Sustainable disposal of salty water:
Santos had pioneered a sustainable solution to the need to dispose of salty water that accompanies the production of coal seam gas;
In an Australian first, Santos had successfully trialed the injection of produced water into fractured rocks more than a kilometre underground at its Fairview coal seam gas field in southern Queensland. In doing so, the company had adopted a strategy that, at current injection levels, will stop the equivalent of five tonnes of salt a day entering the Dawson River system;
A rise in the level of salinity in the formation water produced with the gas from the Fairview field required a new approach if Santos’ plans to significantly expand gas production were to be achieved.
Disposing into Dawson no longer an option: The previous disposal of less salty water into the Dawson River, without causing environmental harm, was no longer an option. The geological zone chosen as the destination for the injected water had no agricultural, economic or cultural value, and already contains water with a greater salinity than that being disposed of.
An economically beneficial green strategy: Constant injection of 9,000 barrels of formation water a day for 30 years equated to the safe disposal of more than 53,000 tonnes of salt where it will not affect the Dawson River system. And the environmentally sustainable strategy will unlock an additional 100 billion cubic feet of gas. The saline water injection strategy delivers simultaneous environmental and economic gains.