In order to carry out the first HPHT field development offshore in Malaysia, learning from experience of HPHT operators in the North Sea, a detailed focus on lifecycle and well integrity aspect has been thoroughly emphasized throughout the well delivery phase. At an initial stage in the project, a locally conventional initial design considered the use of TCP to perforate a 7″ liner and then complete the well in open hole with overbalanced completion fluid. This solution carried several challenges that would have affected the safety of the completion process and the future integrity of the well architecture.

A different approach, in which a fully cased hole well is completed in underbalance and then perforated once the completion is installed and tested is introduced for the first time within PETRONAS. The system allowed the perforation of a 400m HPHT reservoir interval in a single run, by using a dedicated coiled tubing deployment system.

The implementation of this completion philosophy permitted to achieve the following milestones:

  • Completion in underbalanced packer fluid, which enhanced the well architecture by reducing potential production casing failure due to extreme loads in case of tubing leak.

  • The use of inhibited fresh water, provided an effective, alkaline fluid that eliminates the very high potential for corrosion created by heavy, high halides completion brines.

  • Safer way to run the completion in a closed, inflow tested environment.

  • Single perforating run, which allowed for a safer procedure for the deployment of guns. There is no deployment of guns under pressure or under exposure to hydrocarbon.

  • If required, especially in very tight reservoirs, there is the ability to displace the well with N2 immediately after perforating (separate runs for stimulation are not required)

  • As soon as the last gun is out of hole, the well is ready for well testing / clean out / production.

This paper covers the design, QAQC, operational and logistics aspects of the KN Ultra Deep'sCoiled Tubing Conveyed Perforating with a final section covering the challenges and lessons learned that may be used by project teams in the future.

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