This scholarship is funded by an ARC Linkage Project to to support a full-time PhD student who is understanding research in the innovative use of geomechanical modelling to identify secure sites for carbon capture and storage.

Carbon capture and storage (CCS) is critical to proposed pathways to limit global warming to 1.5ºC, with an estimated total geological storage requirement of 190 Gt of CO2. However, existing CCS projects only capture and store around 40 Mt of CO2 each year, so considerable upscaling is required, including the characterization of many new storage reservoirs. Quantifying and managing the risks of fault reactivation is the leading obstacle to increasing the implementation of CCS, because CO2 injection into reservoirs results in increased pore fluid pressure, which can reduce the strength of rocks and faults, and induce brittle failure. This could result in induced seismicity, with hydraulic fracturing of sealing formations providing pathways for CO2 leakage. Sedimentary reservoirs that have undergone prior hydrocarbon production are thought to be the most favourable geological sites for CCS, since many have demonstrably contained large volumes of natural gases, including CO2, over Myr timescales. However, anthropogenic processes that involve the injection and extraction of fluids in subsurface reservoirs can significantly change the stress and pore pressure conditions of subsurface reservoirs from their initial state. The goal of this project, which forms part of an ARC Linkage Project, is to collect and analyse geomechanical data from the Cooper and Eromanga basins in central Australia, which have the potential to be a world leading CCS hub. Whilst stress patterns in this Cooper-Eromanga Basin are well understood, there are considerably fewer constraints on stress magnitudes, which are necessary for calibrating models of geomechanical deformation of reservoir and seal units. The limited data that exist indicate unusually high horizontal stress magnitudes and pore fluid pressures at depths >3 km, which need to be better understood to limit the possibility that CO2 injection may result in induced seismicity. Whilst vertical stress (sv) in wells can be continuously estimated using density logs, minimum (sh) and maximum (sH) horizontal stress magnitudes are usually only determined at limited depths in wells, resulting in the erroneous assumption of linear stress gradients, independent of rock properties. However, recent advances in poroelastic stress theory now permit continuous estimation of total horizontal stresses with depth as a function of elastic and lithological properties. The aims of this PhD project are to a) develop workflows for rapidly generating 1D geomechanical models to enable determination of pre-injection stress and pressure conditions for wells in the Cooper and Eromanga basins; b) quantify how historical injection and extraction has impacted the thermo-mechanical properties of target reservoirs for CO2 storage; and c) develop predictions of how any such changes may impact the likelihood of reservoir deformation such as faulting that may result from CO2 injection.

Eligibility:

Applicants must be Australian or New Zealand citizens or permanent residents of Australia who are acceptable as candidates for a PhD/MPhil degree at the University of Adelaide.

Stipend:

The scholarship will be for 3.5 years and has a stipend of $34,210 per annum.

It is likely to be tax exempt, subject to Taxation Office approval.

Enquiries:

Contact Person: Professor Simon Holford

School/Discipline of: School of Physics, Chemistry and Earth Sciences; Discipline of Earth Sciences

Tel: 08 8313 8035                Email: simon.holford@adelaide.edu.au 

Applying: Expression of interest

Expressions of interest should be submitted to Professor Simon Holford (simon.holford@adelaide.edu.au) by no later than 31st July 2024  with the name of scholarship in the subject heading. Please ensure you include all of the following documents:

• Evidence of Australian or New Zealand citizenship, or Australian permanent resident status (if applicable)
• Degree certificates (testamurs)
• Academic transcripts
• Translations of non-English documentation
• Evidence of English language proficiency
• Curriculum vitae