Adjustable drill string reamer

A wellbore assembly, comprising:

• a drill string configured to be disposed within a wellbore;
• a side cutter coupled to a wall of the drill string and disposed uphole of a drill bit of the drill string;
• and
• a retaining member coupled to the drill string and to the side cutter, the retaining member arranged to retain the side cutter in an extended position and prevent the side cutter from moving inwardly toward a housing configured to house at least part of the side cutter, the retaining member configured to break under a shear force applied by the side cutter bearing against a portion of the wellbore comprising a reduced diameter that biases, under a weight on bit applied in a downhole direction against the inner component, the side cutter inwardly until the side cutter breaks the retaining member to allow the side cutter to move to a retracted position in which the side cutter is at least partially housed within the housing, the side cutter defining, in the extend position, a first drilling diameter greater than a drilling diameter of the drill bit, and the side cutter defining, in the retracted position, a second drilling diameter less than the first drilling diameter and such that the drill string is able to drift through the portion of the wellbore comprising the reduced diameter.

A method, comprising:

• drilling, with a drill string disposed inside a wellbore comprising a casing and an open hole packer attached to the casing, a drillable wellbore component, the drill string comprising a drill bit and a reamer assembly residing uphole of the drill bit, the reamer assembly comprising i) a side cutter coupled to the drill string and ii) a retaining member coupled to the drill string and to the side cutter, the retaining member arranged to retain the side cutter in an extended position and prevent the side cutter from moving inwardly toward a housing configured to house at least part of the side cutter, the retaining member configured to break under a shear force applied by the side cutter bearing against a portion of the wellbore comprising a reduced diameter that biases, under a weight on bit applied in a downhole direction against the inner component, the side cutter inwardly until the side cutter breaks the retaining member to allow the side cutter to move to a retracted position in which the side cutter is at least partially housed within the housing, the side cutter defining, in the extend position, a first drilling diameter greater than a drilling diameter of the drill bit, and the side cutter defining, in the retracted position, a second drilling diameter less than the first drilling diameter and such that the drill string is able to drift pass the portion of the wellbore comprising the reduced diameter;
• applying weight on the drill string to push the side cutter against an inwardly projecting shoulder of the open hole packer until the retaining member breaks under a shear force applied by the side cutter bearing against the inwardly projecting shoulder of the open hole packer and the side cutter moves, with the retaining member broken, to the retracted position;
• and
• moving, with the side cutter in the retracted portion, the drill bit and side cutters through the casing past the open hole packer to continue to drill downhole of the open hole packer.