Rigless Well Abandonment Services

Well Head on deck

A Turnkey Solution

InterMoor specializes in the planning and execution of turnkey suspended well decommissioning campaigns. This includes vessel charter and project management of all onshore and offshore operations from the initial review of well schematics to the production of end of well reports. This approach requires minimal input from clients thereby allowing them to focus on their core operations.

We are proud of the fact we are not a vessel owner which means we can focus 100% of our efforts on the needs of the client not our vessel utilization rate.

Commercially Efficient Campaigns

Whether as part of a multi-operator or standalone campaign, our team is experienced in planning commercially efficient solutions to provide clients with significant benefits in terms of cost-effectiveness when compared to a rig based alternative.

Suspended Well Abandonment Tool (SWAT)

Our core business is vessel based suspended well decommissioning where we utilize sister company, Claxton Engineering's, SWAT system to deliver a cost effective solution to well P&A.

The SWAT system is designed to permit perforation, circulation and cementation of multiple casing annuli and has been used to abandon over 80 Category 2 subsea wells in the UKCS.

SWAT is deployed through the moon pool of a light construction vessel and landed on the wellhead casing hanger. The tool is then used to perforate the internal casing strings in order to allow circulation and recovery of the annular drilling fluids (i.e. OBM and WBM) back to the vessel storage tanks. This is followed by the placement of the required cement plugs in the well bore and annuli. The system is field proven and is pressure rated to 5,000psi.

With the introduction of a SWAT Extension Module, developed in response to industry demand in 2015, barriers can now be set at any depth required. The deepest cement plug set to date is 2400 ft BML.

After intervention operations, the well head is severed using specialist abrasive cutting technology before being recovered to the vessel and later disposed of onshore. OIS also provides this cutting and recovery service, using project specific fit-for-purpose equipment, as part of its turnkey approach.

SWAT is an exceptionally versatile system and can be configured to suit different categories of open water wells.

In well abandonment operations our team ensures 100% redundancy by carrying one complete spare system on deck during offshore operations.

 For shallow water mudline well applications a variant of the SWAT system is used – the Twin Lower Pressure Packer (Twin LPP) system, which is also owned by Claxton. Both systems are utilized exclusively by InterMoor.

Benefits of the SWAT system

  • SWAT is deployed from a light construction vessel, removing the requirement for a costly drilling rig or heavy well intervention vessel.
  • SWAT is a fully diverless system which has no permanent riser and is fully controlled from surface.
  • SWAT provides a market leading one-stop solution to placing the final cement barrier across all annuli.
  • SWAT has a disconnect mechanism which can be activated in the case of an emergency to allow the vessel to move off location while pressure integrity of the well is maintained.
  • SWAT is industry proven and has been used without a single reportable environmental incident.


In the decommissioning sector, the team has an unrivalled track record in the successful decommissioning of suspended wells and has completed 128 wells since 1996 in the North Sea:

  • 15 wells were Category 1
  • 56 wells were Category 2.1
  • 54 wells were Category 2.2
  • 3 wells were Category 2.3

Wells completed in 2014 & 2015

Example of a multi-operator campaign

FAQs on Rigless Well Abandonment

For any enquiry, please contact Sales.UK@intermoor.com

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