Dual Stage Cementing Collar
Asta Dual Stage Cementing Collar (DSCC) is designed in mechanical system to apply the opening and closing sleeve. DSCC is used for two stage cementation of well, to reduce the circulating pressure, cement contamination and quantity cement required. The Asta DSCC is available in variant size, type of thread connection and grade material according to API 5CT. The DSCC equipment consisting of Baffle Plate, First Stage/Flexible Plug, Free Fall/Opening Device and Closing Plug made from special material which are PDC drillable.
Pin and Box threads are identical to the casing threads. Stage collar integral connection is designed for gas tightness. Seals on opening sleeve provide internal and external pressure integrity across the fluid ports.
Opening device has landed and, after pressure is applied, the lower set of shear mechanisms is broken and the sleeve shifts downward to uncover the fluid ports. Pumping operations can now be conducted through the stage collar.
The closing plug has landed and, after pressure is applied, the upper set of shear mechanisms is broken and the sleeve shifts downward, shutting off the fluid ports. Double seals above and below the ports provide pressure integrity.
- ASTA float shoe and float collar along with the ASTA Dual Stage Cementing Collar, are installed in the casing string and the casing is run to bottom.
- The baffle plate is installed into the land on the ASTA float collar.
- Circulation is established and first-stage cement is mixed and pumped.
- The first-stage sealing plug is launched and cement is displaced. At the conclusion of displacement, the Flexible Plug lands and affects a seal against the ASTA Float Collar.
- The free-fall opening device is dropped and allowed to gravitate to position. Pressure is applied to the casing and the stage collar is opened.
- Circulation is established and second-stage cement is mixed and pumped.
- The Top/Closing plug is launched and cement is displaced. At the conclusion of displacement, the closing plug lands and affects a seal in the stage collar. Pressure is applied to the casing and the stage collar is closed.