Patent classifications
G05B2219/1185
WELL CONSTRUCTION DISPLAY
A method for steering a downhole tool in a wellbore includes measuring a tool face when the drill bit is off-bottom, measuring an angular position of a drill string when the drill bit is off-bottom, and measuring a torque on the drill string when the drill bit is off-bottom. The method also includes measuring the tool face when the drill bit is on-bottom and measuring the torque on the drill string when the drill bit is on-bottom. The method also includes determining a transfer function comprising the angular position of the quill, the difference between the tool face when the drill bit is on-bottom and off-bottom, and the difference between the torque when the drill bit is on-bottom and off-bottom. The angular position of the drill string is varied at the surface, based upon the transfer function, to reduce an angle between the tool face when the drill bit is on-bottom and a target tool face.