Lessons form market analysis data showed different model from actual.
A well-defined decommissioning scope along with input from the decommissioning studies and market conditions are key to building up a robust cost estimate. The cost estimates should take into account required operational support and related costs (i.e. dedicated support vessel, etc.) for each phase as this was not considered under the platform support estimate nor it is identified in the Oil and Gas UK guidelines. In the estimate, platform support costs were assumed to be reducing post CoP (Cessation of Production), but the opposite was realised, with PoB levels increased during the completion of the EDC (engineering down and cleaning) and Well P&A works.