Abstract: In a drill pipe handling apparatus, a pipe gripping mechanism comprises three pipe-gripping jaws arranged to grip a pipe at locations adjacent the apices of a triangle containing the axis of the pipe. A first pipe gripping jaw is connectible to a first pivoted arm at any selected one of a set of plural distances from the pivot axis of the first arm and connected to the first arm at one of those plural distances, and a second jaw is connectible to the second arm at any selected one of the same set of plural distances from the pivot axis of the second arm and connected to the second arm at the same one of those plural distances at which the first jaw is connected to the first arm. Because the same first and second jaws are connectible to the arms at plural distances from the pivot axes, the same jaws can accommodate a wide range of pipe diameters.

Abstract: In a drill pipe handling apparatus, a pipe gripping mechanism comprises three pipe-gripping jaws arranged to grip a pipe at locations adjacent the apices of a triangle containing the axis of the pipe. A first pipe gripping jaw is connectible to a first pivoted arm at any selected one of plural distances from the pivot axis of the first arm and connected to the first arm at one of those plural distances, and a second jaw is connectible to the second arm at any selected one of said plural distances from the pivot axis of the second arm and connected to said second arm at said one of said plural distances. Because the same first and second jaws are connectible to the arms at plural distances from the pivot axes, the same jaws can accommodate a wide range of pipe diameters.

Abstract: Well drilling and well casing placement are carried out by a process in which a drill string and surrounding casing are advanced while being rotated, preferably in opposite directions. The process is preferably carried out using a drill rig having a mast that is movable along its direction of elongation and a casing rotation table fixed to the mast.