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Lesson Learnt From A Sub-Sea Well Intervention. Lessons Learnt From A North Sea Sub-Sea Well Intervention. Background. 2010 Following a plant shut down the sub-sea well would not restart. Surface tests indicated it was either a failure of a TR-SC-SSSV or the Matrix.
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Lessons Learnt From A North Sea Sub-Sea Well Intervention Background. • 2010 Following a plant shut down the sub-sea well would not restart. • Surface tests indicated it was either a failure of a TR-SC-SSSV or the Matrix. • 2011 Sub-Sea Intervention planned with a Light Well Intervention Vessel (LWIV). • The plan was to investigate why the well would not flow. • The well had been drilled by a 3rd party turnkey operation 10 years previously. • No well interventions had been carried out during the interim period. • The well was completed with a sub-sea horizontal tree.
Lessons Learnt From A North Sea Sub-Sea Well Intervention • Learning. • For older sub-sea wells use a resilient AX seal for wellhead to LWIV interface.
Lessons Learnt From A North Sea Sub-Sea Well Intervention Be prepared for the unexpected.
Lessons Learnt From A North Sea Sub-Sea Well Intervention • Unable to pull 2nd Crown Plug. • Normal slickline bailers made no head way. • A Welltec brush had been mobilised to clean the TR-SC-SSSV. • A Weltec Vacuum tool had also been mobilised.
Lessons Learnt From A North Sea Sub-Sea Well Intervention • Rope and propant were recovered from the top of the 2nd Crown Plug. • Drilling Well Reports stated the Crown Plugs had been set on drill pipe.
Lessons Learnt From A North Sea Sub-Sea Well Intervention • Take a Camera. • An Expro camera had been mobilised to check the operability of the TR-SC-SSSV. • Camera had side view option and found a 360 degree tubing indent anomaly. • Photo 1 shows top of flapper in TR-SC-SSSV. • Photo 2 shows debris at top of TR-SC-SSSV internal flapper sleeve. • Photo 3 shows indent anomaly in tubing above TR-SC-SSSV.