Following Australia's first operator-supported offshore decommissioning liability assessment, several measures have been identified to reduce cost based on the insights generated from the asset databases.
By adjusting the work breakdown structure of the costed decommissioning database, a quantum of reduction that can be targeted for key measures has been estimated:
- A 15% saving on overall liability can be achieved by limiting activities to preparation, disconnection, cleaning and site remediation.
- A combination of three key factors namely, a dedicated P&A workgroup, application of a technical limit approach and application of new technology would provide an estimated 10% saving on overall liability.
- The use of a re-floating and towing method in place of a heavy lift vessel for large jacket substructures holds a potential cost saving opportunity of 4%.
- The identification and development of designated ports and marine facilities on the West coast to handle large structures and marine spreads has the potential to reduce the overall decommissioning liability by 4%.
- A campaign approach across multiple assets is required to spread the high Wells P&A working group- equiv. drill to limit concept new technology cost of equipment mobilisation across a portfolio of compatible decommissioning projects, with a cost reduction of 3% seen as a reasonable target based on multiple campaign opportunities nationwide.
- The opportunity to leave such sub-structures (5 in Australian waters) in place represents a cost saving of 0.5% on the overall liability.
In order to maintain continuity of savings on the liability, effective industry-wide knowledge sharing should be ensured, failure of which will risk sub-optimal cost reduction outcomes.
