The multilateral system creates a cemented junction with full liner access to the lateral bore. (Image courtesy of Weatherford)

As the world’s first one-trip Level 4 multilateral system, the OneTrip StarBurst saves operators significant time and money.

Weatherford recently installed the multilateral system in the Norwegian North Sea for StatoilHydro, doing so in a single trip, despite heaving seas. The junction was installed at 13,300 ft (4,054 m) and the casing exit was milled in 9 5/8-in., 53.5-lb/ft, 13% Super Chrome 110, and the rathole milled in Garn 4 hard impermeable sandstone with quartz stringers.

This was the first one-trip TAML level 4 multilateral system ever run, and the first to mill through such challenging casing material with a very hard formation on the outside. The result — it only took 5 1/2 hours to mill a 19.7-ft (6-m) window and 19.7-ft (6-m) rathole, saving the operator at least 2/3 the time of other existing technologies — a significant savings, given that this work often takes place in expensive offshore environments.

The system incorporates the proven QuickCut milling system for orientation of the whipstock-anchor assembly, milling of the window, and drilling of the rathole in a single run.

The system may be used for new development drilling and re-entries and provides operators with a simple, low-risk Level 4 multilateral solution. Its one-trip capability reduces costs and eliminates expensive hardware. The system is particularly well suited for wells in mature fields, where production rates are declining. Nearby additional reserves can be economically accessed with laterals while original wellbore production is maintained. The system is compatible with conventional or intelligent completions.

This single-trip multilateral system creates a cemented junction with full liner access to the lateral bore. This system is a low-risk method of obtaining new reserves while maintaining production from the existing well bore. It incorporates the industry-proven QuickCut milling system for orientation of the whipstock-packer assembly, milling the window, and drilling the rathole in a single run. The unique, multipurpose hollow whipstock is used in the milling, drilling and completion phases. The whipstock is designed to remain in the well bore to eliminate recovery risks. The unique lug-and-rail technology protects the whipstock pressure plate during cut-out and accurately directs the mill into the casing wall. After the window is milled and the lateral is drilled, a conventional lateral liner assembly is run into the lateral, cemented, and anchored back to the mainbore above the window. Overlapping concentric strings, combined with the cement, ensure a TAML level 4 junction, with maximum support and formation isolation.

The liner and whipstock pressure plate is then perforated using a low-side-oriented technique which reopens the mainbore. The completion of the multilateral well can be done with either intelligent or standard completion methods. Production can also be commingled or perforating can simply be deferred to retain isolation of the new lateral.

This multilateral system is available in 9 5/8-in., 40 to 53.5 lb/ft sizes. The packer has been tested to ISO 14310 V3 requirements. The pressure rating is 5,000 psi from below the packer and 3,500 psi from above the packer at 275°F (135°C). A high pressure/high temperature, i.e., 5,000 psi at 302°F (150°C) model is available.