Junction Stability and Sand Exclusion
Conventional multilateral junctions often involve precut casing windows, mill-over liner tops or complex mechanical anchors. Each of these techniques, however, has limitations. Precut windows reduce casing integrity; mill-over liner tops can collapse into the main wellbore; and conventional liner hangers restrict wellbore access.

Milling Casing Windows

In contrast, RapidExclude and RapidConnect multilateral systems create a structural connection between liners and the primary casing. Both systems use a RapidAccess indexing casing coupling (ICC) installed in the main casing to orient commercially available retrievable whipstocks and mill directional casing-exit “windows.”  

This fullbore device maintains casing integrity until an exit window is cut and allows conventional cementing operations. The ICC also provides a permanent platform for selective lateral access and remedial operations.

Junction Connectivity

Conventional junctions resist collapse loads of 10 to 100 psi [0.07 to 0.7 MPa] and have open gaps of more than 1 in. [2.5 cm]. The collapse strength of RapidExclude junctions equals 2500 psi [17 MPa] while excluding particles as small as 40 microns. RapidConnect collapse strength is about 1500 psi [10 MPa].

Available for 7-in. and 9 5⁄8-in. casing, these two systems provide stability in unstable or high-stress formations. These high-strength junctions are used in unstable, layered, faulted and compartmentalized reservoir applications. The RapidSeal multilateral system is designed for wells that require junction pressure integrity. [note 2]

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