Patent attributes
An open tip downhole expansion tool including a frustoconical member having a base at a diametrically smaller portion of the frustoconical member and a tip at a diametrically larger portion of the frustoconical member, the member having a radially outer zone and a radially inner zone and having an axial length extending from the base to the tip; an outer void in a material of the member along a length of the radially outer zone; and an inner void in a material of the member along a length of the radially inner zone, the outer and inner voids being located at different positions along the axial length of the frustoconical member, the outer and inner voids each causing the frustoconical member to present a first resistance to deformation when the voids are open and a higher resistance to deformation of the frustoconical member when the voids are collapsed.