Abstract: A drill pipe protector having a tubular sleeve that is attached to a section of drill pipe and resides over the outer diameter of the drill pipe while moving within an associated well casing or well hole. The sleeve has low-friction end pads positioned on the ends of the sleeve to reduce friction between the ends of the sleeve and the end of an adjacent thrust bearing collar used to hold the sleeve in place on the drill pipe.

Abstract: A stabilizer especially adapted for use with an drill string having an eccentric drilling element, such as a bi-center bit. The stabilizer has a pair of circumferentially displaced blades that lie in a common circumferential plane and extend from a rotatable sleeve supported on the stabilizer body, as well as a stationary blade. The rotating blades are aligned with the stationary blade when in a first circumferential orientation and are disposed so that the mid-point between the rotating blades is located opposite the stationary blade, thereby providing full-gauge stabilization, when the rotating blades are in a second circumferential orientation. A magnetic systems senses the circumferential orientation of the rotating blades and transmits the information to the surface via mud pulse telemetry. A piston actuated by the drilling mud locks the rotating blades into the active and inactive positions.

Abstract: A centraliser (1) has a substantially annular body (6), a substantially cylindrical bore extending longitudinally through the body (6), and at least one roller ball (29). The roller ball (29) is preferably secured to the centraliser (1) in a manner which enables the roller ball (29) to rotate in all directions with respect to the centraliser (1), and one roller ball (29) is secured within at least one aperture (9; 109) provided in the sidewall of the body (6). Preferably, an assembly (27, 28, 39; 127, 128, 139) is provided to house the rollerball (29) within the at least one aperture (9; 109), and the roller ball (29) may be arranged to project either outwardly or inwardly from the sidewall.

Abstract: A centralizer having a first group of rollers (5) for reducing friction between the centralizer and an oil field tubular (7) and a second group of rollers (4) for reducing friction between the centralizer and the wall of a well. The axles of the first group of rollers (5) are generally aligned with the axis of the bore (2) to reduce rotational friction. The axles of the rollers of the second group of rollers (4) are generally transversed to the bore (2). The arrangement reduces rotational and axial drag between an oil field tubular (7) and the walls of a well, particularly when initiating rotation of an oil field tubular.

Abstract: A centralizer for engagement with a pipe exterior surface to be positioned downhole in a wellbore. The centralizer includes a collar which can be fastened with set screws or other connector to the pipe exterior surface. A body is engaged with said collar for containing axial movement of the body within a selected portion of the pipe exterior surface while facilitating rotational movement of the body relative to the pipe exterior surface. The engagement between the collar and the body permits rigid attachment of the collar to the pipe while permitting the centralizer to free-float relative to the pipe.

Abstract: The present invention provides a roller sub for use downhole in oil or gas wells as part of a toolstring or drill string to reduce friction between the string and wellbore. The roller sub is a modular assembly of parts which assemble together to trap the roller wheels in place between them, avoiding need for grub screws to fasten the individual wheels and rendering the roller sub very compact.

Abstract: A centralizer for laterally positioning an instrument in an opening larger in diameter than the diameter of an opening through which the centralizer can freely pass. The centralizer includes spring blades affixed at one end to an outer surface of the instrument and extending axially to a stop collar rotatably positioned on the outer surface of the instrument. A latch is operatively coupled to the stop collar and is adapted to enable rotation of the stop collar about the instrument upon release of the latch.

Abstract: A centralizer which comprises a pair of annular bands (2, 3) which are spaced apart by a plurality of hollow members (4 to 9) characterized in that the hollow members (4 to 9) are each provided with at least one window (24, 25, 26) having a roller (12, 13, 14) freely rotatably mounted therein.

Abstract: A friction and/or torque reducing drillstring component has a one-piece mandrel body 5 with a mandrel body recess 13c considerably smaller than mandrel upper neck 13a and mandrel body lower neck 13b, dressed with an outer sleeve 18 which is interlocked with a two-piece inner bearing 20 through several integral dove-tailed splines 22b and grooves 22a. The combination of the outer sleeve 18 and inner bearing 20 is restricted in vertical movement over the said mandrel body 5 by an integral, optionally spirally, bladed first stop 15 and a removable second stop 16. The removable second stop 16 is locked onto the mandrel body upper neck 13a by means of threaded retaining bolts 24. Once the second stop 16 is removed, the one-piece outer sleeve 18 is retractable over the mandrel body upper neck 13a to allow the removal of the two-piece inner bearing 20. A second inner bearing 155 may also be provided.

Abstract: A casing centraliser and assembly comprising a tubular and a centraliser, the centraliser comprising a plastics material.

Abstract: A cavity positioning tool is provided that includes a head piece adapted to receive a downhole string having a longitudinal axis. A plurality of blunt arms are coupled to the head piece. The blunt arms are operable to be radially extended outward from a first position of substantial alignment with the longitudinal axis to a second extended position.

Abstract: A friction reducing tool for drilling applications having a plurality of rollers for about the periphery of the tool (3). The rollers (4) have extensions (7) which locate within cavities (8) to prevent the rollers from passing from cavity (10) to the exterior of the tool. The tool is formed in multiple parts (3a and 3b) having interengaging tongues (5 and 6) which are joined together by passing a rod (15) through bore (13). A groove (14) is provided in outer component (2) to enable rod (15) to be inserted in bore (13).

Abstract: The friction-reducing drill pipe component in the form of a sub (10) is adapted to form part of a drill string. The sub (10) comprises a tubular mandrel (12) having first and second ends for connection to adjacent components of the drill string. A sleeve (18) is mounted on the mandrel (12), and first and second stops on the mandrel (16, 20) restrain the sleeve (18) against axial movement relative to the mandrel (12). One of the stops (20) is removable or retractable to permit the sleeve (18) to be removed over the first end of the mandrel.

Abstract: A method and apparatus which inserts and withdraws tubing from pipes without bending or kinking the tubing. The method and apparatus may be employed to insert and withdraw tubing to depths greater than ever possible before. The method involves using skate apparatuses to reduce coiling and friction of the tube. Advantageously, the apparatus is portable, easily handled, and adaptable to handle tubing of differing diameters.

Abstract: An apparatus for assisting the advancement of a work string. In the preferred embodiment, the work string is concentrically disposed within a highly deviated tubular member. The apparatus comprises a cylindrical member having a first half clamp and a second half clamp having an arcuate inner portion, with the first half clamp and second half clamp being connected with a hinge. The apparatus further includes a first housing attached to the first half clamp and a second housing attached to the second half clamp. The apparatus further comprises a first roller inserted into the first housing and a second roller inserted into the second housing. In the preferred embodiment, the first and second rollers are spherical. The apparatus may further comprise a first deflector plate operatively associated with a first side of the first housing and the second housing. The first deflector plate has a first end adjacent the cap member and a second end adjacent the first half body so that an angled end is formed.