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Subsea Riserless Light Well Intervention

In January 2016, SapuraKencana Well Services requested well intervention engineering support from NauticAWT Energy Solutions to enable them to carry out a riserless light well intervention (RLWI) for a major operator. The well operator’s tubing retrievable safety valve (TRSV) was inoperative in the closed position, presumed to be stuck rather than defective, thus preventing well flow. The operational scope was to run a HD camera into the subsea well to check the TRSV operation then run an exercise tool on a high force actuator to manually operate, and free, the TRSV. The camera would then be run again to confirm valve operation. 

The Scope

  • Development and review of project specific RLWI programme and operating procedures for Subsea Intervention Device (SID), Intervention Compensation System (ICS), fluid pumping, and slickline / electric-line operations
  • Development of Well Control Emergency procedures for subsea and vessel operations
  • On site Well Intervention Manager providing offshore supervision of SapuraKencana and third party supervisors, technicians and engineers on board SapuraKencana Constructor DP subsea support vessel

The Challenges

  • Extremely limited (well operator specified) timeframe (13 weeks from contract award to vessel departure). This included bringing the equipment out of long term storage and customising it to client specific project requirements as well as creation of all project specific documentation.
  • Integration between Schlumberger’s ReSOLVE High-Force Linear Actuator tool, and Halliburton’s SP-2 TRSV Exercise tool, for the first time globally.
  • Conversion of DP2 dive support vessel into LWI vessel, without removing dive spread.
  • Planning and procedures for 13 contingency toolstrings, with up to 29 separate slickline runs, in addition to “base case” main job programme.
  • Assembling a multi-disciplined well intervention team covering slickline, electric-line, well testing and fluid pumping operations.

Added Value

  • The well was able to commence production at a rate of 50MMscfd.
  • The well operator avoided gas contract penalties as a shutdown of other producing assets was planned.
  • 12 days from field entry to field exit including 1 day standby while well was being beaned up and tested.
  • Saved the well operator having to bring in a Mobile Offshore Drilling Unit (MODU) to workover the well containing a 3400m, 13Cr, intelligent completion string.