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LPG is Not Coal Seam Gas

There is some confusion over what Coal Seam Gas (CSG) is and what it is not.
While CSG may contain a number of gases, it is characteristically 95% to 97% pure Methane. 
LPG is not Methane. 

LPG is Propane.

Coal Seam Gas Explained

CSG in summary…

  • Coal seam gas, also commonly referred to as CSG, is natural gas.  

  • It is the same natural gas (Methane) that is piped through the gas mains that go to many Australian homes and businesses.

  • In fact, coal seam gas is also known as coal bed Methane, as it is extracted from coal seams that are typically 300 to 1000 metres below the surface. 

  • Drilling for CSG may involve the controversial practice of "Fracking" - a common term for hydraulic fracturing.

  • LPG is propane whilst CSG is methane.  Two distinctly different gases.  LPG is not CSG.

What is Coal Seam Gas?

The difference between conventional natural gas and CSG is the geology of the natural underground reservoirs from which they are produced and the methods of withdrawal.  
Conventional natural gas is sourced from reservoirs that largely consist of porous sandstone formations capped by impermeable rock.  
The gas can move to the surface through the gas wells without the need to pump.
CSG is natural gas that is trapped within an underground coal seam. 
It is held there by the pressure of naturally present water in the coal cleats and fractures, that are within the coal deposit.
CSG is brought to the surface through drilling of gas wells.  
To facilitate this, the water is extracted from the coal cleats and fractures.  
This reduces the water pressure, allowing the Methane to be released from the coal seam.  
As the well progresses over time, the amount of water removed decreases and gas production increases.
As it exits the well, the water in the gas is separated. 
Depending on its intended use and quality, produced water can be used directly, treated and then used, or directly reinjected.  
It typically contains salt and other impurities and it is generally not fit for human consumption in its natural state.
Australia has relatively large supplies of CSG, especially in Queensland and New South Wales.  
CSG has been produced in Queensland’s Bowen Basin since 1997 and in the Surat Basin since 2005.  
Exploration is also occurring in other Queensland basins, northern NSW, and other parts of Australia where there are known coal deposits.

Coal Seam Gas Well

Coal Seam Gas (CSG) Well
Source: CSIRO

What is Fracking?

Fracking is a common term for hydraulic fracturing.
It is a technique used to increase the flow of oil or natural gas from a well.
The process involves the high pressured injection of fluid into the well.
The pressure achieved causes tiny cracks in the underground layer being targeted, allowing the oil or gas to flow more freely out of the well.
The fluid used in this process contains a small amount of chemicals, but is 99% water and sand or a ceramic substitute.
The sand particles are used to hold open the tiny pathways that are created.
Fracking is not required or employed on all wells.
In fact, coal seam gas and fracking are not synonymous.
Less than 10% of coal seam gas wells in Australia are fracked.
Fracking is the practice that causes the greatest level of concern within the community.  
It consumes a great deal of water and has the potential to contaminate other water sources, although steps are taken to prevent this.  
There are also claims that it may cause seismic activity.
However, contrary to popular belief, fracking is not new. 
It has been used in Australia for nearly 50 years.
It has a good safety record and there has never been a proven case of aquifer contamination as a result of fracking. 
This is an impressive record, given that over two and a half million wells have been hydraulically fractured worldwide since 1949.

How is CSG Used?

There are two basic distribution channels for coal seam gas.  
CSG can be piped to processing facilities where it is dried, compressed and fed into commercial pipelines.  
It is used just like any other natural gas supply.
CSG can also be processed into Liquefied Natural Gas (LNG).  
The Methane is cooled to -161°C, at which point it becomes a liquid.  
When it becomes a liquid it is greatly reduced in volume and much easier to transport.  
Using both conventional natural gas and CSG, LNG is an enormous growth industry, providing increased jobs and economic growth for the country.  
In fact, Australia is forecast to become the world’s largest exporter of LNG within the next ten years.
 
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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.