Environment

The hydrogeological summary of groundwater system (PDF) in the region, includes a review of data collected from the Camden Gas Project.

Produced water is natural groundwater that is removed from the coal seams (which are approximately 700 metres below the ground) in order to allow the natural gas to flow. AGL analyses produced water quality from a selection of operating gas wells each quarter, as described in the Groundwater Management Plan. The monitoring results are available in the document library and on Monitoring Data.

In 2011 and 2012, AGL’s water quality monitoring program found the produced water from some gas wells had significantly lower levels of salt than expected (at a level similar to rainwater or river water) and also a different ratio of the type of salts than is typical for coal seam gas wells at the Camden Gas Project. AGL wanted to understand why.

After conducting internal investigations, AGL engaged Parsons Brinckerhoff to investigate the lower salinity of produced water coming from some gas wells and to provide reasons why this was happening. Following expert chemical and isotope analysis, Parsons Brinckerhoff found that the low salinity water does come from the coal seam but it has been physically and chemically changed due to changes in pressure and temperature. The results from this investigation are very important in continuing to build on our comprehensive understanding of groundwater, produced water and coal seam gas operations for the Camden Gas Project. Download the 2013 Parsons Brinckerhoff report (PDF) and summary (PDF).

As part of its coal seam gas exploration and production programs in NSW and QLD, AGL Upstream Gas commissioned a desktop study on the occurrence of naturally occurring hydrocarbons in groundwater from Permian coal measures and associated sedimentary rocks. The report, prepared by CSIRO, Earth Science and Resource Engineering - Petroleum and Geothermal Research Portfolio Group, concluded that most of the detected total petroleum hydrocarbons, PAH (polycyclic aromatic hydrocarbons) and BTEX (benzene, toluene, ethyl benzene and xylenes) compounds appear to be naturally occurring.