Are oil and gas operations harmful to human health?
Properly regulated oil and gas operations are safe and the Australian oil and gas industry has a strong compliance record. The people with the highest exposure to oil and gas are workers in the industry and an independent epidemiology program linked with Monash University clearly shows that petroleum industry employees have better health than the general Australian community and are less likely to die of the diseases commonly causing death – including cancer, heart and respiratory conditions. For more information, see this webpage.
Is hydraulic fracturing a new technology?
Hydraulic fracturing has been around for a long time, with the first use of hydraulic fracturing taking place in 1949. The process has been used safely in oil and gas for more than 65 years in more than 2 million wells around the world.
Does anyone understand hydraulic fracturing (fracking) or know what chemicals being are used?
All chemicals used in hydraulic fracturing are disclosed to the relevant regulator for assessment and approval for use. In several states, lists of these chemicals are published in their entirety so that anyone can view what is being used in an operation.
Water and sand comprise about 99% of the volume of fracking fluid. Companies must identify the chemicals being used in any fracking operation and detail any likely interactions with the water and rock formations in the area being fracced.
What chemicals are used in fracking and why are they necessary?
Fraccing fluid is generally 90% water, 9.5% sand and 0.5% chemical additives. Most of the chemicals used in fraccing are found in familiar household products and food additives. Commonly used substances include guar gum (a thickener found in food products), acetic acid (in vinegar), sodium chloride (salt), ethanol, sodium bicarbonate (baking soda) and sodium hypochlorite and hydrochloric acid (both used in swimming pools), cellulose (used to make paper), acetic acid (the active part of vinegar) and small amounts of disinfectants. These chemicals are all used in very low concentrations and in almost all cases they are biodegradable, meaning they break down.
Chemicals are used because the tiny cracks in the rock created by fracking will quickly close unless they are held open in some way. This is done by injecting a proppant made from sand into the cracks. But sand does not dissolve in water so a thickener (guar gum) is needed to carry the sand. Other chemicals help reduce friction, remove bacteria and prevent scale from building up in the well.
All chemical additives are assessed, fully disclosed and managed according to strict government regulations. In some states and in the Northern Territory, the full lists of chemicals are published on government websites.
Are cancer-causing chemicals such as BTEX used?
No. In Australia, BTEX (benzene, toluene, ethylbenzene and xylene) chemicals are not allowed to be used in fracking fluids. BTEX chemicals may occur in natural water sources, so in some instances trace levels of these chemicals may be detected following hydraulic fracturing. They can also be detected in industrial and irrigation waters that farmers and pastoralists use all the time.
How can we be sure fracking fluids won’t contaminate the environment?
Following the completion of a fracking stage, between 20% and 70% of fraccing fluid is recovered and stored in lined pits or in steel tanks so that it can be reused in another fraccing stage or in another well.
When no longer needed, the fluids and residue are placed in lined evaporation ponds. The bulk of the material is sand that returns from the bore plus the remaining fluid with the additives. Most of the additives will break down fairly quickly under light and the sand will settle out with the remaining small amount of salt. Once these have dried out, the remaining residue is taken away to a licensed facility for disposal.
Do drilling and fracking cause gas to migrate into waterbores and aquifers?
Natural gas wells are constructed to ensure gas cannot migrate to neighbouring bores and aquifers. It is not in the gas companies’ interests to allow leakage of gas into aquifers. Such leaks would make it difficult to extract the gas and would reduce the amount of gas available for sale.
The shale rocks being fractured are 2-5km underground, whereas the aquifers containing potable water used for drinking and by industry are generally within 300 metres of the surface. So more than 1.5km of barrier rock separates fracture zones from useable water aquifers.
The design of the well and the cementing and casing practices also protect the aquifers from water entering the bore hole or the gas and or oil from the hole entering the aquifer. The standards for oil and gas wells are far higher than those applying to water bores.
Wells have multiple layers of steel casing and specially engineered concrete. These separate the contents of the well from water aquifers. Each segment of steel casing is cemented in place then pressure tested and scanned to ensure there are no cracks or leaks before the next layer of casing is inserted and cemented in place. The standards applying to oil and gas wells drilled through water aquifers are very high and much higher than those applying to water bores.
The use of multiple layers of protection around wells to ensure no connectivity with water aquifers has been used in the production of conventional oil and gas for many decades. Instances of well failure are very rare.
Could the fractures extend vertically into drinking water aquifers?
No. Each fracture stage is individually engineered and controlled to limit fractures to the oil and gas bearing rocks. It is also physically impossible for fractures to extend more than 150 metres either side of a well (less vertically) because of the high pressures found in rocks at those depths. Extensive research on hundreds of wells in the US has conclusively demonstrated that the fractures induced by the process are confined to the rocks close to the target zone.
Is fracking more risky when combined with horizontal drilling?
No. The same technology, engineering and risk management processes are used to frack a vertical well as to frack a horizontal section of a well. In fact, horizontal wells into shale rocks are deeper than vertical wells into conventional oil and gas fields so there is even greater separation between fracture zones and drinking water aquifers.
How do companies ensure that evaporation ponds do not overflow into local water courses during or after heavy rain?
All by-products of drilling and hydraulic fracturing are disposed of in line with regulatory requirements and are managed with consideration for environment and weather conditions. For example, in areas that receive high rainfall, companies must show the relevant regulator that their storage facilities can accommodate additional water. In some cases, companies will plan activities for drier times of year.
Does fracking require a lot of water?
Fracking does require water but far less than industries such as agriculture or mining. Each hydraulic fracturing stage can use about 2.5 million litres of water – equivalent to the water in an Olympic size swimming pool. A well subjected to multiple fracking stages could require between 4- 22 ML of water. Where multiple fracks are done much of the water can be reused, which reduces the overall requirement for water. Once a well is fracked it does not need to be repeated each year so this is a one-off water requirement unlike mining and agriculture.
It is important to note that the gas industry can use salty water or non-potable water for fraccing. The industry aims to use water from aquifers deep below the surface that it can access when drilling, rather than tapping the freshwater aquifers used by people and agriculture.
How do operators ensure they are not depleting or contaminating ground water sources?
Companies use extensive monitoring to detect any possible changes in the environment as a result of operations. Before, during and after activities begin, monitoring is put in place to measure the potential impact on the environment. Before drilling a well, companies undertake extensive surveys to fully understand the environment. This includes baseline surveys of water levels and chemical analysis of water in local bore fields before, during and after drilling, fracking and production operations. Monitoring programs are closely regulated by the government.
All exploration and drilling activities are closely regulated by the government. Before obtaining approval to drill or frac, operators must develop environmental management plans that describe what the risks are and how they will be managed. Every step of the drilling and fraccing process must be reported to the regulator, which will closely monitored these operations.
Will sink holes be created as oil and gas is drained from below the ground?
No. This has not occurred with conventional oil and gas production and is even less likely to occur with production from shale rocks due to their greater depths and higher pressures. Oil and gas are drained from the tiny gaps between rock particles. The sandstone or shales remain in place so it is not possible for underground caverns to be created.
Will shale gas production require thousands of wells to be drilled closely together and restrict other land uses?
Due to their greater depth, shale wells are very expensive to drill so operators have a cost incentive to minimise the number of wells required. With horizontal drilling, multiple wells can be drilled from the same drilling pad, which minimises both costs and land disturbance. Once a field enters production, a well pad could be required every one to four kilometres. Each well pad would cover less than the size of a suburban house block. The location of wells and pipeline routes is agreed in consultation with landholders.
How can we be sure that wells will not deteriorate over time and cause environmental problems 50 or 100 years from now?
The risk of a well casing failure in Australia is low because the industry is committed to ensuring that wells are constructed and maintained to the highest standards using the latest available technology. Specially engineered steels and cement used in well casings are designed to withstand pressures far in excess of those found underground. In the absence of air and water, steel does not corrode and there well casings have been recovered after 40 years with very little deterioration. A 2011 study by the US Groundwater Protection Council showed that less than 0.1% wells drilled since the early 1980s had issues with well integrity (12 out of 34,000 wells in Ohio and 2 out of 187,000 wells in Texas). Most of these were drilled in the 1980s and 1990s before improved cement formulas and regulations were in place.