Australia Pacific LNG Project

Groundwater monitoring of an LNG producing area in Queensland, Australia

Liquefied natural gas (LNG) is produced from large sedimentary basins of Queensland, Australia by depressurizing buried coal seams by pumping groundwater using gas production wells. For the past eight years, KCB has been commissioned by Origin Energy to supervise the installation of groundwater wells in Queensland’s Great Artesian Basin (GAB), undertake groundwater monitoring and to assess the impact of coal seam gas (CSG) production on surrounding groundwater receptors.

 

“Establishment of a groundwater monitoring network and the implementation of a groundwater monitoring program provides Origin Energy with critical information to support future studies relating to operational development, and allows the monitoring of potential groundwater impacts associated with gas production.”

-KCB Project Manager

Challenges

  • Understanding impact of coal seam gas (CSG) production on the GAB
  • Trial injection (recycling) of treated CSG process water back into the GAB
  • Measure ratio of treated CSG water to natural water over 16-year period in Precipice sandstone aquifer at Spring Gully

Solutions

  • Supervised installation and/or monitoring of over 450 groundwater wells across 200 privately-owned properties
  • Measured amount of free gas, water levels and pumping rates, and sampled water for analysis where possible
  • Modelled injection of treated CSG water over 60-day period under “best-estimate”, “maximum impact” and “minimum impact” scenarios
  • Conducted predictive modelling of injected treated CSG water using FEFLOW groundwater models

Successes

  • Developed baseline data for defining hydraulic properties and other aquifer characteristics
  • Assessed condition of privately-owned wells and groundwater quality across Surat Basin
  • Evaluated impact of treated CSG water on water pressure and quality in local aquifers in the GAB
  • Modelled particle tracking and head contour development in local aquifers in the GAB for 500-year period