Abstract: The roots of the box threads in a drill collar or heavyweight drill pipe are configured to reduce the connection stresses encountered during drilling and makeup of the connection. The thread root design in the box reduces fatigue damage caused by makeup torque and cyclic stressing of the engaged drill string connection as it is rotated around curved sections of the well bore. A conventional V-type thread form in the box is provided with an enlarged root radius having its center point offset from the centerline of the opposing thread flanks. The load flank of the thread tangentially engages the arc of the root. The stab flank of the thread is intersected by the enlarged root radius extending to a flat intersecting surface that may extend as far up as the thread pitch diameter.

Abstract: An apparatus and method are provided for enhancing fatigue and load properties of subterranean well drill pipe immediate the area of securement of pipe sections by providing a weld in a discontinuous plane to secure pipe sections to each other, said weld having a greater cross section of welded surface and ability to distribute stresses which is less prone to fail due to rotational, tensile, and bending stresses, mid due to heavy loads and stresses arising from shock loading.

Abstract: An apparatus and method are provided for enhancing fatigue and stress resistance properties of a subterranean well drill pipe string section by providing a helical groove near the pipe to tool joint weld. Stresses in and around the top portion of the pipe are redistributed to and absorbed by the helical groove region of the drill pipe string section, which has a relatively greater resistance to fatigue caused by bending and other stresses, thereby making the drill pipe string section less prone to fail due to rotational, tensile, and bending stresses.

Abstract: An apparatus and method are provided for enhancing fatigue properties of subterranean well drill pipe immediate the area of securement to a tool joint by providing a multi-ramp upset series on the drill pipe which, in effect, enhances fatigue resistance properties of the pipe by increasing the wall thickness on the end of the drill pipe conduit to a greater length than that found on prior art, conventional upsets adjacent the drill pipe. The increased length of this upset configuration provides a smoother transition from the thick upset adjacent the tool joint down to the thin drill pipe body.

Abstract: A method is provided for applying grooved bands of hardsurfacing on a tool joint for earth boring drill pipe. The hardfacing of the tool joint has tungsten carbide granules in an alloy steel matrix. The tool joint is rotated and an arc between an electrode and the tool joint is provided to create a weld puddle. The electrode is reciprocated parallel to the tool joint axis and the granules are fed into the weld puddle with the puddle being applied to the grooved bands around the exterior of the tool joint to a groove depth of from between about 0.75 inches to about 0.150 inches. The feed of the granules into the weld puddle is discontinued and the weld puddle is continued to be applied around the tool joint and in the grooved bands to provide a protruding substantially tungsten carbide free hardfacing surface about the outer diameter of the tool joint of from between about 0.050 inches to about 0.175 inches, and the hardfacing surface is machined down to substantially the outer diameter of the tool joint.

Abstract: A method is provided for maintaining threaded joints of a tool string to prevent jamming of the threads by rotation of a tool string required during movement of the tool string through a generally horizontal production portion and a curved bore portion of the well. Each thread joint is formed by use of an externally threaded pin and box configuration with the external diameter of the box substantially exceeding the external diameter of the pin. The cooperating threads are configured so that limited relative axial movement produces locking of cooperating threads against realtive rotation after full engagement. Relative axial movement is produced during makeup of the tool string by rotating a sleeve threadably mounted on the exterior of the pin and engagable to produce axial movement. The sleeve has an external diameter less than the box to prevent frictional engagement of the sleeve with the bore wall of the curved bore portion of the well.

Abstract: A method is provided for applying grooved bands of hardsurfacing on a tool joint for earth boring drill pipe. The hardfacing of the tool joint has tungsten carbide granules in an alloy steel matrix. The tool joint is rotated and an arc between an electrode and the tool joint is provided to create a weld puddle. The electrode is reciprocated parallel to the tool joint axis and the granules are fed into the weld puddle with the puddle being applied to the grooved bands around the exterior of the tool joint to a groove depth of from between about 0.75 inches to about 0.150 inches. The feed of the granules into the weld puddle is discontinued and the weld puddle is continued to be applied around the tool joint and in the grooved bands to provide a protruding substantially tungsten carbide free hardfacing surface about the outer diameter of the tool joint of from between about 0.050 inches to about 0.175 inches, and the hardfacing surface is machined down to substantially the outer diameter of the tool joint.

Abstract: The method of fabricating threaded pipe joints to eliminate variations in tensile strength produced by tolerance variations in the wall thickness of a pipe. Such tolerance variations are eliminated by cold forming and then machining the entire lengths of both the pin and box ends of the threaded pipe joint. A precise mathematical relationship between the root diameter of the threads and the wall thicknesses of the pin and box portions of the pipe eliminates the creation of critical areas having reduced tensile strength.

Abstract: The method of fabricating threaded pipe joints to eliminate variations in tensile strength produced by tolerance variations in the wall thickness of a pipe. Such tolerance variations are eliminated by cold forming and then machining the entire lengths of both the pin and box ends of the threaded pipe joint. A precise mathematical relationship between the root diameter of the threads and the wall thicknesses of the pin and box portions of the pipe eliminates the creation of critical areas having reduced tensile strength.