Patent ID: 8469096
Filing Date: 2013-06-25
Classification: E21B

Abstract:
1. A whipstock having a longitudinal axis and comprising: a tapered face surface, at least a part of which is continuously inclined with respect to the longitudinal axis, for guiding a milling head as the milling head passes from a top end to a bottom end of the inclined part of the face surface; and a deflection arrangement located between the top end and bottom end of the inclined part of the face surface and protruding from the inclined part of the face surface and having first and second deflection surfaces, at least a part of each of the deflection surfaces being raised above the inclined part of the face surface and each of the first and second deflection surfaces being acutely inclined relative to the face surface inclined at a greater angle with respect to the longitudinal axis than the inclined part of the face surface in the location of the deflection arrangement, wherein the first deflection surface is located closer to the top end of the inclined part of the face surface than the second deflection surface; and wherein a milling head passing along the whipstock tapered face surface will be deflected away from the inclined part of the face surface by the first and second deflection surfaces and return to the inclined part of the face surface after moving past the deflection arrangement.