Introduction

The Australian Cooperative Research Centre for Greenhouse Gas technologies (CO2CRC) is conducting a CO₂ injection project in Australia.  Known as the CO2CRC Otway Project this is the first project to inject and store CO₂ under Australian conditions.  The project, which is of intermediate scale, will inject approximately 100,000 tonnes of CO₂ over a 2 year period. The CO₂ is be extracted from a nearby natural accumulation via an existing production well then transported via pipeline and injected into a depleted gas field (called the Naylor gas field).  In support of the injection project, a detailed monitoring programme has been developed by the CO2CRC for the Otway Project. One year since the injection and monitoring operations commenced, the IEA Greenhouse Gas R&D Programme (IEA GHG) was invited by the CO2CRC to undertake an independent expert annual review of the Otway Project monitoring programme.

An international team of experts (from Canada, France, UK and USA) was assembled by IEA GHG which reviewed the monitoring progress for the Otway Project.  The Otway Project is considered to be an important, first of its kind, CO₂ injection activity into an onshore depleted gas reservoir.  The Otway Project therefore provides important experience in monitoring this type of reservoir, which is likely to be widely used globally for CO₂ storage.  The Otway Project is also interesting in that it is a composite onshore demonstration project that includes many key aspects of CO₂ storage i.e. CO₂ production, transportation, injection, and storage, albeit at a small scale, in a single demonstration project.  A further strength of the project is considered to be CO2CRCs ownership of the production and injection wells which will allow the research programme to proceed unencumbered by external operational requirements which should allow the Otway Project to deliver on range of research objectives.

Whilst this review does not correspond to any particular project milestones, it shows the success to date in the project implementation and monitoring methodologies and results. It is clear that the monitoring work gives an indication that the reservoir is performing according to predictions. Despite the challenges associated with a depleted gas reservoir environment with a small diameter monitoring well the monitoring approach has shown significant success. This intensive and integrated effort is a first demonstration of feasibility for a depleted gas reservoir in Australia and represents a significant contribution to world knowledge.

Conclusions

An international team of experts has reviewed the monitoring plans and programme for the CO2CRC Otway Project.  The Otway Project was considered to be an important first of its kind, CO₂ injection activity into a closely monitored onshore depleted gas reservoir.  The Otway Project should therefore provide important experience in monitoring this type of reservoir, which is likely to be widely used globally for CO₂ storage.  The Otway Project is also interesting in that it is a composite onshore demonstration project that includes nearly all the aspects of CO₂ storage i.e. CO₂ production, transportation, injection, and storage, albeit at a small scale, in a single demonstration project.  A further strength of the project is considered to be CO2CRCs ownership of the production and injection wells which will allow the research programme to proceed unencumbered by external operational requirements which should allow the Otway Project to deliver on range of research objectives.

It is clear that significant advances have been made in implementing the initial stages of the monitoring programme. This review does not accord with any specific project milestones and as such in most cases only “preliminary results” are reported. There has been much groundwork, planning and deployment of monitoring equipment and recording useful data. This, and the lessons learned therein, should not be underestimated. Thus, the potential value and effectiveness of much of the monitoring effort has yet to be fully realised.