Patent ID: 8210279

Claim:
A method of tripping pipe on a rig floor that is positioned over a well wherein a drill string extends out of the well, the drill string comprising a series of connected drill pipes, wherein an uppermost drill pipe in the series has an upper end that extends above the rig floor by a stick-up height, the method comprising the steps of: measuring, with a measuring device operatively connected to and operatively controlled by a controller, a length characteristic of a first drill pipe that is separated from and out of alignment with the drill string; receiving, at the controller, the length characteristic; calculating, with the controller and based upon at least the length characteristic of the first drill pipe and the stick-up height, a first vertical position into which to position the first drill pipe upwardly and into vertical alignment with the drill string to achieve a predetermined clearance distance between the lower end of the first drill pipe and the upper end of the uppermost drill pipe in the drill string; controlling machinery with the controller to position the first drill pipe upwardly above and into vertical alignment with the drill string to the first vertical position; connecting the first drill pipe to the uppermost drill pipe in the drill string; and positioning the drill string into the well.