Stage collar

Cementing & Well Integrity

A stage collar is a cementing valve installed in the casing string that allows the cement job to be performed in multiple stages. It is used when the hydrostatic pressure of a single long column of cement would exceed the formation fracture gradient, breaking down the rock.

The first stage is pumped through the shoe as normal. Then, a bomb is dropped to open the stage collar ports higher up the string, allowing the second stage to be circulated and cemented above the collar. Finally, a closing plug seals the ports permanently.