Decommissioning & reuse Cessation of Production (CoP) and Post CoP activities
Decommissioning of wells, installations and pipelines is subject to a set of stringent national and international regulations. Overall, the obligations arising from these regulations aim at leaving wells permanently closed off and the installations completely removed, both in the safest way possible.
After cessation of production, the platform is brought into a hydrocarbon-free state by cleansing of the platform and flushing of the pipelines. The reservoir itself is fully isolated by suspension of the wells. The production platform is brought into a 'warm stack modus'.
Well plug & abandonment P&A activities - an integral part of our work
The next step in the decommissioning process covers the final well plug and abandonment activities, usually done with a drilling rig. After completion of this processm the platform finds itself in 'cold stack modus'. In order to create commercial and operational synergies (scope benefits, implementation of lessons learned), WINZ prefers to make use of a campaign-based approach.
Well abandonment means restoring the natural integrity of the formation that was penetrated by the wellbore and concerns the isolation of rock formations that have flow potential.
Platform reuse or removal Dismantling and/or disposal activities
The final step is either the reuse or the removal of the platform (topside and jacket), followed by dismantling and onshore disposal.
In line with the waste hierarchy, reuse of (a part of) an installation is firstly looked at in the order of preferred decommissioning options. Several topsides (the top part of a production platform) of WINZ installations have been relocated and reused in the past and there may be opportunities to do so in the future. Where reuse is not an option, installations (topside and jacket) will be brought to shore for further disposal.
In case no reuse of reservoirs or facilities are foreseen, the pipeline(s) will be disconnected from the platform or well location. The pipeline ends will be rock dumped.
Decom and reuse track record Activities at the heart of our business
Wintershall Noordzee plugged and abandoned its first wells and removed its first production platform in 1988. In the years thereafter, decommissioning was executed on a case by case basis. In 2019 however, it was decided to execute decommissioning activities in a campaign-based manner. In 2021, the company strated Phase I of the WINZ Decom Campaign with the execution of plugging and abandoning (P&A) of the P9-A and P9-B subsea wells, as part of a 24 wells P&A scope with the Swift-10 drilling rig. One year later, the execution of Phase II was approved, including the P&A of 17 wells and the removal of 8 offshore installations. This phase was subsequently succeeded by Phase III with the plugging and abondonment of another 18 wells and the removal of an additional 3 platforms.
From 1988 on, Wintershall Noordzee has P&A’d 105 wells, of which 46 since the start of the WINZ Decom Campaign in 2021. In total, 26 production platforms have been removed of which 9 have been reused. Since 2021, 7 platforms have been removed.
In 2024, the well P&A scope includes another 3 platform locations and approximately 10 Mud Line Suspension (MLS) wells. These wells have never produced, but need final P&A according to the current legislation. Since 2021, 7 MLS wells were P&A’d, 10 willbe P&A'd in 2024 and another 5 are scheduled for 2025.
Before the end of 2024, 5 platforms will have been removed, of which the first was brought to shore in May. Three main platforms are ready for removal after 2024 and subject to tendering.
News
November 2024
In accordance with the provisions of the Petroleum Act 1998, Wintershall Noordzee B.V. has submitted, for the consideration of the Secretary of State for Energy Security and Net Zero, the draft Decommissioning Programmes for the facility and pipelines associated with the Wingate Field. It is a requirement of the Act that interested parties can be consulted on such decommissioning proposals.
The Wingate Field is located in blocks 44/18d, 44/19f, 44/23f and 44/24b of the Southern North Sea, approximately 180 km east of Scarborough. The Wingate Field was developed as a Normally Unmanned Installation with produced gas exported to the host facility D15-FA-1 located in Dutch territory.
The facilities covered by the Wingate Decommissioning Programmes are:
- The Wingate platform
- All subsea pipelines within the UKCS associated with the Wingate field
As part of the public consultation on the Decommissioning Programmes, the following documents are available for consultation:
Comments on the Decommissioning Programmes should be submitted by email to compliance.winz@wintershall.com before the consultation closes on 22 December 2024. Submissions should state the grounds on which the representation is made.
October 2024
In October 2024, WINZ successfully completed the removal of platforms P12-SW, P6-A, L5-B, Ravn and D12-A. Good cooperation with Scaldis Salvage and Marine Contractors resulted in a safe, successful and cost-effective project. Final disposal will take place at Scaldis Salvage and Marine Contractors and it is expected that the full scope of decommissioning will be completed by Q3 2025.
WINZ would like to thank all colleagues, partners, contractors, sub-contractors and stakeholders involved in the project for their efforts and support!
May 2024
In May 2024 the HLV Gulliver of Scaldis Salvage and Marine Contractors set sail to the WINZ P12-SW platform to remove the topside first and bring it to Hoondert Services and Decommissioning B.V. in Vlissingen. Within 1 week the topside was prepared, lifted and brought to shore and a week later the P12-SW jacket was safely landed on the Hoondert quay. The first platform as part of the 2024 removal campaign of 5. Soon removal preparations at P6-A will start, followed by L5-B, Ravn and D12-A.
