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Design for decommissioning
Draft Index for review by the Joint Industry project. The final page will be completed soon with many additions
Statement of objectives
The D4D Database provides feedback from late life and abandonment operations. It provides practical guidance to engineers when designing new facilities or modifying existing facilities
The challenges and issues encountered at the end of a facility's life may not be foreseen or correctly considered during the design phase. This lack of attention can make the eventual decommissioning work more technically challenging and costly. The purpose of the database is to identify decommissioning issues based on real industry lessons learnt and translate these into potential solutions which could be implemented in future designs
History of JIP
Work group: formed in Aug 2016 with thirteen organisations
Initial project scope: boundaries identified – i.e. subsea only
Demonstrated economic value: examined the influence of decommissioning costs in the whole asset lifecycle
Structure for database: defined for use by Lead Design Engineers
Database populated: input from decommissioning community as follows
• One on one interviews lasting about one hour with all members of the JIP gaining their experience in the UKCS, Africa, Norwegian and Australian waters. • Attendance at the decommissioning conferences o Decom North Sea, o Oil and Gas UK, o Norwegian Petroleum Forum, o SE Asia Kuala Lumpur, o SPE workshop Kuala Lumpur o Decom World Houston o Decom World Aberdeen • Review of the Lessons learnt of BP when doing decommissioning projects in the North Sea over the last five years • Reading the technical press (Offshore Engineer and SPE journal during the last two years)
Industry guidelines: started preparation to integrate findings and recommendations into the conceptual and FEED phases of the lifecycle
Decommissioning cost matrix
The guidance note maps the decommissioning requirements back to the infrastructure components in a series of design considerations.
It will provide a framework to incorporate decommissioning requirements into the design process and include a set of templates and checklists
The relative cost of decommissioning each component of a subsea development has been assessed and is listed on the table.
A series of activitiies are needed to decommission and remove each component. These activities have been listed in the table. The activities are taken from the list of decommissioning activities published in the Oil and Gas UK guidelines. The cost of an activity to decommission a component of the subsea development has been assessed as being
- High (coloured red),
- Medium (coloured yellow)
- Low (coloured blue)
Decommissioning activites that are not applicable to a component have been left blank
When to incorporate decommissioning in design
Decommissioning shuold be incorporated in the design during the Define or FEED stage of the project. This is the stage of a project where the major design criteria are written in to the Basis of design and design specifications. After this stage the project team has moved to the Execute stage and Change control is rigoursly enforced. Modifications to the design to assist or ease decommissioning will not meet the criteria for the change control committee.
Before the Define or FEED stage the project team will be studying several options to select the best solution to develop the field. There is not enough definition of the options to consider design for the final decommissioning. The decommissioning specialist should provide an estimated cost of decommissioning and remvoing each option for the project cost estimates and list the removal options and any issues for the regulators and other stakeholders.
Database of lessons learnt and design guidance
Rigid export pipelines
Manifold and riser bases
The cost of decommissioning can affect the project economics. Project economics use the Net Present Value calculation. This calculation needs the Capex, Opex, Decommissioning Cost or Abex, tax rebate and income from sales of oil and gas. Economic analysis has been completed for the Clyde project reported in the Offshore Europe conference in Aberdeen in 2017 (Design for Decommissioning)
Stuart Martin Stuart.Martin@ardent.com
Caroline Laurenson Caroline.Laurenson@xodus.com
Alan Stokes Alan.Stokes@advisian.com