Stage Cementing Equipment

Casing-mounted subs with closable ports that permit cement to be circulated into the annulus at an intermediate point in the string, enabling two-stage or multi-stage placement. The diverter valve (DV) is the historic source of the common DV tool name.

Stage collars whose ports are opened by applied tubing pressure acting on an internal piston rather than by a dropped opening bomb, used where dropping a bomb is impractical or where positive pressure actuation is preferred.

Stage collars actuated by mechanical means, typically a free-falling opening bomb that lands on a sliding opening sleeve to expose the ports, then a closing plug that shifts a closing sleeve to seal them after the second-stage slurry is placed.

Wiper plugs pumped ahead of and behind the cement slurry to separate it from drilling and displacement fluids and to wipe the casing inner wall; bottom plugs rupture on a landing seat while top plugs provide a positive bump indication.

Surface manifold equipment installed atop the casing that holds the cementing plugs and opening/closing bombs for release at the correct point in the job and routes slurry from the pumping unit into the string.

Flexible or rigid annular devices run on the casing below a stage collar that support the cement column and reduce slurry fallback into formations below, limiting hydrostatic loading on weak zones during staged placement.

Set-in-place packoff tools used in remedial and squeeze cementing; a cement retainer provides a one-way valve to inject cement below it, while a bridge plug isolates the wellbore by forming a solid barrier at a set depth.

Bow-spring or rigid collars fitted on the casing to keep it concentric in the hole, promoting a uniform annular cement sheath and improving mud removal and zonal isolation during the cement job.