Conductor pipe joints installed on land rigs, are usually connected by welding bevelled prepared ends of the pipes together. This is a time consuming operation that requires an average of three hours per joint.
On a Jack-up, to reduce the time of the operations and when it is practicable, driveable threaded quick connectors (i.e. the RL-4) and driveable squnch joint connectors such as the Fast Realising Joint (i.e. the ALT-2), should be used.
a) A Squnch Joint (Refer to figure 4.c) is a threadless automatic mechanical lock/release connection that makes up without rotation. The extremely strong weight-set connection is well suited for connecting large diameter conductor joints, and connecting the casing to the wellhead housing extension.
The type ALT-2 (Refer to table 4.d) heavy-duty squnch joint is used for pipe joins generally up to 36" OD, but larger sizes are available. It is easily stabbed, driveable, reusable and can be released mechanically.
It is suitable for the severest conditions above the mud line and can be used below the mud line when the conductor is driven into place. The 20" ALT-2 is an ideal high-pressure housing extension connector, with an internal pressure rating of up to 5,000psi.
The type ST-2 standard duty squnch joint (Refer to table 4.d) is not a driveable connector. It is used to connect pipe joints up to 30" OD, and is run into a pre-drilled hole and cemented in place. It is recommended for use above the mud line and is reusable and mechanically released.
b) The Quick Thread Connection RL-4 (Refer to Table) is a very rigid connection for conductor and casing connections and requires just one-quarter turn for full make up. The helix angle of the patented, interlocking thread form, in combination with other connector geometries creates a preload force between the pin and box. The 30" and larger RL-4 conductor connectors have a generous shoulder for efficient driving.
Four identical threads 90° apart make-up simultaneously. The thread interface is tapered at 4" per ft of diameter. The connector box has four slots cut on the OD, close to the shoulder of the box and the connector pin has four recessed grooves cut on its OD adjacent to the slots on the box.
To activate the anti-rotation tab, a 90° incision is made with the impact tool into the anti-rotation slot. A strip of metal is bent into the recessed groove in the pin which provides a positive mechanical lock.
It does not need power tongs for make-up and is releasable and reusable. It has a high 9° stab angle with dual stab guides. A negative 5° backrake thread interlock reduces belling tendency. The standard specifications for some selected pin and box sets are shown in table 4.d.
ENI S.p.A. Agip Division
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