Australia Pacific LNG undertook a series of aquifer injection trials targeting three different aquifers across four sites in the Surat Basin, Queensland. Following the trials, two operational schemes commenced operation in early 2015, with over 14GL injected to May 2017. Hydraulic and water quality responses observed during the short-term trials and through the long-term far-field pressure effects from operational injection have provided insight into how the scale of the imposed stress may lead to different hydrogeological interpretations. Examples will be presented of local versus regional hydraulic responses in the context of the system structural regime and how this has been used to advantage for injection scheme design, how hydraulic boundary behaviour may differ dependent on duration, water quality changes during long term pump tests, and intraformational heterogeneity and the associated hydraulic implications.