SPIRAL WHIPSTOCK FOR LOW-SIDE CASING EXITS

摘要

A whipstock features a spiral ramp so that, in a horizontal run, access to a milled window with other tools is not impeded because such tools can traverse onto the ramp and still be directed to the window. Angular rotation of the ramp can be at 180° or more and the pitch is selected to avoid getting the equipment being advanced into a bind. Optionally, a guide track can be configured into the whipstock ramp to help the mill follow the spiral path until the proper orientation is obtained and the track ends to allow separation of the mill from the track. A slot can be provided near the ramp upper end to aid in retrieval operations.