EnergyAustralia – Assessment of gas storage field performance

Overview

RISC has provided regular technical support and asset evaluation to EnergyAustralia, owners of the Iona gas storage field in Victoria from 2002 to date, culminating is a vendor due diligence report to support the sale of the asset in 2015 for A$1.8 billion.

Our approach

Our support started with a thorough subsurface evaluation that included data review, seismic interpretation, 3D geological and dynamic modelling, history matching and evaluation of further development options. The 2009 geological model has been used without modification for over seven (7) years of gas storage operations, and continues to provide a reliable basis for forecasting and modelling.

More recently RISC has quantified the working storage volume, the maximum allowable injection volume to prevent over filling the reservoir, and the minimum volume required in the reservoir to still meet contract capacity requirements. These proved to be functions of the gas injection and withdrawal rates due to delays in aquifer response.

RISC also reviewed the facilities and surface operations to quantify the potential value of compressor, de-bottlenecking and operating options. Through close liaison with the owners, we identified bottlenecks to further gas storage contracting and identified further commercialisation opportunities.

Outcome

Our assessment enabled EnergyAustralia to:

• Quantify the working storage volume and their ability to fulfil existing and develop additional storage contracts.
• Quantify field deliverability versus volumes delivered. Evaluate the benefit of additional wells and re-completion of existing wells to improve gas injectivity and deliverability.
• Extend field operations to test field deliverability and working storage volumes.
• Quantify the potential benefit of debottlenecking opportunities.
• Audit the gas inventory (i.e. stored volume).
• Demonstrate the value and potential of the asset both internally and externally.
• Realise the full asset value through a dataroom sales process and A$1.8 billion sale price.

Media links:
QIC to buy EnergyAustralia’s Iona Gas Plant for $1.78b – www.afr.com
CLP Holdings sells Iona gas plant to QIC Ltd for $1.78bn – www.theaustralian.com.au