The Hydraulic Stage Collar is used to effectively cement an upper section of the casing string above an External Casing Packer (ECP) assembly. In some cases, lead slurry is circulated around the lower section of the casing string. For other applications, slotted liners or bare-foot completions make cementing below the ECP unnecessary, or undesirable.
The stage collar is hydraulic opening. Circulating ports are opened by continuing to apply internal casing pressure after the ECP is set. Normally, pressure required for opening the circulating ports is adjusted to about 500 PSI (3.5 MPa) greater than the ECP operating pressure. Circulating ports are closed by the cement displacement plug. The port closing sleeve is positively locked in position after cementing. Internal parts are easily drilled to provide a full opening bore through the port collar assembly.
FEATURES & BENEFITS
Hydraulic Stage Collar may be used in vertical, deviated or horizontal wells. No free-fall plugs are required to operate the system.
The tool body is manufactured from alloy grade steel that is able to resist high bending forces in the well radius.
When run above an ECP assembly, system is very effective for blocking gas migration through cement, and for minimizing cement losses to thief zones.
Hydraulic Stage Collars are manufactured with the same thread specifications as customer installed casing strings.
A latch ring positively locks closing sleeve in closed position.
Full opening bore is provided after drillout
Locking plugs allow for quick drillout
OPERATING PROCEDURE
While running the casing string in the hole and during the cementing of the first stage, the stage collar remains in the closed position. The first-stage flexible plug passes through the stage collar without actuating the sleeves. To open the stage collar cementing ports, pressure is applied in the casing to shear the opening sleeve shear screws and to move the sleeve down to expose cementing ports.
Second-stage cement is then pumped and displaced with the closing plug. The closing plug lands on the closing sleeve seat and pressure is applied to shear the closing sleeve shear pins and force the sleeve down to close the cementing ports. The closing sleeve is permanently latched in the closed position.
INTRODUCTION
