Monday 9 December SPE DL Monthly meeting in Carlton Ambassador Hotel:

Mitigating subsurface risks in well abandonment planning

by Wijnand van Eijndthoven (DNV-GL)

Cost reduction in decommissioning gets a lot of attention these days. The decommissioning industry in the Netherlands has set a cost reduction goal of 30%. Well plug and abandonment takes a special place to achieve this goal because it is responsible for the majority of costs and has specific (subsurface) risks.

Understanding well P&A risk is vital for successful abandonment as the task can become very complex with e.g. damaged and corroded wells. Well data, country- and operator specific regulations, and well situation are elements that should be taken into account when planning well P&A. A Seal Performance Assessment (SPA) is regarded essential by DNV GL when performing a risk analysis as part of well P&A planning. Integral part of the assessment is a SPA diagram where well and geology elements are risked for flow against relevant regulations with the help of all available legacy data. This diagram visualizes critical well elements or sections and can be used to develop and verify the abandonment plan.

The well P&A workflow explained in this presentation is a way to understand subsurface risk and achieve significant time reduction while maintain abandonment quality.