Patent ID: 6050334
Filing Date: 2000-04-18
Classification: E21B

Abstract:
A single trip whipstock assembly for forming a window in the casing of a wellbore, said casing defining an inner facing surface which defines the interior dimensions thereof and an outer facing surface defining the exterior dimensions thereof, the whipstock assembly comprising:a whipstock having a milling tool attached to the upper end thereof and a packer or anchor attached to the lower end thereof, the milling tool having a diameter and the packer or anchor being settable to fix the depth of the whipstock prior to, but during the same trip as, operation of the milling tool to form the window in the casing of the wellbore, the upper end of the whipstock being formed with a ramp surface which extends at an angle to An axis of the wellbore greater than the angle of a main deflecting surface of the whipstock to the axis of the wellbore, wherein, when in use, the ramp surface meets the main deflecting surface at a point radially spaced from the inner facing surface of the wellbore casing by a distance less than the diameter of the milling tool.