Drilling, and especially directional drilling, employs a number of tools for determining the position of a drill bit and for directing the drilling force of the drill bit. These tools often reside within the drill string, near the drill bit, and either near or within a drill collar or near or within a sub in the bottom hole assembly. The tools require a secure fit within the drill string in order to ensure their stable operation. Blades or fins can be affixed to the exterior of such tools to centralize and stabilize these tools within the drill pipe of the drill string. In particular, fins made of materials, including rubber, hard plastics, other pliable or shearable materials, or combinations thereof, can be affixed to the tools to dampen the shock and vibrations common near the bottom assembly.
When these downhole tools stop functioning correctly, or when the drill string becomes stuck in the wellbore, the downhole tools must be retrieved and, frequently, are wire-lined out of the drill string and to the surface. During this retrieval of the downhole tools, the fins affixed to the tools, which assist in the operation and stability of the tools, can become obstacles in removing the tools from the drill string due to the need to pass these downhole tools with fins through restrictions in the drill string in order to retrieve the tools to the surface. Generally, the fins on the tools tend to extend towards an outer diameter of the drill string that is greater than that which could pass through various restrictions in the interior of the drill string.
Therefore, a need exists for a shearing apparatus that can reside in a drill string, or on the tool itself, for the purpose of shearing, trimming, and/or reducing objects, including materials such as fins on the body of the objects, with great stability and accuracy to allow the objects, such as downhole tools, to pass through restrictions in the drill string and, thus, be retrieved to the surface.
In addition, a need exists for methods of using a shearing apparatus to shear, trim, and/or reduce objects in a drill string, including materials such as fins on the body of the objects, with great stability and accuracy to allow the objects to pass through restrictions in the drill string and, thus, be retrieved to the surface. The apparatus and methods include securely fitting the downhole retrievable tools, including measuring-while-drilling tools, with fins and then shearing, trimming, and/or reducing the fins to retrieve the same tool through relatively small drill string restrictions and to the surface.
Further, a need exists for an apparatus and methods capable of shearing, trimming, and/or reducing multiple retrievable tools, as these downhole tools are removed from a drill string and retrieved to the surface.
The present embodiments meet these needs.