What are we doing anyway?
The best place to start is with the gas that we are trying to extract. Whether it is the layers of shale (fossilised mud) in the US or coal (fossilised plant matter – peat, swamp plants) there are small pockets of methane gas distributed through the fossil bed.
The protein and other nitrogen based compounds in any ecosystem eventually break down into relatively simple forms like ammonia, urea or methane. Natural gas is methane and can be basically described as fossilised farts.
In a coal seam (or shale bed) there are microscopic layers of methane coating the individual coal particles. Some coal beds are gassier than others. The tragic Pike Hill coal mine in New Zealand was notoriously gassy. As the coal was mined it gave off lots of methane.
It is that methane that we are after.
Frack my coal seam
The process we are employing to extract the methane from these underground coal seams is to drill a well into the coal seam, fracture the coal seam to expose the gas, and extract the gas by using water to wash the gas off the surface of the coal.
The term fracking is an abbreviation of fracturing. The process being used in most of the extraction being undertaken now is called hydraulic fracturing. In this process the gas company injects a mixture of high pressure water and sand into the coal seam, forcing the sand into minute cracks that appear under pressure so that the cracks will remain open as the high pressure water rushes out.
After the initial well is dug, the gas capturing equipment is installed at the top of the well and then the well is fracked. The water that emerges is the process water or the production water, the gas is extracted and the water disposed of.
A well may be fracked many times in its life before the volume of methane being removed becomes too small to make it worthwhile.
So the simple picture is water and sand in, water and methane out.
The methane is then extracted from the water at the surface.
This sounds like quite a benign process but there are a number of additional extras that need to be considered.
Unpack that fracking fluid
As well as the methane, the coal is also coated with a range of other chemicals, including a high volume of salt.
Remembering that coal is a fossilised swamp and consists of all the carbon that was in the plants growing in the swamp, the stuff that is clinging to the coal is all the non carbonaceous material from the swamp. Most swamps are smelly, slimy places oozing with a rich mixture of living things. Oily slicks of aromatic hydrocarbons, like phenols are common place and sulphurous gases are not uncommon.
This cocktail of extras comes out with the methane in the water.
That water is also incredibly salty. It is significantly more salty than the saltiest inland bores and is a great potential danger to the inland water ways.
In addition to the “natural” compounds that are part of the coal seam, there are the fluids used to assist with the fracturing process. Even where pure water is being used to do the fracturing, there are lubricants, anticorrosion chemicals and emulsifiers just to get the process working properly.
In most cases, though, there is a cocktail of chemical extras involved.
If you are trying to wash the methane of the surface of the coal, why wouldn’t you add a little detergent or other surfactants to assist in the process, to dissolve some of the sticky hydrocarbons that are gumming up the coal seam, it might be useful to add some acids or alkalis to assist in the process.
The truth is that every coal seam is different, and there are a range of fracking fluids designed to maximise the methane production from each well. The fracking fluids may be selected or mixed on the spot based on the results being obtained in the field.
The other F word
We might be fracking the coal seam, but the real concern is what we are doing to the rest of the environment.
The damage to the landscape done by at least 22,000 wells in an arc from south west Queensland to the Capricorn Coast is one thing, the extraction of one hundred and fifty tonnes of salt a day is another#. The potential damage to the Great Artesian Basin is a third aspect that deserves special attention.
(# Coal Seam Gas Discussion Paper)
The Great Artesian Basin covers a huge part of Australia, larger than the area covered by the Murray Darling Basin. It is an enormous resource of fossilised water, on which a large amount of Australian agriculture depends for its existence. Without the Great Artesian Basin there would be no outback beef industry and many of the irrigation areas in Australia’s inland would not exist.
There are two primary threats to the Great Artesian Basin.
One is that we could use all the water up.
This water has been underground for hundreds of millions and it is inconceivable that we might consider it a renewable resource. We are mining that water, on which future generations depend to extract a non renewable energy source at very high cost*.
We are mining the water at incredible volumes. We are talking about tens to hundreds of gigalitres per year, that is hundreds of Megalitres per day over the lifetime of the project.
That is a vast amount of water. That is a similar quantity of water flowing down the Murray River in a good year. The natural discharge from the Great Artesian Basin, is estimated to be around 400Megalitres per day#, which is reasonable to assume is of a similar order of magnitude to the inflows. That means, that the Coal Seam Gas project could potentially use all the water that flows naturally from the Great Artesian Basin, meaning that any extractions by farmers, towns or industry anywhere else in the basin is depleting this ancient water supply.
So what we are doing is using a water supply that takes millions of years to create, that could supply us with water to grow food for centuries at current usage rates to satisfy twenty years demand for energy.
It is clearly insane.
# See Hydrogeological Framework Report on Great Artesian Basin – Qld Dept Natural Resources and Mines 2005
* See my article The Nett Energy Profit of Coal Seam Gas.
The other threat is that we could poison it
The interconnections between the various layers of groundwater and the coal seam are complex and varied. They differ widely from location to location.
The high profile problem that has been detected in this form of natural gas production is the mixing of methane with water that has led to the spectacular images of people setting fire to their tap water. Of more concern, however, is the appearance of carcinogenic hydrocarbons in people’s drinking water. Whether this is from substances washed off the coal during production, or from the fracking fluid itself is largely irrelevant, it is dangerous to allow these chemicals into drinking water.
It is these additional chemicals that have led to widespread illness in humans and stock across the US shale fields.
To poison the water coming to the surface during the mining operations is one thing, the greater danger is that this process is opening connections between the coal seam and the artesian water that have not previously existed. The problems that are emerging now may be the worst of the problems that this process will exist, or they may just be the beginning of much worse problems that will emerge in the future. We simply do not know.
Neither do we know what the long term result of injecting these chemicals into the coal seam will be. They might just sit there and remain a strange addition to the fossil record they might become a catalyst for a reaction we cannot predict. The truth is that we simply do not know.
Where the frack from here?
In an energy starved world, Australia has vast reserves of fossil and renewable energy resources. It is in our interests as a nation, and as individual members of this nation, to exploit those resources in a manner that allows us to build a robust vibrant future.
We simply need to make sure that we are not doing anything that could endanger this.
There is no urgency to get this energy out of the ground. The world’s demand for energy is not going to go away, the longer we wait, the higher the price of energy will be.
We simply need to proceed in an orderly fashion, well informed by the best science possible. If we rush we may make mistakes and these resources are too precious to destroy.
There is only one Great Artesian Basin, if we break it, the sound of “whoops” will resound so far into the future that our mistake will become part of the mythology of cultures we cannot even imagine yet.
Let’s no “go there”.