| 摘要 |
A method and a tool for use in commencing the drilling of a deviated well from a gap in the casing of a cased wellbore using a non-rotary drill string while maintaining the desired orientation of the drill bit by minimizing the effects of reactive torque and axial loading on the drill string. The tool comprises a drill bit, a downhole motor, a tubular member connected between the downhole motor and the drill string, and an anchor assembly slidably mounted on the tubular member which is actuated by the tubular member to engage the casing during drilling of the well. The tubular member includes a setting section for actuating the anchor assembly, a freewheel section to facilitate orientation of the drill bit prior to drilling, and a working section for maintaining the orientation of the drill bit during drilling. The method of drilling using the tool includes the steps of positioning the tool in the wellbore, actuating the anchor assembly to engage the casing, orienting the drill bit in the desired direction by rotating the drill string, and then drilling the well by applying weight on the drill string to advance the drill bit while maintaining the orientation of the drill bit. |
