Geo-engineering and Economic Assessment of a Potential Carbon Capture and Storage Site in Southeast Queensland, Australia

Abstract

Abstract This paper presents geo-engineering and economic sensitivity analyses and assessments of the Wunger Ridge flank Carbon Capture and Storage (CCS) site. A numerical reservoir simulation examines injection rates ranging from 0.5 to 1.5 million tonnes of CO2/year. Primary factors affecting the ability to inject CO2 include permeability, formation fracture gradient, and multiphase flow functions. Secondary factors include the solubility of CO2 in the formation brine, injection well location with respect to the flow barriers/low-permeability aquifers, model geometry including faults, grid size and refinement, and injection well type. Less significant factors include hydrodynamic effects. The economics are assessed using an internally developed techno-economic model. The model optimises the CO2 injection cost based on geo-engineering data and recent equipment costs. The overall costs depend on the initial costs of CO2 capture and on source-to-sink distances and their associated pipeline costs. Secondary cost variations are highly dependant on fracture gradient, permeability and CO2 injection rates. Depending on the injection characteristics, the specific cost of CO2 avoided is between A$30 and A$44 per tonne.