The WT-Master Plus Wellbore Departure Systems represents an application specific and results-driven approach to one-trip reliability and cost optimization. The running assembly consists of a mill and whipstock assembly. The anchor sub-assembly can be a retrievable hydraulic anchor, a mechanical anchor, a permanent packer, and an open hole inflatable anchor or expandable hydraulic anchor. Cased-hole anchors, except the permanent packer and Thru-Tubing Anchor, are designed for dependable retrieval. The objective of the WT-Master Plus Wellbore Departure systems is to accomplish the following steps in a single trip:
•Run the whipstock and a milling assembly
•Orient the whipstock assembly with Measuring While Drilling (MWD) toolor Gyroscope
•Set the anchor
•Release the mill from the whip
•Mill the window
•Drill the rathole or lateral
•Pull out of the hole
The result is a full-size usable window achieved within a minimum of milling time with safe and easy passage for the required drilling assembly.
The whipstock assembly may be oriented and set at any depth. It should be located immediately above a casing collar to provide a smooth I.D. in which to set the anchor and mill the window. A surveying system should be run with the WT-Master Plus Wellbore Departure Systems to determine the preferred orientation for the sidetrack. When orientating in a specific direction and if a hole angle of more than two degrees exits at the setting depth, then it is recommended that the whipstock assembly is set 0 – 90 degrees to the right or left of high side of the hole. With small modifications, the WT-Master Plus Wellbore Departure Systems can be configured to exit from the low side of the hole. After setting the anchor, either hydraulically or mechanically, a load is applied to the drill string to shear the break bolt between the Mill and whip. At this point, string rotation may begin for milling of the window, followed by drilling of the rat-hole.