Environment

Throughout the world, coal seam gas is increasingly being used as an environmentally-friendly energy source as it is a cleaner-burning fuel than other fossil fuels.

When used for electricity generation, natural gas has approximately half the greenhouse gas intensity and only uses a minute fraction of the water that coal-fired electricity requires.

The exploration and production process is less invasive than conventional mining activity, in terms of the amount of land disturbance and transportation of the product to processing and distribution facilities.

In many cases, coal seam gas can be extracted without major disruption to surface activities. While Santos is conducting tests within coal deposits, the target is gas not coal. These seams are usually between 200 metres and 1000 metres below the surface.

Coal seam gas well site.

CSG production is non-invasive and a much lower intensity activity compared to coal mining. CSG is produced from boreholes which bring the gas to the surface where it is piped away, much like an irrigation network.

Gas is trapped within the coal by water, which needs to be drawn off before the gas can be extracted. As the amount of water in the seam decreases, the production of gas increases. A well is used to pump water out of the seam so that the gas can be extracted. The amount of water produced declines over time.

Water extracted from coal seams varies in quality and must be handled appropriately. The volume of water produced is variable: CSG fields in Queensland vary from no or minimal water production to over 1 megalitre per day. Water quality can range from drinkable to saline.

The method of using or treating water will vary depending on volumes produced, its quality and a number of local environmental factors. Careful consideration is given to water and aquifer management in the project planning stages of any coal seam gas extraction project.

View fact sheets about the GLNG project