CO2-water-rock impacts to groundwater during CO2 geological storage with impurity gases

Speaker: Dr Julie Pearce

Abstract: Carbon dioxide geological storage is one option to enable Australia to reach net zero. Several carbon storage demonstration sites are undergoing feasibility studies and environmental impact assessment internationally and in Australia. Very recently CO2 storage in the Surat Basin gained a lot of media and political attention – the QLD government has now put a ban on CCS in the geographical extent of the QLD Great Artesian Basin (and below it). The reservoir that was being assessed is in a deep (~2300 m), brackish, unpotable part of the Precipice Sandstone. However, the broader formation is an aquifer of the GAB, therefore stakeholders were sensitive to potential environmental impacts. The previous demonstration site that underwent assessment was further north in the shallower part of the Precipice Sandstone (~1200 m). In that Glenhaven site the West Wandoan 1 well was drilled for the feasibility study, and the reservoir had fresh groundwater. This presentation details part of the experimental and field sampling components of the underlying research, including CO2-water-rock experimental geochemical reactions, metal mobilisation to groundwater predictions, and creation of a reactive transport model.

Bio: Dr Julie Pearce has international experience in the UK, Japan, and Australia on interdisciplinary projects, and is currently an ARC Mid-Career Industry Fellow at the Gas and Energy Transition Research Centre and School of the Environment at the University of Queensland. Pearce is an expert on gas-water-rock interactions with a focus on CO2 geological storage. She is also working on field-based techniques for measurement of dissolved gases and understanding potential methane leakage processes and interaquifer connectivity through geochemical and isotopic techniques. Julie is collaborating in research projects with the gas and CO2 storage industries and has provided expert opinion to the Government.