The technology innovation applied and lessons learned acquired in the Temsah field PLEMs change over project further TNW blow out emergency, occurred in August 2004, bring to analyze a real case study for production optimization while operating on in service facilities subsea.

Following the Temsah NW accident, it was of paramount importance to recover the Temsah and Akhen fields' production with a fast track redevelopment project. To match a challenging production restart up (6 months for Akhen) temporary gas and condensate PLEMs were installed in the field. Such PLEMs, procured in 2 months and made of materials (piping and valves) not suitable for subsea applications, allowed operability initially up to one year and extended up to four.

The final Plan of re-Development, as conceived by Petrobel, allowed both PLEMs change over with limited impact on production compared with the original plan.

Smart plugs solutions have been applied in the condensate PLEM replacement while subsea hot tapping and stoppling have been implemented all at once in the gas PLEM replacement.

Due to the water depth of 85 m the offshore activities, in both cases, have been executed in saturation diving mode, operating on different sealines size, from 6″ up to 32″, with the aim to avoid the sealine flooding minimizing the impact in the production facilities.

The reconsideration of the overall Temsah field development with improvements in the subsea facilities allowed not only to recovery the production lost due to the accident but to increase the field production profile which remained almost constant while replacing the PLEM despite sealine were going to be disconnected. Moreover the field operability has been improved thanks to replacement methodology adopted.

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