In November 2013 our specialists successfully completed their 17th multi-operator well suspended abandonment campaign in the North Sea.

A total of six subsea wells were abandoned on behalf of Nexen Petroleum UK, Talisman Sinopec Energy UK and Hess Services UK.

The multi-operator model, which enables operators to share project costs, combined with the rigless approach, provides a cost-effective way to decommission non-revenue generating assets and comply with Oil and Gas UK guidelines when compared to a rig based alternative.


  • Sourcing and reviewing well-specific data to identify assets suitable for vessel-based abandonment
  • Performing initial well reviews
  • Appointing and managing all subcontractors
  • Supporting completion of environmental data related to abandonment operations, including: OPEP (Oil Pollution Emergency Plan), PON 5 (Application to Abandon a Well), PON 15f (Permit to use/discharge chemicals during well abandonment) and Marine Coastal Access Act License
  • Contracting with multiple operators involved in the campaign
  • Developing detailed operational procedures
  • Vessel charter and management
  • HSEQ support
  • Performing all project reporting and accounting
  • Preparing end of well reports


The offshore operation was conducted over two phases from a chartered Multipurpose field and ROV Support Vessel (MRSV), the Siem Stork.

Phase 1: the SWAT system, owned by sister company Claxton Engineering (Claxton), was deployed through the vessel’s moon pool to set cement plugs across the casing annuli of the wells

Phase 2: abrasive severance of the wells in water depths which varied from 200-500ft and safe disposal of all recovered subsea structures and waste materials.

Our flexible approach was again demonstrated this year as adverse weather conditions occasionally meant the vessel crane could not operate safely, resulting in initial project activity moving to Southern blocks in order to best work around the weather window without compromising operational efficiency.

Well list

Operator Well Depth Well Category Abandonment Type
Nexen Petroleum UK 15/22-18 477 ft. 2.2 Intervention and Severance
Talisman Sinopec Energy UK 30/3a-1 249 ft. 2.2 Intervention and Severance
Talisman Sinopec Energy UK 15/23-8 478 ft. 2.1 Intervention and Severance
Talisman Sinopec Energy UK 15/23a-9 470 ft. 2.1 Intervention and Severance
Hess Services UK 39/2-2z 233 ft. 1 Severance only
Hess Services UK 31/26A-a 12z 231 ft. 1 Severance only