Project Management

Throughout the various elements of a decommissioning project, operators will need a core team to manage the day-to-day activities. This core team will fluctuate over…

Post CoP Running Costs

When a producing facility is no longer economically viable, operators can apply to the OGA for cessation of production (CoP). Post-CoP OPEX refers to operational…

Well Decommissioning

Well decommissioning is the permanent isolation of any rock formations with flow potential and the restoration of a seabed to its previous status. There are…

Facilities / Pipelines Make Safe

In simple terms, oil and gas installations are in place in order to extract hydrocarbons from a reservoir and then transport them elsewhere to be…

Topsides Preparation

Once all sources of energy have been isolated, the topsides can be prepared for removal. The ‘topsides’ refer to the facilities which sit on top…

Topsides Removal

During a decommissioning project, all topsides must be removed. There are three principal methods for achieving this: • Single-lift – Using a large lift vessel…

Substructure Removal

Once the topsides have been recovered to shore, the removal of the substructure can take place. Substructures vary considerably in terms of their shape and…

Onshore Recycling / Waste Management

Once topsides and substructures are transported to shore they are managed under the waste hierarchy, considering re-use, recycling or disposal. Owners of oil and gas…

Subsea Infrastructure Removal

When a pipeline, cable or umbilical has reached the end of its useful economic life, it must be decommissioned. In the UK, pipeline decommissioning is…

Site Remediation

Once the decommissioning of the topsides, substructures, pipelines and associated subsea infrastructure have been completed, operators are required to ensure that the seabed is made…

Post Decommissioning Monitoring

Monitoring programmes are required for any infrastructure that is left in place under the Decommissioning Programme. Surveys will be conducted to check the status of…

Making Safe

‘Making safe’ of facilities includes cleaning, freeing equipment of hydrocarbons, disconnection and physical isolation, and waste management. ‘Making safe’ of pipelines involves depressurising them and…

Environmental Assessment (EA)

An assessment of the environmental impacts for the activities planned to take place during the decommissioning workscope.

Work Breakdown Structure (WBS)

The WBS shows all elements of a typical decommissioning project and forms the basis for calculating decommissioning expenditure during different stages of the process.

Decommissioning Programme (DP)

The Petroleum Act 1998 requires owners to set out the measures to decommission disused installations and/or pipelines in a decommissioning programme. A decommissioning programme must…

Comparative Assessment (CA)

Used to compare options, examine differences and identify the ‘most preferred’ option in the development of decommissioning programmes for: a) All installations for which derogation…

Asset Stewardship Survey

A survey run by the OGA which creates a single source of robust data. It is used to inform stewardship reviews and provide meaningful insights…

CoP

Cessation of Production