banded. This is because the methods for dealing with its hazardous effects are feasibility. Before implementation, all of the side effects of this process have to be investigated, mad confirmed of safety, in order to make sure that every working step will be done carefully.    

 Post by
Sineenat Kruennumjai
ID 51126536

amaka.ikeaka's picture

In the search for alternative sources of energy,
and rising global energy demand, extracting shale gas by hydraulic fracking is
becoming more popular, but a prevalent question is if the benefits outweighs
the risk? This process involves the injection of chemicals and “proppants” into
the rock formations in order to recover the gases trapped below the surface.
While this is an excellent source of energy, some argue that this technology
could contaminate groundwater sources and cause illness in local residents. Is
the safety of citizens regarded as less important than the society’s thirst for
energy? The following are the three main impacts of hydraulic fracking:

The use of
toxic chemicals as fracking fluid, which contaminates groundwater sources and
cause illness in local homeowners

infiltration of natural gas into water supplies, leading to flammable water and
documented cases of home explosions

The correlation
between hydraulic fracturing and seismic activity (earthquakes) in surrounding

Derek Porter.'s picture

Hi amaka.
I would like to touch upon the point you make about the environmental concerns of shale gas. With respect to the water supplies, there is such a large usage of shale gas in the USA although very little papers have been published suggesting the dangers. The public pressure groups regarding shale gas are calling for the ceasing of shale gas production. The solution should surely to get a government team to assess the dangers and simply produce an in depth scientific report. This would back up the claims. Yet I am asking the question why this hasn’t been done??
 I have found a paper (Ref 1) that states the results are incomplete and inconclusive. Furthermore the methane contamination (Ref 2) completed by a team of scientists also contains in the abstract that there was no changes in the levels of methane in active and dormant drilling areas.
In my opinion, the dangers due to contamination are minimal and should not be questioned until some published research is conducted.

Ref 2: Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing, Edited* by William H. Schlesinger, Cary Institute of Ecosystem Studies, Millbrook, NY, and approved April 14, 2011 (received for review January 13, 2011)

Kelvin Osaro's picture

Shale gas as an unconventional gas is considered safe when comparing to conventional gas and fossil fuels. This is due to lower level of carbon dioxide (CO2) and sulphur dioxide emission from the combustion of natural gas when compared to combustion by coal or fossil fuels [1]. However, there are some concerns over environmental impact with the production of shale gas. Firstly, the large amount of water required in hydraulic fracturing of unconventional gas production may affect availability of water for other use in a particular area and can affect aquatic habitats [1]. Secondly, hydraulic fracturing also creates a large amount of wastewater that may contain dissolved chemicals and other contaminants which require proper treatment before disposal or reuse elsewhere [2]. Thirdly, mishandling of water for fracturing may contain poisonous chemicals that may be released through spills, faulty wells construction, leaks or other exposure pathways thereby contaminating the surrounding areas [1, 2]. Fourthly, failure might occur from the well casing and hence allowing water to escape into shallow rock which can be problematic for drinking water supply [2]. Finally, it was observed that, wastewater injection into deep wells below the subsurface can cause earthquake that is largely felt and may cause damages [1]. From this environmental concerns, if proper safety measures are carried out to ensure this risk are mitigate as low as possible shale gas could be a major contributor to the projected future energy mix and may substitute not for coal as many originally hoped, but for renewable as well.  



 Extraction of shale gas can affect the environment.There are many harmful side effects of the extraction of shale gas. The chemicals and the waste used for the extraction will enter into the water body. The greenhouse gasses will be leaked during the extraction. These problems are to be solved. It is found that more amount of gas is leaked than recovered. And it says that the effect on global warming will be higher than expected. Fracturing is a process in which millions of litres of water is injected into the soil. In order to facilitate the fracking process 0.5% chemical is add to the water. This shows that thousands of litres of chemicals are injected into the soil. We are only able to recover 50-70% of this chemical mixed water. And the rest is left in earth which will contaminate the groundwater. These fracking can also lead to earthquakes. It is found that the average number of earthquakes occurring per year of magnitude of 3 has increased in United States. It is assumed that the fracking is the reason for the change.   

charlesggeorge's picture


I like to add furthermore with
your comments .On one of the reports released by the democrat Energy and
Commerce Committee in US that concerns about the hazardous chemicals released
by the hydraulic fracking companies which injected to the wells. In that report
they found out that some of the oil and gas service companies using more than
750 chemicals in the hydraulic fracturing process. Some of the chemicals like benzene,
methanol and lead are extremely toxic. While some chemicals like salt and
citric acid are harmless substances. These substances could be released soil
and may contaminate the drinking water.


in Oil and Gas Engg

AndrewRCarss's picture

Hi Charles,

I see you still have the same concerns over the production of shale since the last time we spoke :)

Whilst I do not share your concerns, and think the points you raise can be engineered out, I still do not think shale gas production should go ahead in the UK. This is because of the points I have already discussed with you on backtracking on low carbon energy policy. Why put all the effort into green energy production then start to produce energy using another finite resource?

The answer is of course simple...a quick fix for the flagging economy.

As the chancellor, Grorge Osbourne, has announced in his Autumn Statement just this week, the UK government is to introduce tax incentives to encourage UK companies to produce shale gas. George Osbourne has announced plans that the UK will be producing 26GW of power by 2030, using shale gas, and has plans to build 30 power stations to meet this target.

In announcing these tax incentives, the chancellor, almost in the same breath, is cutting tax incentives in solar energy..This I cannot understand

This plan will inject the much needed jobs and growth into the economy..perhaps for this the chancellor can be forgiven.

Andrew Carss - MSc Subsea Engineering (DL)

farman oladi's picture

Shale gas formation has been extensively investigated and used in the past few years, especially in US and recently in UK. Formation of gas in shale resources is within the organic rich rocks. Horizontal Hydraulic Fracturing by use of water, chemical and sand is a mean to unlock the hydrocarbons trapped in the shallow formations allowing natural gas to flow into the well. However some flow backs has been experienced in such procedures which are:·               Return of about 10 to 40% of the used fluid to the surface will cause potential chemical hazardous such as Carbon dioxide, hydrogen supplied, nitrogen and helium, brine and traces of mercury, arsenic and lead, which could be leaked in to the surface through this contaminated water.·               In some areas significant amount of water requirement will have aquatic affect on the environment and habitat due to water availability. ·             U.S. geological survey shows that Hydraulic Fracturing may cause earthquake, however they are too small to be of any concern.

The Flaw backs could be reduced through water treatment to remove TDS (Total dissolved solids), re-usage of untreated water.



Liu Yishan's picture

I saw some comments about the safety issues of shale gas production here. Some people thought that the exploitation of shale gas could be a threat to environment and it should be banned. Others believed that the shale gas could bring huge economic benefits to satisfy the demand of fuel in future, so it should be encouraged. I want to share some of my opinions about the exploitation of shale gas.
To begin with, I totally agree that the hydro-fracking is risky to the environment. The fracking, which is a technology to extract shale gas from underground, has amounts of controversial issues since it was widely used. As many people mentioned before, it could cause earthquakes and underwater pollution. This action may damage the health of people in fracking areas. The fracking has already been banned in some US states.
Although the fracking is dangerous, it does not mean we should not explore shale gas. The shale gas could reduce carbon footprint as it contains less carbon than other fossil fuel. For this reason, many governments encourage the exploitation of shale gas to achieve the target of reduction carbon emission. I think the best way to avoid the influence of fracking is to develop the technology until it is safety. The companies could use other methods to product shale gas, and the exploitation can go on after the development of fracking technology.


Kelvin Osaro's picture

The extraction of shale gas from deep underground shale rock formations through technological advancement in hydraulic fracturing and horizontal drilling has given rise to more profitable production of shale gas. This has also help to reduce the high cost of conventional gas. However, the economic benefits accrued from shale gas extraction depend on the regional proximity of shale gas deposits [2]. When a potential site is identified, site preparation, drilling and extraction of shale gas production begin with the need for employment opportunities, services and locally supplied activities. Hence, if shale gas is found in large commercial quantity, it helps to stimulate local business activities through infrastructural development in the installation of well production equipment and pipelines. In other words, with the production of shale gas from wells, royalties are paid to landowners and taxes paid to governments which thus stimulate the economy by providing additional resources for community services, such as education, healthcare and charities [1].

More importantly, one of the economic benefits of the Pennsylvania Marcellus shale gas was the value added to the economy from the gas industry which is estimated to be $3.88 billion in 2009. This contributed in creating 44,098 jobs and paying $389 million in state and local taxes in Pennsylvania economy in 2009 [2].

[2] Kinnaman T. C., 2011. The economic impact of shale gas extraction: A review of existing studies. Journal of Ecological Economics 70 (2011) 1243–1249.

t01sik12's picture

Shale gas is natural gas formed from being trapped within shale formations2. Shale gas is extracted from "unconventional" reservoirs, which are tight rock formations with low permeability. Shale gas can be harmful if not handled with care,this is because its processes have lots of environmental effects. Earthquake for example, the injecting of high fluid pressure and the fracture of rock might cause a small earthquake. Fluid use in this process consists of lots of toxic chemical compounds, which can pollute ground or surface water.

Beyond the risks posed by these underground drilling operations, other issues can arise at the surface:

• Employee injuries caused by blowout preventer malfunction, hose bursts, manual moving of fracturing fluid additives, fleet and transportation accidents to and from the job site, and environmental exposures (heat exhaustion, etc.)

• Public nuisance claims resulting from the damage to neighboring property caused by trucks

• Vehicle accidents caused by inexperienced drivers and rough terrain

Shale gas production has become more economically viable in recent years because of the advances in technology( horizontal drilling and hydraulic fracturing).

While horizontal wells typically cost up to three times as much as vertical wells, they can produce at up to five times the rate of verticals. Horizontal drilling requires fewer wells than is necessary when using vertical wells



2)   U.S. Energy Information Administration.

 Samuel Kanu

Elle Allswell David's picture

In the world the United States of America is a major producer of shale gas by Hydraulic fracturing. "The U.S. Energy Information Administration's Annual Energy Outlook 2013 Early Release projects U.S. natural gas production to increase from 23.0 trillion cubic feet in 2011 to 33.1 trillion cubic feet in 2040" ( Energy in Brief 2012 ).
There has not been any major accident recorded as a result of Shale gas fracking but there is the threat of the following:
1. Shortage of water, this is because production of shale gas requires large amount of water.
2. Threat of spills, leaks and faulty well construction. These risks are also inherent in the conventional method of Gas and oil productions which are properly taken care of as such proper care will be put in place.
3. Disposal of used water.
4. Threat of Earthquake as a result of reinjection of used water into deepwells.
The above mentioned Risks can be properly managed and as such reduced to As Low as Reasonably Practicable.
In 2012 records have shown that the U.S has achieved 70% of CO2 emissions reduction and that 95 % of the gases used domestically are produced within the country for which Shale gases production accounted for 40%.

CONCLUSION: Shale gas has not been found to be harmful but it is economical.


Tilak Suresh Kumar's picture

Adding to the above discussion, it seems that shale gas has significantly delivered high performance in reducing CO2 emmisions. Its has an insignificant issuse related to fracking but does other issues as discussed by Elle Allswell David in the post above.

Here you can see U.S. achieved approximately 70% of the CO2emissions reductions targeted under Kyoto (as compared to the 1998 EIA CO2forecast). That’s substantial progress. A major factor in CO2 emission reduction is shale gas, which, with the continued displacement/retirement of coal plants, has the potential to provide even more CO2 reduction benefits in the future. The benefits of the shale gas explosion include the newfound abundant supply which will provide more than enough natural gas to meet U.S domestic consumption needs and provide an expectation for relatively low natural gas prices in the future. However, the country’s increased reliance on natural gas (and displacement of some coal-fired generation) has already benefited the environment, and will continue to do so in the future.

Thus you see shale gas is a matured area which viable and an economically option also considering the environment and emissions.



Mehran Vakil's picture

Undoubtedly, exploiting any types of energy resources could be much beneficial. Specially the valuable ones like natural gas trapped in shale formation.
On one hand firms and homes require energy to meet their demands. Heating as well as electricity could be exemplified as social priority in order to utilizing energy. Thus, by selling or even exporting natural gas there could be acquired tremendous amount of money. It is also safe rather than conventional oil and gas, does not emitting over exceeded point of greenhouse gas, Kinnaman cited natural gas (shale gas) as a clean source of energy(Kinnaman, 2011).
On the other hand, taking into account of side expenses factors such as paying tax, having permission and license , providing fracing and extracting facilities and equipments, providing large amount of water, sand and chemicals as raw materials, recompensing due to destruction of environment, ecosystem etc, inform us about being offset of these expenditures and expenses. But actually, producing natural gas( shale gas) is much much economical owing to its precious characteristics(Kinnaman, 2011).

   KINNAMAN, T. C. 2011. Ecological Economics [Online]. Available: [Accessed 28/11 2012].

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