US Patent 11859457 Accessing lateral wellbores in a multilateral well

A wellbore whipstock tool assembly includes a body that includes an uphole axial surface that is slanted from one portion of an edge of the uphole axial surface to another portion of the edge of the uphole axial surface, a downhole axial surface opposite the uphole axial surface, and a radial surface between the uphole axial surface and the downhole axial surface; one or more keys formed on the radial surface and configured to secure into one or more keyholes formed in a casing of a wellbore; and a bore that extends between an opening in the uphole axial surface and an opening in the downhole axial surface, the bore sized to receive a bottom hole assembly of an intervention tool.