NWS Wet Shoe Sub

Provides a positive indication of cement displacement and can eliminate the need for a costly perforating run


The NWS wet shoe sub is designed to provide a positive indication of cement displacement, and the ability to have a wet shoe for first-zone injection eliminates the need for a costly perforating run. The wiper plug is pumped down the casing behind the cement to the seat in the wet shoe sub. A pressure increase indicates the plug is on seat; continued increase in pressure shears the plug seat, which moves it down to allow circulation around the wiper plug, creating a ‘wet shoe’ for first zone injection.


  • Large flow area around the wiper plug after shear-out
  • Positive indication wiper plug is on seat
  • Circulation through tool after plug seat shear-out
  • No explosives required on location
  • Exchangeable wiper plug seat insert to accommodate cemented frac sleeve dart system


  • Time and cost efficiency compared with traditional TCP operations
  • Ability to employ continuous pumping operations
  • Reduces HSE risk by eliminating need for dedicated coiled tubing operations
  • Decreases amount of water used compared to traditional toe initiation


  • Fracturing/stimulation
  • Production
  • Injection
  • NWS Wet Shoe Sub Technical Summary

  • Refrac Liner Bakken Case Study