Shallow-Angle Quickcut™ System with Multicatch™ Anchor
Enables Sidetracking Expandable Liner to Save 14 Days in Ultra-Deepwater
Sidetrack from a 13 3/8-in. expandable liner and allow a 13 1/2-in. drilling bottomhole assembly (BHA) and 12 1/4-in. casing to pass the whipstock without issue.
Avoid collapsing the expandable liner during the sidetrack operation by limiting flow rates and pressures well below the norm, yet still finishing the milling operation and recovering cuttings.
Maintain a low dogleg and smoothly transition from the main bore to the sidetrack while minimizing the risks associated with thin-wall liners and channeled cement.
When other vendors could not provide a timely solution to exit the expandable liner, Shell contacted Weatherford for off-the-shelf options.
Together, Shell and Weatherford determined the solution—including the shallow-angle QuickCut system with MultiCatch anchor and 12 1/4-in. OD milling BHA—to install a window in the 13.77-in. solid expandable ID. The companies also identified the need for two additional milling BHAs to open the window to a full 13 1/2-in. OD for drilling and completing the well as planned.
Weatherford mobilized supervisors and the first-run modified BHA to the deepwater rig within 3 days. Additional BHAs and a contingency mill arrived within the following 2 days. A total of 16 mills, nine of which had custom ODs, were dressed, inspected, and dispatched in this timeframe.
On the initial run, the BHA with hydraulic-set system enabled cutting a 27 1/2-ft (8.4-m) window and reaming a 45-ft (13.8-m) rathole in 22 hours. The system achieved success despite the limited flow to avoid liner collapse and the thin-wall liner with channeled cement on the backside.
The second BHA consisted of three mills, from a 12 1/2-in. OD, to a 12 3/4-in. OD, and a 13-in. OD. Keeping the torque and weight low during this run helped to avoid twisting off and losing the lower hole section. Milling and reaming on this run lasted 6 hours.
The final BHA included two full-drift 13 1/2-in. OD mills with a 13 1/4-in. OD mill on bottom to fully open the window for future drilling and completion BHAs. This run lasted a total of 29 hours to complete the operation and polish the window.
After the sidetracking operation, a 13 1/2-in. motor, 13 1/2-in. rotary steerable assembly, and 12 1/4-in. were run through the window to finish this contingency hole section.
Value to Customer
The Weatherford solution saved Shell 14 days, valued at US $14 million dollars, compared to the other option of sidetracking the 16-in. casing and predrilling an entire hole section.