CO2CRC Otway Project

Frequently asked questions about the Otway Project Stage 1

What is climate change?
What is CCS?
What are the benefits of CCS?
What happens during the research project?
Is the gas (CO2) local?
How much CO2 will be stored underground?
What are the current levels of CO2 in the soils, air, etc?
What happens if it (the CO2) does leak?
Will the CO2 work its way out in 50 years?
Is it vaporising down there?
How do you know the gas isn't going to come up the side of the well?
If what you're doing here is successful, will you do something at Gippsland?
Can you do this (geosequester CO2) where power stations are situated?
Can't other uses be found for CO2 — they' ve been taking gas out of the Boggy Creek well for years? Why not invent something that can extract the CO2 that is currently out and about?
How are people going to extract the CO2 out of the atmosphere to store it underground?
How can large amounts of CO2 be used positively to return the levels to normal?
The CO2 being extracted is currently stored safe, for free and without monitoring and currently doesn't leak — why take it out?
Can the injection and storage of CO2 cause cracks in the rocks?
How will you protect cattle and property such as fences and gates?
Will the environment be affected by the project?
What will the affect on groundwater be?
Will there be any odours associated with the project?
What will people see from the roadside?
This used to be a volcanic area. Is the geology stable enough for this type of project?
Is there a possibility of the injected CO2 entering artesian water or a higher water table. And, if so, what is likely to happen to that water?

Q. What is climate change?

A. Greenhouse gases contribute to global warming and potential climate change. Carbon dioxide (CO2), the most common greenhouse gas, enters the atmosphere during the burning of fossil fuels, such as natural gas, oil and coal. Scientists and government believe the causes of climate change need to be
addressed as soon as possible.

Carbon capture and storage, along with energy efficiency, renewable energy and using less carbon-intensive fuels, will help decrease greenhouse gas emission overall address climate change.

>> More information

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Q. What is CCS?

A. CCS stands for carbon (dioxide) capture and (geological) storage , also known as geosequestration. CCS is the capture of CO2 from major emission sources such as power stations and industrial facilities; and the transport; the injection; and the long-term storage of CO2 into deep, underground reservoirs, such as depleted oil and gas fields or saline aquifers that contain unusable, salty water.

CO2CRC is investigating the technologies associated with this method of greenhouse gas reduction by developing more efficient means to carry out the capture, transport, injection and storage of CO2.

>> More information

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Q. What are the benefits of CCS?

A. The great benefit of CCS is that large quantities of CO2 that would otherwise enter into the atmosphere following the burning of fossil fuels can be safely stored in the deep subsurface. A number of commercial projects are already underway in Algeria, off the Norwegian coast under the seabed of the North Sea; and in Canada.

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Q. What happens during the research project?

A. During the project, researchers extract naturally occurring CO2 and methane from a gas well (Buttress) in Nirranda South. The gases are compressed and piped to a depleted natural-gas field. Here, the CO2 and a small amount of methane will be safely injected and stored at least two kilometres below the Earth's surface.

CO2CRC drilled a new well at CRC-1 also in Nirranda South for the injection of CO2 while an existing well is used as part of a world-leading monitoring program.

>> More information

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Q. Is the gas (CO2) local?

A. Yes. The CO2 is coming from a natural gas well in Nirranda.

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Q. How much CO2 will be stored underground?

A. Currently, we have injected over 65,000 tonnes of CO2 rich gas into the geological storage site at CRC-1, which is a depleted natural gas field.

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Q. What are the current levels of CO2 in the soils, air, etc?

A. We took regular samples of the air, soil and groundwater to measure the existing CO2 levels in the local environment. We compare these levels to those taken while the project is underway to monitor any changes in the measurements. We will investigate the causes of any changes to the levels of CO2 in the Nirranda South environment during and after the project. In the unlikely event a leak has occurred from the project site, we will immediately become aware of it through our monitoring program and take the necessary action. It is important to note that CO2 is a naturally occurring gas. We exhale it during respiration; plants use it as part of photosynthesis; and it is non-flammable.

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Q. What happens if it (the CO2) does leak?

A. Following the detailed studies our scientists have undertaken; CO2CRC is confident that the CO2 will not leak. The Intergovernmental Panel on Climate Change considers that at a carefully chosen site less than 1 per cent of the stored CO2 will leak into the next rock strata only, not the atmosphere, over 1000 years.

CO2CRC is aiming at the same level of certainty for the CCS research project. Several layers of rocks and saline aquifers separate the CO2 injection zone from groundwater and the atmosphere, which is another reason why CO2CRC chose this site for our research project. The geology is very suitable for storage of CO2 making the chance of risk of leakage to groundwater and the atmosphere minimal.

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Q. Will the CO2 work its way out in 50 years?

A. This is unlikely given the explanation provided in the answer above.

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Q. Is it vaporising down there?

A. No. The CO2 is injected two kilometres into the subsurface as supercritical fluid. The pressure exerted in the Earth's crust at 800m and deeper keeps the CO2 in a liquid-like form. The liquid CO2 is then trapped in the rocks in a number of ways:

  1. In geological reservoirs, such as the Naylor field, which is a depleted natural gas field or reservoir, the CO2 is geologically trapped to ensure that it does not reach the surface. This trap or seal is made up of a particular type of fine-grained rock known as a mudstone or shale and in Nirranda this is the Belfast mudstone which is several hundred metres thick.
  2. Solubility and mineral trapping are two other very important mechanisms. Solubility trapping involves the dissolution of CO2 into the saline water in the reservoir. In mineral trapping the CO2 combines with minerals in the rocks to form stable carbonate minerals.

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Q. How do you know the gas isn't going to come up the side of the well?

A. The well-casing is cemented in place, with the space between the casing and the ground filled with a special oilwell cement. This protects the casing and prevents any fluids from moving behind the well. The integrity (condition) of the well has been checked recently and found to be safe.

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Q. If what you're doing here is successful, will you do something at Gippsland?

A. We have carried out a major study of the Gippsland Basin, which is offshore of the Latrobe Valley and found that its potential for the long-term storage of large volumes of CO2 is excellent. We expect to undertake further studies of the Gippsland Basin for the Victorian government.

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Q. Can you do this (CCS) where power stations are situated?

A. This would be an ideal solution. The storage sites for CO2 require a specific geology: sandstone, which is porous and permeable to allow the CO2 into the pores of the rocks where it will be stored and an overlying, fine-grained rock, such as a mudstone or claystone that will trap the CO2 in the sandstone layer. An ideal scenario would have this type of geology close to a power station, but it would be more likely that the CO2 will be transported by pipeline to a geological storage site.

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Q. Can't other uses be found for CO2 — they've been taking gas out of the Boggy Creek well for years? Why not invent something that can extract the CO2 that is currently out and about?

A. Some alternative uses for CO2 do exist, and the CO2CRC has been looking into this, but these uses are unlikely to re-use enough CO2 to make a significant reduction to the large quantities of the gas that is being emitted into the atmosphere and potentially leading to global warming. We need to remove CO2 in the order of megatonnes - millions of tonnes a year to make deep cuts in greenhouse gas emissions, so a portfolio of solutions are needed, from biological sequestration and renewable energy to CCS, in order to effectively reduce CO2 emissions.

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Q. How are people going to extract the CO2 out of the atmosphere to store it underground?

A. In CCS, the CO2 will be captured from industrial sources before it is released into the atmosphere. At present, the only effective method of extracting CO2 from the atmosphere is through biological sequestration, which is the uptake of the gas by plants.

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Q. How can large amounts of CO2 be used positively to return the levels to normal?

A. CO2CRC and other organisations are researching alternative uses for CO2. But the industrial sources of CO2 are so large that a portfolio of solutions is needed to achieve deep cuts into greenhouse gas emissions. Australia alone emits 560 megatonnes of CO2 each year, half of which is emitted from power stations. Reducing greenhouse gases requires a portfolio of responses including increasing energy efficiency; switching to less carbon-intensive fuels; biological sequestration; and harnessing renewable energy from the wind, sun and tides as well as CCS.

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Q. The CO2 being extracted is currently stored safe, for free and without monitoring and currently doesn't leak why take it out?

A. CO2CRC is conducting a research program into the geological storage of CO2. The aim of the project is to show that CO2 capture and storage is a viable, safe, secure option for greenhouse gas reduction in Australia.

The lessons learned from monitoring and other activities in this research project will open the way for the technology to be applied to large scale emissions. Our monitoring and verification program is in many ways the most important part of the project as it will demonstrate to the community, governments at all levels and industry that CO2 can be safely transported, injected and stored in the deep subsurface.

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Q. Can the injection and storage of CO2 cause cracks in the rocks?

A. CO2CRC geologists have studied the geology in the Otway Basin and particularly at Nirranda South for a number of years. The Nirranda South site was chosen for its geology, which is ideal for testing the geological storage of CO2. During the project, CO2CRC will inject CO2 into a depleted natural gas reservoir. Between 55 000 and 100 000 tonnes of CO2 will be injected into the reservoir, which is significantly less than the amount of natural gas that was extracted. This means that it is highly unlikely that the reservoir would be overpressurised, or that fractures would be formed that could allow the leakage of CO2.

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Q. How will you protect cattle and property such as fences and gates?

A. CO2CRC scientists and our project contractor will follow strict guidelines developed in association with landowners in regard to taking the proper care of cattle and property.

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Q. Will the environment be affected by the project?

A. Again our risk assessment shows that negative effects on the environment will be highly unlikely. Of course, some land will be disturbed with the laying of pipelines and the drilling of new wells, but this will be rehabilitated as required to meet in legal contracts we have with the landowners on whose properties we are carrying out the project.

We are also bound by the Victorian Environment Protection and Petroleum Acts as well as conforming to local government regulations to ensure that properties and the environment are well protected.

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Q. What will the affect on groundwater be?

A. The chances of CO2 entering groundwater that is used in the area are very small and even then the consequences are going to be minimal as the volumes of the gas would be very low. This is because the cap rock immediately above where we plan to inject the CO2 is very fine-grained (impermeable) and would not allow the gas to pass through it. This is what we refer to as mudstone or shale. If by some means the CO2 did pass through it, overlying the impermeable cap rock is another sequence of rocks and saline aquifers. Our computer modelling shows that the CO2 would dissolve in this water. This sequence of impermeable rocks occurs several times in the area into which we plan to inject CO2 and thus protects the groundwater effectively.

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Q. Will there be any odours associated with the project?

A. CO2 has no odour and there are no plans to add an odour at this stage. No odours from the well sites or compressor are anticipated.

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Q. What will people see from the roadside?

A. People will see little more than they see at present. Nothing will be visible from the Great Ocean Road. From Callaghans Rd, the Buttress well-head is currently visible. It is situated within a fenced-off area or enclosure (36m wide and 54m long) about 400m from the road. In addition to the well-head, the enclosure will also contain a compressor. The compressor will be in an EPA-approved noise-reduction. This means that at 20m distance from the enclosures the noise level will be equivalent to that of a normal conversation. The noise-reduction enclosure will be the size of a small shipping container but slightly wider (about 2m high and 3.5m wide and 6m long). The compressor inside this enclosure will be approximately 1.5m high and 2m wide.

All the equipment at the Buttress is 800m from the nearest house. The injection well and monitoring well will be visible from both Sodas and Brumbys Rd, but mainly from Brumbys Rd. This road is usually accessed only by the landowner on whose land (which CO2CRC has leased) the wells will be situated.

None of these buildings are larger than a double car garage.

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Q. This used to be a volcanic area. Is the geology stable enough for this type of project?

A. One of the main reasons the area was selected for the CCS research project is that senior CO2CRC scientists have researched the areas and found it to be geologically stable. Additionally, the CO2 will be stored into a reservoir, or field, two kilometres underground that had previously stored natural gas for many thousands of years. Many of these accumulations or deposits of natural gas predate the volcanic activity and appear to have been unaffected by it.

And for the technically minded:

  • Volcanic activity, known as the Newer Volcanics occurred in south-eastern Australia between roughly 3 million and 5 thousand years ago and is now extinct. Tower Hill, the most recent volcanic eruptive centre near the geosequestration research project, has been extinct volcano for 30,000 years. The nearest volcanic centre to the project is approximately 25km to the north. Geophysical examination shows no occurrence of volcanic intrusions in the project region.
  • Intrusive volcanic rock occurring in a storage site would occur as horizontal intrusions, known as sills, orvertical intrusions, known as dykes. These volcanic rocks are very impermeable making it very difficult for CO2 to migrate through. Sills will act as vertical-flow barriers and in many cases will aid in the containment of the CO2. Dykes however, will act as horizontal flow barriers and can reduce the capacity of a storage system. Dykes can sometimes fracture the rock it intrudes and this effect must be considered if the intrusion occurs through a seal rock. Both volcanic intrusion types will also be reactive to CO2, releasing cations into the system that then mix with the CO2 to form carbonate minerals, locking the CO2 into the rock.
  • The subsurface geology of the geosequestration research project has been very carefully studied and there is no evidence whatsoever of sills or dykes. It is also important to remember that that there are many accumulations of hydrocarbons, such as natural gas, in the area which predate the volcanic activity and which appear to be unaffected by volcanic activity. Past volcanic activity, yet to be scientifically determined as extinct in present day, will not create unstable geology for geosequestration. The occurrence of intrusive volcanic rock in a geosequestration site must be considered. However, in the case of the geosequestration research project, volcanic intrusions are not observed.

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Q. Is there a possibility of the injected CO2 entering artesian water or a higher water table. And, if so, what is likely to happen to that water?

A. The chances of CO2 entering water close to the surface are extremely small and even then the consequences would be minimal as the volumes of CO2 would be very small. This is because the rock immediately above where we plan to inject the CO2 is impermeable and would not allow the gas to pass through it. This is what we refer to as cap rock or a seal. Despite this, if by some means the CO2 did pass through the cap rock, there is another layer of rocks containing saline water in which CO2 would dissolve, and this is overlain by another seal. This sequence of impermeable rocks and porous rocks repeats itself several times in the area into which we plan to inject CO2 and will fully protect the shallow aquifers that are used by farmers.

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