Cost effective shallow water subsea intervention on lift boat with cantilever deck

In Brief
Lift boat equipped with cantilever deck facilitates cost effective shallow water subsea intervention
Well Abandonment
Product Line
Well Intervention
Europe CIS
  • Taqa required support for a subsea well intervention campaign in the Dutch sector of the Southern North Sea to: establish if sustainable production from the well could be reinstated and if not, prepare the well for a future abandonment programme; conduct a variety of interventions ranging from wireline fishing, to water shut off, re-perforating, and well testing
  • In line with Taqa’s existing contracting framework, Expro were appointed lead contractor to both modify the vessel ready for subsea well intervention and manage a well services alliance comprising Expro, BJ Services and BakerHughes
  • Taqa identified that a self-propelled lift boat could be modified to perform shallow water subsea well intervention, however the vessel selected for this campaign was not equipped with a moon pool, and required a cantilever for this operation
Expro Excellence
  • Key to achieving well re-entry was the fabrication of a cantilever deck that could be skidded over the top of the subsea well to form the work platform for intervention equipment
  • A cantilever deck was designed and manufactured by Expro – a primary feature was its ability to index through nine positions to centre itself over the well
  • Over a 14 day period, project-specific rig vessel modifications were undertaken to pre-install well service equipment, comprising surface well testing, coil tubing, e-line and slickline packages, this also included the installation of flare booms on the port and starboard sides of the vessel
  • Once on location a riser was installed and the well intervention began with well inspections using Expro’s slickline services to establish if the wells were clean of debris from surface to the reservoir – the slickline was used to recover the fish and mechanical plugs previously installed in the well
  • Wireline was used extensively throughout the project using Expro’s combined e-line and slickline units to minimise number of coiled tubing operations
  • The first well required milling to clear blockages in the tubing and a cement plug to be set on top of a mechanical bridge plug
  • The programme also called for production logging and then additional perforating
  • In order to clear a restriction in the well, the tail pipe was cut off using an Expro radial cutting torch
Value to client
  • Improvement in productivity following the successful intervention of three wells
  • Significant savings – avoided the need for a jack-up rig or intervention vessel
  • Single project manager on multi interface project – high operational efficiency
  • Fast track delivery using vessel of opportunity with custom modifications

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