Abstract: A system, method and apparatus for using a tool in a borehole is disclosed. The tool is disposed in the borehole. The tool includes a member rotatable substantially independently of the tool. The member is slidably coupled to a wall of the borehole. The tool is conveyed through the borehole to produce a rotation of the member as a result of the slidable coupling between the member and the wall of the borehole. A parameter of axial motion is determined from an angle of rotation of the member.

Abstract: A method for defining a permissible borehole curvature includes determining curvature characteristics of at least one of a borehole and a downhole assembly in the borehole and calculating an envelope of permissible borehole curvatures from a predetermined location in the borehole based on the curvature characteristics, a direction of the borehole at the predetermined location in the borehole, and a turning angle of the borehole relative to the direction of the borehole at the predetermined location.

Abstract: A drilling assembly supports a liner for making a wellbore. The BHA comprises a pilot bit and a reamer above it that is larger in diameter than the suspended liner. If the BHA needs to be pulled out, the reamer is brought into contact with the liner and a latch mechanism between the two engages as another latch that had held the reamer bit to the BHA is released. The reamer bit stays with the liner as the BHA is pulled and later reinserted. On the way in the BHA latches to the reamer bit which then unlatches from the liner bottom. Preferably, splines and a shoulder on the BHA are used to drive the reamer bit as opposed to any power being transmitted through the latch between the BHA and the reamer bit. However, the latch mechanism between the BHA and the reamer bit could also provide torque and weight on bit for drilling operations. The process may be repeated.

Abstract: A drilling assembly supports a liner for making a wellbore. The BHA comprises a pilot bit and a reamer above it that is larger in diameter than the suspended liner. If the BHA needs to be pulled out, the reamer is brought into contact with the liner and a latch mechanism between the two engages as another latch that had held the reamer bit to the BHA is released. The reamer bit stays with the liner as the BHA is pulled and later reinserted. On the way in the BHA latches to the reamer bit which then unlatches from the liner bottom. Preferably, splines and a shoulder on the BHA are used to drive the reamer bit as opposed to any power being transmitted through the latch between the BHA and the reamer bit. However, the latch mechanism between the BHA and the reamer bit could also provide torque and weight on bit for drilling operations. The process may be repeated.