METHOD AND APPARATUS FOR DRILLING WITH A FLEXIBLE SHAFT WHILE USING HYDRAULIC ASSISTANCE

摘要

An apparatus and method are disclosed for applying thrust (weight on bit) to a drill bit when drilling with a flexible drilling shaft while creating perforations in a cased well. The thrust is applied directly to the drill bit instead of applying it to the drill bit through the flexible drilling shaft. A support bracket is also in contact with a piston and is in slidable contact with the tool housing. A portion of the piston is positioned inside a chamber in the housing and is slidably attached to the chamber walls. As hydraulic fluid flows into the chamber opposite the piston, the piston is forced toward the drill bit. As the piston moves toward the drill bit, force is exerted on the support bracket whichcauses the bracket to move toward the drill bit. This force is transferred to the drill bit during the drilling process, thereby supplying the force (weight on bit) needed by the drill bit to effectively drill through a desired material.