Tullow Wren Field Southern North Sea

The Wren exploration Wellhead No 53/03c-6 was recently surveyed with initial cleaning of marine growth (May 2015) and was found to have gas leak/ bubbles permeating from the 9-5/8” casing area. 

The casing was dredged to approximately 1m below the 9-5/8” casing hanger to verify the source of the gas bubbles.
A datum was established at North with the area of anomalies reported in the 1 - 2 o’clock and 7 o’clock positions. 

Further inspection and cleaning was carried out to establish:

  • A base line of the leak rate pre capping was carried out 
  • Establish the condition of the HP housing seal prep Confirm the gas leak path. 
  • Close Visual inspection of the AX gasket profile 
  • Visual inspection of internal sections of the conductor

A conductor cap was then installed using lift bags with inhibitor sticks installed prior to landing the cap and the leak rate re-tested.
Prior to departure from the Wren 53/03c- 13-5/8 conductor location an ROV ‘As Left Survey’ was undertaken. The conductor environmental cap was confirmed in position with gas bubbles emitting from the gas vent which was oriented in the vertical down position.  All diving operational equipment has been removed.

Project Well Internal Casing Inspection & Cap Installation
Customer Tullow/ COL
Location Wren 53/03c
Mode of Intervention Nitrox Diving (Surface Decompression)
Vessel Grand Canyon 2
Working Depth 40m