The deeper worries about coal seam gas

Parliament house flag post

The deeper worries about coal seam gas

Posted 15/06/2012 by Simeon Hui

One-third of Eastern Australia cooks its breakfast, warms its homes, and generates its power from natural gas, the main component of which is methane, supplied by coal seam gas (CSG) operations. Our need for natural gas has allowed CSG operations to grow, but critics contend that this has not always been accompanied by sufficient understanding of the social and environmental implications. Ground and surface water contamination, water consumption, and waste disposal are but a few issues fuelling the ongoing debate. However, reports of deeper risks are now surfacing.

The United States Geological Survey (USGS) recently indicated that CSG activities in the US appear to have contributed to an increase in the number of earth tremors. Back in 1970, the US midcontinent experienced about 21 events a year, but this has abruptly increased to 31 events a year around 2000 and 151 events around 2008. Before we conjure up images of toppling cities, note that a geologist defines an earthquake as any detectable rumbling in the ground, including those only recorded by sensitive instruments locked away in basements. The important point is that the USGS research showed that earth movements that are detectable by people (not just instruments) have increased along with CSG activities, and this highlights the extent of underground environmental disturbance that CSG activities can potentially cause.

Australia is well aware of concerns around CSG. On 22 March 2012, the government introduced legislation to Parliament to establish an Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development. (By this time, an interim committee was already in place, having been established by Environment and Water Minister Tony Burke on 27 January 2012.) During the debate, the Australian Greens and Bob Katter, MP both proposed moratoria on new CSG proposals (of five and one year respectively) but these amendments were not passed. At the time of writing, the legislation has passed the House and is continuing its passage through the Senate. The purpose of the committee proposed in the legislation is to provide government with robust independent scientific advice regarding CSG activities. One issue that has been flagged as important are earthquakes: could CSG mining activities trigger them? And, if so, what does this mean for Australia?

The CSG industry profits from the extraction of methane trapped in pockets and fractures inside coal beds hundreds of metres underground. The methane is purified and marketed as natural gas (for more information see this Parliamentary Library Background Note). Often, a process known as fracking will be used to help release the methane by fracturing the coal beds allowing the gas to escape. The fracking processes involves pumping a pressurised mixture of sand, water and chemicals into bores that have been drilled into coal beds. The pressurised mixture builds up stresses in the earth until the rock suddenly breaks, like bending a wooden ruler slowly till it snaps. Upon failure, the energy stored in the rock is converted to sound, heat and vibrations that fracture the coal beds and may be felt on the surface as an earthquake. Earthquakes occur naturally from the release of stresses that have been built up in the earth from natural processes. From January to June 2012, a total of 228 earthquakes were recorded in Australia (about 1.5 a day). However, there is now uncertainty over whether CSG operations may increase that daily average.

Wastewater reinjection
According to the USGS, the fracking process generates earthquakes small enough that only the attentive will feel them. However, more serious earthquakes may be triggered not by the fracking itself, but by disposal of wastewater used to fuel the fracking process. The wastewater that is recovered from fracking operations is dirty, saline, and not fit for consumption by humans or livestock. While the wastewater can be treated, this is an expensive operation and it is often more economical to dispose of the wastewater by reinjecting it back into the earth. These reinjection points are known as disposal wells. Injection of wastewater down disposal wells widens pre-existing cracks deep in the earth. However, the danger is that this wastewater can lubricate these pre-existing cracks. This allows rocks to relieve stress by shifting their position, and an earthquake may result. A good analogy for why this happens is the act of trying to remove a stubborn lid from a jar. From the strain against friction between the lid and jar, stresses build up proportional to how much effort is put in. It is possible to strain unsuccessfully to open a lid, but if the same amount of effort is put into a lubricated lid, the jar suddenly and unexpectedly opens.

Studies in the US have suggested that localised earthquakes, in some cases up to magnitude 5.2 on the Richter scale (a measure of the energy an earthquake releases), can be induced by injection of wastewater. Magnitudes around 5 will be felt by everyone, china may break and doors may swing. Magnitudes of less than three are unnoticed or discounted as a passing truck. Note this does not translate directly to ‘damage’, because that is determined by a combination of the earthquake characteristics (energy, depth of origin, geology, shaking time, and distance from civilisation), and the nature of affected buildings (e.g. wooden structures survive better than brick and mortar).

How many earthquakes could CSG activities be responsible for? It’s hard to know exactly, but the USGS suggests that only about a dozen out of 40,000 disposal wells actually trigger significant events;  more research is investigating the how, why and what can we do (on the management side) to minimise the risk.

The results of the USGS study highlight the potential risks of several CSG developments in Australia. Geological details vary from place to place, and Australia is not the same as the US, but it could still be at risk. Until recently, the reinjection of wastewater was not seriously contemplated here, but this is beginning to change. Last month, CSG company Santos released a booklet describing its research into the injection of treated waters into aquifers and trialling wastewater injection into the deep earth. While there are some benefits to the reinjection of water, such as to offset the environmental impacts of a water-hungry industry, there are now obvious implications for water quality and human-induced seismicity. The CSIRO is also researching the possibility of injecting carbon dioxide (CO2) into the coal beds to enhance methane gas extraction and, at the same time, permanently store CO2. While these activities have the potential to generate earthquakes, differences in the geology, maturity of technology, methods, and management may lead to improved outcomes. Importantly, the experiences of the US have placed Australia in a better position to prevent or minimise potentially damaging effects of CSG activities while continuing to enjoy its benefits.

*Updated 20 June 2012

Thank you for your comment. If it does not require moderation, it will appear shortly.
Facebook LinkedIn Twitter Add | Email Print


Flagpost is a blog on current issues of interest to members of the Australian Parliament

Parliamentary Library Logo showing Information Analysis & Advice




refugees asylum immigration Australian foreign policy Parliament elections climate change social security women welfare reform taxation Indigenous Australians Australian Defence Force welfare policy school education higher education private health insurance health financing emissions trading Senate Australian Bureau of Statistics employment people trafficking Asia statistics Middle East illicit drugs gambling health reform federal election 2010 Australian Public Service income management Medicare disability Sport United Nations environment industrial relations constitution transport politics criminal law Afghanistan health forced labour food public service reform aged care aid Australian Sports Anti-Doping Agency World Anti-Doping Agency United States federal budget Carbon Pricing Mechanism dental health international relations governance regulation Fair Work Act voting law enforcement electoral reform OECD Australian Electoral Commission WADA child protection poker machines Australia in the Asian Century steroids National Disability Insurance Scheme detention 43rd Parliament slavery health system leadership domestic violence parliamentary procedure International Women's Day accountability defence capability multiculturalism ASADA Australian Federal Police labour force people smuggling debt New Zealand Australian Crime Commission pharmaceutical benefits scheme political parties coal seam gas Human rights crime China Census election results UK Parliament Papua New Guinea banking corruption pensions children's health Aviation federal election 2013 foreign debt gross debt net debt Senators and Members ALP Newstart Parenting Payment Youth Allowance sea farers United Kingdom energy food labelling Australian economy violence against women vocational education and training military history by-election High Court skilled migration mental health Federal Court terrorist groups science social media Higher Education Loan Program HECS federal state relations youth paid parental leave same sex relationships customs planning doping health risks Gonski Review of Funding for Schooling sex slavery Special Rapporteur Northern Territory Emergency Response social policy ANZUS Rural and regional trade unions Foreign affairs election timetable Indigenous royal commission Productivity firearms public policy Population ADRV terrorism transparency research and development welfare ASIO intelligence community Australian Security Intelligence Organisation carbon tax mining employer employee renewable energy regional unemployment fishing European Union family assistance United Nations Security Council forestry Drugs welfare systems Indonesia children Constitutional reform local government codes of conduct terrorist financing homelessness Parliamentary remuneration money laundering Trafficking in Persons Report social inclusion paternalism environmental law US presidential election nutrition ODA Defence sitting days electoral divisions Southeast Asia administrative law universities TAFE Ireland citizenship asylum seekers early childhood education Canada Financial sector national security fuel disability employment Tasmania integrity standards NATO Australian Secret Intelligence Service sexual abuse World Trade Organization Australia public health housing affordability bulk billing water health policy Governor-General US economy export liquefied natural gas foreign bribery question time speaker superannuation public housing expertise climate Intergovernmental Panel on Climate Change Department of Agriculture Fisheries and Forestry Pacific Islands reserved seats new psychoactive substances synthetic drugs UNODC carbon markets animal health middle class welfare constitutional recognition of local government referendum consumer laws PISA competition policy US politics language education baby bonus Leaders of the Opposition citizen engagement policymaking Australia Greens servitude Trafficking Protocol forced marriage alcohol entitlements ministries Hung Parliament social citizenship maritime Iran regional students school chaplains federal budget 2011-12 salary Medicare Locals primary care Building the Education Revolution marine pollution sustainability prisons police deaths in custody electoral margins electoral pendulum electoral redistribution redistribution NSW redistribution WA redistribution ACT electoral boundaries ASEAN Sustainable Development Goals Double dissolution Senators safety vehicles MYEFO Pathology tertiary education Taiwan Xi Ma meeting family violence government financial advisers financial planners Financial System Inquiry Murray Inquiry China; Economic policy; Southeast Asia; Africa housing Speaker; House of Representatives; Parliament High Court; Indigenous; Indigenous Australians; Native Title ACT Indigenous education Norfolk Island External Territories emissions reduction fund; climate change child care funding refugees immigration asylum procurement Indigenous health e-voting internet voting nsw state elections 44th Parliament 2015 ABS Age Pension Death penalty capital punishment execution Bali nine Bali bombings Trade EU China soft power education Fiji India Disability Support Pension Antarctica Diplomacy by-elections state and territories Bills anti-corruption fraud bribery corporate ownership whistleblower G20 economic reform innovation Members of Parliament Scottish referendum Middle East; national security; terrorism social services Criminal Code Amendment (Misrepresentation of Age to a Minor) Bill 2013 online grooming sexual assault of minors ACT Assembly smoking plain packaging tobacco cigarettes Asia; Japan; international relations Work Health and Safety Migration; asylum seekers; regional processing China; United States; international relations fiscal policy Racial Discrimination Act; social policy; human rights; indigenous Australians Foreign policy Israel Palestine asylum refugees immigration political finance donations foreign aid Economics efficiency human rights; Racial Discrimination Act employment law bullying Animal law; food copyright Australian Law Reform Commission industry peace keeping contracts workplace policies same-sex marriage disorderly conduct retirement Parliament House standing orders prime ministers First speech defence budget submarines workers Somalia GDP world heritage political engagement leave loading Trade; tariffs; safeguards; Anti-dumping public interest disclosure whistleblowing Productivity Commission limitation period cancer gene patents genetic testing suspension of standing and sessional orders live exports infant mortality honorary citizen railways disciplinary tribunals standard of proof World Health Organisation arts international students skilled graduate visas temporary employment visas apologies roads Italy national heritage NHMRC anti-dumping Rent Assistance obesity evidence law sacrament of confession international days DFAT UN General Assembly deregulation Regulation Impact Statements small business Breaker Morant regional engagement social determinants of health abortion Members suspension workplace health and safety marine reserves hearing Victoria astronomy resources sector YMCA youth parliament Korea rebate Australian Greens presidential nomination Racial Discrimination Act political parties preselection solar hot water Financial Action Taskforce Horn of Africa peacekeeping piracy Great Barrier Reef Stronger futures political financing political education Social Inclusion Board early childhood National Quality Framework for Early Childhood Education and Care Murray-Darling Basin sanctions Norway hospitals republic President Barack Obama Presidential visits qantas counselling Korean peninsula Work Choices biosecurity hendra federalism federation preselection therapeutic goods Therapeutic Goods Administration plebiscites computer games pests suicide nuclear COAG Ministerial Councils floods ADHD stimulant medication advertising electricity extradition conscience votes poverty preventative health rural health coastal erosion Parliamentary Budget Office work-life balance

Show all
Show less
Back to top