Geological Storage of Carbon Dioxide (CO2CRC) Project

This project is Geoscience Australia's contribution to the core program of the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC). CO2CRC is one of the world's leading research organisations developing technologies and the science required for carbon dioxide (CO2) capture and geological storage (CCS). At their research site in south west Victoria, CO2CRC has injected CO2 deep underground into firstly, a depleted gas reservoir, and more recently a saline formation. In plans for the third stage of the project, commencing in 2016, researchers are studying how CO2 interacts with geological faults and developing less expensive and innovative ways of monitoring the CO2, as it moves and stabilizes underground.

The CO2CRC storage program addresses a wide range of questions relating to areas such as COCO2 monitoring, the nature of deep saline formations and rock mechanical behaviour in storage formations and fluid-rock interactions imposed by the introduction of CO2.

Geoscience Australia researchers have been involved with CO2CRC since 2003 and currently lead the following projects:

Fault seal integrity

This project aims to develop a workflow to provide the foremost capability in understanding the mechanical properties of fault zones. Properties that affect the stability of faults and also the hydraulic behavior with respect to CO2 are fault cohesion and friction, and also fault permeability and porosity, as these hydraulic properties can exert an important control on fluid pressure evolution and therefore fault strength. This project will develop a petrophysical and rock mechanical workflow in which various measured mechanical properties of rock can be used to characterise faults within or near regions of CO2 storage. The measured mechanical data will also be used in conjunction with wireline and drilling data to effectively generate transforms for mechanical properties. It will be especially interesting to apply these transforms to data from CO2CRC's CRC-1 well at their Otway site, which possesses wireline data through a fault zone.

Results of fault modelling conducted at the CO2CRC Otway Project. The figure shows a large fault in the background and a smaller synthetic fault in the foreground. The smaller fault, the Naylor south splay fault, is color coded by the fluid pressure increase required to theoretically perturb the fault during CO2 injection (pressures in MPa). The results show that significant pressure increases are required before any movement would occur on the fault

Results of fault modelling conducted
at the CO2CRC Otway Project

Specific tasks will include:

  • Triaxial testing of typical specimens to ground-truth basic strength parameters of rocks within the Paaratte Formation.
  • Scratch testing of core including fractured domains to resolve the fine scale mechanical variations and develop the multi-variate relationships to various well logs.
  • Development of limited "stick-slip" experiments to characterise the static and dynamic frictional properties which are controlling factors in the generation of micro-seismicity.

Prediction and verification of shallow CO2 migration

The project will aim to characterise the near surface geology at the CO2CRC Otway site and evaluate, through modelling, the geochemical interaction and migration of CO2 in the karstic Port Campbell Limestone. The project seeks to simulate how CO2 leakage up a well bore into a shallow aquifer could be detected, predict how the CO2 would move, and what the impacts on groundwater chemistry might be.

One of 988 wireless geophones used during the high resolution 3D seismic survey

One of 988 wireless geophones
used during the high resolution
3D seismic survey

The objectives of the project are:

  • Through seismic, and resistivity and LIDAR surveys, identify structures in the near surface at the Otway site that could potentially provide leakage or higher permeability CO2 pathways. Develop an increased understanding of the Port Campbell Limestone permeability through groundwater pumping/slug tests and wireline logging of nearby groundwater monitoring wells.
  • A focus on geochemical modelling and monitoring, as it will give us the opportunity to interpret the abundant Stage 1 groundwater monitoring data and set limits on the effects of leakage into the Port Campbell aquifer. This would provide an opportunity to assess the effectiveness and sensitivity of near surface groundwater monitoring.

Geoscience Australia researchers also contribute to the following projects:

  • Otway assurance monitoring - annual soil, gas, groundwater and reservoir sampling across the CO2CRC Otway site to test the capabilities of long-term assurance monitoring over a CO2 storage project.
  • Otway Stage 3 - Geomechanical characterisation of the Paaratte Formation, the target saline formation for CO2CRC's in-field project which aims to develop a permanently deployed subsurface and cost-effective real-time monitoring solution for industry.