Patent ID: 7610971

Claim:
A sidetracking system including a pair of axially connected mills located along a longitudinal axis, each mill having a plurality of tapered circumferentially disposed radially extending blades each having a tapered portion, at least some of the blades having a cutting surface thereon for cutting a window in a casing and then sidetracking in a formation, and a whipstock having at least three axially spaced ramps thereon, each ramp interspaced by a substantially axially extending portion, each said ramp being substantially the same angle of inclination to the longitudinal axis and also having the same angle of inclination as the taper on said tapered portion of the blades, the distance between the ramps being substantially the same as the distance between the tapered portions on the blades of the serially connected pair of mills, wherein the ramps support both mills before the mills cut the casing in which said system is located.