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Welltec is a key enabler of the technology required to boost subsea recovery


With a constantly growing number of subsea installations there is a similar requirement for interventions. Examples from certain areas show that there exists a gap of 30-40% in recovery from subsea fields compared to similar platform based fields, where the discrepancy to a large degree can be contributed to lack of regular downhole production maintenance, basically lack of interventions, Welltec® is a key enabler of the technology required to boost subsea recovery.
    RLWI interventions.
    Deep water.


Traditionally, semi-submersibles have been used to perform interventions on subsea wells using a riser based system. However this method can be time consuming, expensive and requiring long lead times for both rig and riser system. Almost two decades ago a true breakthrough came with the courage to run e-line through open water to intervene in a subsea well, also referred to as Riserless Light Well Intervention – RLWI.

Capitalizing on existing, more readily available equipment to accomplish interventions, RLWI can be accomplished with purpose built vessels or a vessel of opportunity. No rig nor riser is required.

By far most interventions can be performed by wireline with applications covering from conventional e-line conveyed logging, perforation etc. to mechanical manipulation, obstruction removal to spotting chemicals or other fluids. Riser conveyed intervention is only required for complete workover where tubing is retrieved and/or where the application is to pump major amounts of fluid.


  • Inherently safer
  • Less equipment, fewer people
  • No need for a rig
  • E-line operations
  • Flexible
  • Universal
  • Reliable
  • Fewer lifts, clear roles and responsibilities
  • Reduced footprint, higher sustainability
  • Required vessels are available
  • Fast, efficient
  • Can work in any water depth
  • Global experience and suppliers
  • Proven track record of successes

Case highlight


An operator planned to set a lock open sleeve across a failed SSSV on a subsea well. The well had not been re-entered since it began production thus downhole conditions...

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  • Scale and metal milling
  • Sand/debris clean out
  • Crown plug pulling
  • Nipple profile milling
  • Fishing with DH snubbing unit
  • Perforating / re-perforation
  • Zone isolation (plug/straddle)
  • Camera runs
  • Scale treatment placement
  • Cutting tubulars
  • Change-out of gas lift valves
  • Shifting sliding sleeves and valves
  • Production enhancement services
  • Downhole snubbing capability
  • Swaging of deformed tubing/pipe
  • Installing and pulling plugs, straddles and patches
  • Data gathering (PLT, CBL, PNL)
  • Inspection/repair/installation of insert DHSV
  • Milling of short scale bridges
  • Selective tracer injection or sampling


Tools applied