Flow Lock Subs

Allows circulation through the completion string until setting of hydraulic equipment above it is required in openhole multistage completions


After a ball is dropped from surface and circulated down to the Flow Lock Sub™, an increase in the system pressure will shift the internal components of the Flow Lock Sub and shut in the circulating bypass ports. Hydraulic equipment above may be set, and pressure integrity is maintained above and below, even if the ball rolls off the seat.

Our Flow Lock Sub XP version features extended pockets for dual-ball operations where liner hangers require dual-ball setting mechanisms.

SPE papers:


  • Ball-activated sleeve seals off the casing inside diameter from the annulus
  • Once sealed, the Flow Lock Sub seals from above and below the sub
  • Compatible with a range of ball outside diameters
  • Field-adjustable activation pressure
  • Locked open when running and circulating
  • After closing, locked in closed position
  • Allows high-pressure casing test after closing - up to 15,000 psi
  • Extended pocket for dual-ball operations
  • No E-line or coiled tubing intervention needed to close


  • Once the flow path is closed, it is locked close, even without the activation ball in place
  • Provides a reliable method to set pressure-activated components in the wellbore
  • Circulation through tool to condition wellbore before closing
  • Single closing ball pumped to seat to close and lock sub
  • Casing integrity test permissible after closing
  • Debris tolerant during activation
  • Used for liner with dual-ball setting mechanism


  • Open-hole completions that require setting of pressure-activated tools such as packers and liner hangers
  • Flow Lock Sub Data Sheet

  • Flow Lock Sub XP Data Sheet

  • Expedited Contingency LHS Saves Operator Potential Downtime Case Study

  • 15-Stage, 75 i-Frac Sleeve Completion Case Study

  • First NOV Voyager 15XT OH Packer Deployed in a Tight HPHT Reservoir Case Study

  • URFC Allows Operator to Casing Deploy Cemented and Openhole Liners Case Study

  • Oilfield Technology Feature: Unlocking Tight HPHT Reservoirs Economically

  • Lower Completions Portfolio

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