A first type of coupon holder includes an elongated core that is axially aligned with a coupon holder axis and an external surface that circumscribes the elongated core. The external surface defines coupon mounting surfaces with different radial orientations relative to the coupon holder axis. The coupon mounting surfaces are circumferentially aligned around the elongated core and have geometric centers with the same axial position along the coupon holder axis. A second type of coupon holder includes an elongated support structure that is axially aligned with a coupon holder axis and a coupon holder body positioned to have an end face in a plane transverse to the coupon holder axis. The coupon holder body has a plurality of slots to receive end portions of coupons. The slots are in a circular arrangement around the coupon holder axis and position coupons in parallel to the coupon holder axis.

A telescopic drill rod has at least two rod members disposed coaxially to one another, with the inner rod member being axially slidable relative to the outer rod member in a telescoping manner between an extended position and a retracted position. Both the inner rod member and outer rod member are equipped with joints at each end for connection to a drill head and/or another section of drill pipe. The joints also lock the inner and outer rod members in either the extended or retracted positions, and this is accomplished with a unique frusto-conical threaded engagement that is well-suited for transmitting pressure forces.

A lifting plug is for lifting a tubular column in a gas and/or oil well. The lifting plug is a one-piece component capable of being manipulated by a jaw of an oil platform elevator. The plug includes a body to be screwed onto the tubular column. The body includes two outer flanges: an upper flange and an intermediate flange. The flanges are such that the jaw of the elevator can be arranged between these two flanges. The upper flange forms a bearing shoulder for the jaw to bear on and the intermediate flange includes a bore for manipulating the plug allowing the insertion through the body of a pin emerging at two different points of the intermediate collar. The plug can be rotated by the pin while remaining engaged in the jaw.

A multi-functional jetting tool can be installed within a tubular work string, or attached to the distal or leading end of the tubular work string, in order to facilitate improved cleaning of downhole and/or subsea equipment—and particularly equipment with internal recesses, cavities or crevasses. A bull nose cap member, which can be constructed of plastic or other non-abrasive material, can be attached when the jetting tool is run on the distal end of a tubular work string. Fluid jetting ports can be selectively equipped with standard-sized or adjustable nozzles, thereby permitting customized fluid jet flow pattern from the jetting tool along the tool body in multiple directions for desired applications.

A metal sucker rod has a first end and a second end spaced apart from the first end. At least one end piece with a recess is configured to receive one of the first end and the second end of the metal sucker rod. The metal sucker rod includes an adhesive applied to at least one of a) the first end and the second end of the steel rod and b) in the recess of the at least one end piece. The adhesive is configured to secure the end piece to one of the first end and the second end.

An internally threaded bit for percussion drilling is provided, which has thread roots wider than the thread crests. A single drill bit, configured according to the present invention, can be connected to a variety of rods, having differing crest widths in their male threads. The invention enables the service life of the rods to be optimized to suit the drilling conditions at hand, without the need to manufacture and keep in inventory a correspondingly large variety of drill bits. The bit of the invention exhibits a reduced rate of ringing off, and can accept drill rods having a range of crest widths.

A gap sub assembly for electromagnetic telemetry used in downhole drilling is disclosed. The gap sub comprises a female part comprising a female mating section and a male part comprising a male mating section. The male mating section is matingly received within the female mating section and electrically isolated therefrom. One or more electrically insulating bodies secure the male part axially and torsionally relative to the female part. The electrically insulating bodies also electrically isolate the male part from the female part. The electrically insulating bodies can be installed through apertures in the female part or at least some of the electrically insulating bodies can be installed before the male mating section is inserted into the female mating section. The electrically insulating bodies can be held in place on the male mating section using a retention apparatus such as a ring, a scarf, pods or an adhesive.

A female portion is arranged to form part of a thread joint for a percussive drilling tool including a mounting sleeve having an axial end, wherein the mounting sleeve surrounds an internal cavity having an axial inner wall at the opposing end of the mounting sleeve compared to the axial end. The mounting sleeve has at least one substantially cylindrical internally threaded section having a length L.sub.1, a thread entrance positioned towards the axial end and a thread exit positioned towards the axial inner wall. A thread clearance section is positioned between the axial inner wall and the thread exit and has a length L.sub.2 and a diameter D.sub.1. A guiding section is positioned between the thread entrance and the axial end of the sleeve and has a length, L.sub.3, wherein 0 mm<L.sub.3-L.sub.2<12 mm.

A drill string rod includes an elongate central rod portion. The central rod portion has a hollow-cylindrical shape with an inner first diameter (d.sub.rod) and an outer second diameter (D.sub.rod). The male end includes a spigot having a base projecting axially from a shoulder that axially separates the spigot and the central rod portion. The female end has a sleeve portion that fits to the spigot. An inner thread of the sleeve portion is attachable to an outer thread of the base of the spigot of a further drill string rod. In a radial plane to the longitudinal axis of the drill string rod, the base of the spigot is defined by an outer third diameter (D.sub.spigot) and an inner fourth diameter (d.sub.spigot) and the sleeve portion is defined by an outer fifth diameter (D.sub.sleeve) and an inner sixth diameter (d.sub.sleeve), wherein the second diameter (D.sub.rod) is >60 mm.

Threaded connection for exploration and production of a hydrocarbon well, said threaded connection including a pin including an outer pin surface provided with an external thread, a box including an inner box surface provided with an internal thread for mating with the external thread during rotational make-up of the threaded connection, and an anti-rotation device to allow relative rotation between the pin and the box in a make-up rotation direction and prevent relative rotation between the pin and the box in an opposite break-out rotation direction, wherein the pin and the box extend along a longitudinal axis, the anti-rotation device includes a releasable mounted first anti-rotation member which is arranged in a first radial recess provided in one of the outer pin surface and the inner box surface, and a second anti-rotation member provided at the other of the outer pin surface and the inner box surface.