Abstract
The Gorgon Project is a major LNG development to be based in Northwest Australia. Gas will be produced from several offshore gas fields located in the Greater Gorgon Area with processing facilities to be located on Barrow Island. The reservoir fluids of several of the fields contain carbon dioxide (CO2) which will be extracted from the produced gases prior to liquefaction into LNG. The Gorgon Joint Venture participants have proposed to geologically dispose of the produced reservoir CO2 from the gas processed at the Barrow Island LNG plant.
The CO2 injection project was extensively documented and subjected to public comment as part of the Gorgon Project Environmental Impact Assessment Process. Following this process the WA Environmental Protection Authority found that the environmental risks associated with the CO2 injection project were acceptable and recommended that CO2 injection must proceed as an integral component of the Gorgon Project.
The target formation for geological disposal of this carbon dioxide is the Dupuy Formation, a Jurassic saline reservoir, deep beneath Barrow Island. The evaluation of the Dupuy Formation for the disposal of carbon dioxide was focused on characterising the reservoir and narrowing subsurface uncertainties not addressed by legacy oil exploration and development. Data acquisition was targeted to reduce major subsurface uncertainties including a seismic pilot to assess acquisition methods (including 4-D seismic) and an extensively evaluated appraisal well. Robust geological description, hydrodynamic, static and dynamic reservoir models have been used to gauge the impact of CO2 injection on development decisions. Key drivers for this development have been maximising per well injection of CO2 and ensuring containment of CO2 within the reservoir. Through effective subsurface and economic evaluation, a phased and flexible development plan for CO2 disposal has been developed to meet these objectives.
