A vertically integrated solution for suspended well abandonment

InterMoor specialises in full planning and execution of suspended well decommissioning campaigns. We handle all aspects of the project providing a single source solution for open water well abandonment.

This includes vessel charter, project management, engineering, and onshore and offshore operations from the initial review of well schematics and assistance with regulatory permit applications to the production of final end of well reports. This approach enables our clients to adopt a minimal input hands off approach, 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 and not vessel utilisation.

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 and cost effectiveness when compared to a rig-based alternative. Our goal is to minimise each client’s per well abandonment cost without comprising on safety or harming the environment whilst delivering the best technical solution.

Suspended well abandonment tool (SWAT)

Our approach is based on combining a cost-effective vessel-based platform with specialist bespoke rigless abandonment equipment to deliver a fit for purpose solution. Our specialist team working with sister company Claxton Engineering utilise SWAT to deliver a cost-effective solution to suspended well P&A.

The SWAT system is designed to permit rigless perforation, circulation and cementation of multiple casing annuli and has been used to abandon over 115 Category 2 wells (SS 0-1-1 as per OGUK guidelines) in the UKCS.

SWAT is deployed through the moon pool of a light construction or anchor handling 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 back to on-board storage tanks. This is followed by the placement of the required cement plugs in the well bore and annuli. The system is pressure rated to 5,000psi.

With the introduction of a SWAT Extension Module, developed in response to industry demand, barriers can now be set at any depth required. This technology enables barriers to be set on a firm base and minimise cement contamination. The deepest cement plug set to date is 2,800 ft. BML.

SWAT is an exceptionally versatile system and can be configured to suit all types of suspended subsea open water wells. For mudline system wells, the Twin Lower Pressure Packer (Twin LPP) variant of SWAT is utilised in the same manner. Both equipment spreads are operated by Claxton and exclusively utilised by InterMoor.

After intervention operations are complete, the wellhead is then severed below the mudline using specialist abrasive cutting technology before being recovered to the vessel for disposal onshore.
As part of its vertically integrated project approach, InterMoor manages all aspects of the well abandonment from planning, engineering, offshore execution and project close out.
In well abandonment operations, our team ensures 100% equipment redundancy by carrying one complete spare SWAT system on deck during offshore operations.

Benefits of the SWAT system

  • Deployed from a cost-efficient light construction vessel, removing the requirement for a drilling unit or well intervention vessel.
  • A fully diverless system remotely controlled and operated from surface via dedicated umbilical.
  • A one-stop solution for final environmental cement barrier across all annuli and the wellbore to any depth required.
  • Fitted with a remote emergency disconnect mechanism which can be activated on deck to allow the vessel to move off location while pressure integrity of the well is maintained.
  • Class leading, industry recognised and used without a single reportable environmental incident for over 20 years.

Experience

The InterMoor decommissioning team has an unrivalled track record in suspended well abandonment successfully completing 134 wells since 1996:

  • 17 wells were Category 1 (SS 0-0-1)
  • 56 wells were Category 2.1 (SS-0-1-1)
  • 58 wells were Category 2.2 (SS 0-1-1)
  • 3 wells were Category 2.3 (SS-0-1-1)

Recent wells completed

Well No Depth Wellhead Vessel Diver/
Diverless		 Year Cat Outline Procedure
42/28d-13z 170 ft. Dril-Quip MS15 MLS Island Valiant D/L 2019 ML1.0 Sever and recover 30” Conductor below the mudline
42/28d-12 172 ft. Dril-Quip MS15 MLS Island Valiant D/L 2019 ML1.0 Sever and recover 30” Conductor below the mudline
48/10a-15y 101 ft. 13 5/8” Vetco SG-1 (Torus II profile) Island Valiant D/L 2017 SS2.1 Perforate annulus to recover OBM, cement single annulus and wellbore from 2,100ft – 1,294ft BML.  Sever three casing strings and recover wellhead
48/10b-10 66ft. 13 5/8” Vetco SG-1 (Torus II profile) Island Valiant D/L 2017 SS2.1 Perforate annulus to recover WBM, cement single annulus and wellbore from 2,800ft – 2,300ft BML.  Sever three casing strings and recover wellhead
110/3b-6a 77ft. 13 5/8” Vetco SG-1 (Torus II profile) Island Valiant D/L 2017 SS2.2 Perforate two annuli to recover WBM, cement two annulus and wellbore,  Sever three casing strings and recover wellhead
44/28a-6 209 ft. Drill-Quip MS15 MLS Island Valiant D/L 2017 ML2.2 Recover two internal threaded TA caps. Perforate two annuli to recover WBM.  Cement two annuli and wellbore from 550ft – 30ft BML.  Sever and recover single 30” conductor.
21/28a-10z 290 ft. Drillquip SS10 Island Valiant D/L 2015 SS2.1 Cement single annulus and wellbore at 2126 ft BML, sever and recover wellhead (used SWAT extension module).
21/28a-2 286 ft. Vetco 10Kpsi CIW Hub Island Valiant D/L 2015 SS1 Cement wellbore at 2400 ft BML using deep set delivery hose stinger, sever wellhead and recover complete with PGB (used SWAT extension module).
21/28a-9Y 288 ft. Drillquip SS10 Island Valiant D/L 2015 SS1 Sever wellhead and recover.
21/29d-11z 286 ft. Drillquip SS10 Island Valiant D/L 2015 SS1 Sever wellhead and recover.
21/20a-5 311 ft. Drillquip SS15 Island Valiant D/L 2015 SS2.1 Recover OBM, cement single annulus and wellbore, sever wellhead and recover wellhead complete with PGB.
16/12a-9 415 ft. Vetco SG5 Island Valiant D/L 2015 SS2.1 Cement single annulus and wellbore, sever wellhead and recover wellhead complete with PGB (used SAWT extension module lower wiper ball ahead of cement plug)
16/12a-13 417 ft. Vetco SG5 Island Valiant D/L 2015 SS2.1 Recover OBM, cement single annulus and wellbore, sever wellhead and recover wellhead complete with PGB.
16/12a-20 420 ft. Drillquip SS10 Island Valiant D/L 2015 SS2.1 Recover OBM, cement single annulus and wellbore, sever wellhead and recover wellhead complete with PGB.
22/22b-5z 304 ft. Vetco MS700 Island Valiant D/L 2015 SS2.2 Recover OBM, cement single annulus and wellbore, sever wellhead and recover wellhead complete with PGB. (used SAWT extension module lower wiper ball ahead of cement plug).
16/12a-5 414 ft. Vetco SG5 Island Valiant D/L 2015 SS2.2 Cement two annuli and wellbore, sever and recover wellhead complete with PGB (used SAWT extension module lower wiper ball ahead of cement plug).
2/1-11 224 ft. Dril-Quip SS-15 Island Constructor D/L 2014 SS2.1 Recover OBM from annulus, cement single annulus and wellbore.
2/1-9A 218 ft. Dril-Quip SS-15 Island Constructo D/L 2014 SS2.2 Recover WBM from both annuli, cement both annuli and wellbore

Example of a multi-operator campaign

FAQ’s on rigless well abandonment

Well abandonment – InterMoor experience list