Ground movement environmental risk scoping & management

January 2017March 2020
This project is a preliminary assessment of the relative extent of the various contributors to the net movement of the ground surface

Ground movement environmental risk scoping & management

Movements of the ground’s surface over time (up and/or down) might be caused by natural tectonic forces as the continent moves and local accommodations occur, by the swelling of soils and clays as they are inundated, by differences in vertical loading (e.g. water levels) over time, by agricultural activities whether livestock or cropping and by the abstraction of water and/or gas.

This project is a preliminary assessment of the relative extent of the various contributors to the net movement of the ground surface. The research is specifically focussed on results for the Surat Cumulative Management Area.

This research is working on:

  1. Creating a baseline that demonstrates the scale of net surface movement in non-CSG development areas.
  2. Developing an integrated, evidence-based workflow to quantify the magnitude of various processes to the net surface movement in these areas.

Improving the ability to understand surface movement will ultimately inform the development of best management practice strategies for strong environmental performance. There may also be opportunity to learn from surface movement observations in non-CSG areas.

Production of gas is one potential cause of measurable movement of the ground surface. It may be possible to be able to distinguish surface movement related to CSG from that influenced by other factors. This includes, but is not limited to, tectonics, changes in soil moisture (including rainfall) and associated shrinkage and swelling, the effects of groundwater abstraction and recharge , and land use change, each of which can contribute a component to net surface movement. Ground movement in the order of millimetres can be detected by a technique known as Interferometric Synthetic Aperture Radar (InSAR).

Separating and quantifying the different components of net surface movement ensures that:

  1. The distribution and significance of CSG-related surface movement is understood within the context of key geomechanical characteristics and processes of the shallow geological framework.
  2. Future surface movement associated with CSG development, as a proportion of net surface movement, can be forecasted more accurately.

Research to support these aims includes:

  1. Reviewing all processes (e.g. active tectonics, aquifer depressurisation and recharge, changes in soil moisture, geomorphology) which have the potential to contribute to net surface movement in the regions of interest.
  2. Interpreting and interrogating measurements of surface movement in non-CSG development areas to define spatially-dependent reference data for model validation.
  3. Developing models of net surface movement for the processes (e.g. shrinkage and swelling of soils, poroelasticity), which have been identified as the most significant in the regions of interest.
  4. Reviewing data to facilitate characterisation of the key processes, and identifying if there is sufficient data available, both in terms of soil composition and rock properties, to undertake the proposed modelling.
  5. Selecting a number of study locations from gas non-production areas, analysing them using the methodology developed in the project, and then using the predictions to validate and or history-match the modelling workflow.
  6. Determining any additional work which could potentially extend the developed workflow for application in gas development areas.

This project includes activities across a range of disciplines, including geology, hydrogeology, soil science, geomechanics, remote sensing, geostatistics, and geospatial data analysis. A multidisciplinary team comprised of researchers from within and outside UQ has been assembled to deliver this research. The project team will collaborate with other research providers and/or government organisation as needed.

PROJECT OUTPUTS

  • Research poster: UQ-CCSG Research Review (2018)
  • Project status: Underway
  • Project leader: Dr Christopher Leonardi
  • Research team: Associate Professor Phil Hayes, Professor Wendy Timms
  • Research group: The University of Queensland Centre for Coal Seam Gas & The University of Queensland School of Mechanical and Mining Engineering
  • Timeframe: January 2017 - March 2020
  • Project funders: APLNG, Arrow Energy, Shell, Santos, University of Queensland