The invention relates to a threaded cylindrical member, which may be used for a segmented drilling tube. The member has opposing first and second ends and a central axis between said ends. The first end is threaded with a pin thread comprising a pressure flank, a crest and a root. The second end is threaded with a box thread comprising a pressure flank, a root, wherein said pin and box threads are configured whereby when threaded together a portion of the root of said pin thread is out of contact with the crest of said box thread to leave gap therebetween. The secondary geometries of the pin and box threads are configured to generate an interference fit between the pin and box threads. The roots and crests of the pin and box threads define parallel tapering conical frustrums that differ from each other in their taper angles.

A coupled pipe connection system may include a coupling with internal threads adapted for joining two pipe sections by threaded engagement of external pipe threads with the internal coupling threads. A torque ring may be disposed within the coupling and between the first pipe and the second pipe. The torque ring may an outer cylindrical surface, at least a portion of which may include a plurality of tapered threads engaged with and tapered to match a mid-length axial section/J-space of the inner threads of the coupling. Annular faces of the torque ring may be beveled inwardly or outwardly and adapted for mating engagement with corresponding beveled annular faces of the pipe ends. Torque rings of gradually decreasing axial lengths may be incrementally swapped out as the number of make-up cycles increases. Couplings having internal shoulders of gradually decreasing axial lengths may be used instead of torque rings.

A tubular connection comprising a longitudinal axis, a pin member comprising a distal pin end, a tapered pin thread having a constant pin taper angle α.sub.1 with respect to the longitudinal axis, and a pin sealing surface located between the pin thread and the distal pin end, and a box member comprising a distal box end, a box sealing surface, and a tapered box thread having a constant box taper angle β.sub.1 with respect to the longitudinal axis and located between the box sealing surface and the distal box end, and wherein the pin thread is configured to cooperate by make up with the box thread along a cooperating area, while having a radial thread interference between the pin thread and the box thread along at least part of the cooperating area, the pin sealing surface and the box sealing surface are configured to contact each other upon make-up in a sealing manner while forming a metal to metal seal, and the pin taper angle α.sub.1 is larger than the box taper angle β.sub.1.

A threaded connection for steel pipe is provided that can be made up quickly and appropriately. The threaded connection includes a steel pipe 20m, a steel pipe 20f, and a coupling 50 for connecting the steel pipes 20m and 20f. The pipe bodies 21m and 21f of the steel pipes 20m and 20f include annular marking grooves 23m and 23f, respectively, formed on the outer peripheries of the pipe bodies 21m and 21f.

A threaded connection between adjacent drill string components comprises a threaded female connection end adapted to receive a correspondingly threaded male connection end, the two ends each having first and second portions of different tapers. Tubular members, drill string tools and other drill string components comprising the female or male ends described herein are also provided.

A threaded tubular connection comprises a first tubular component and a second tubular component. The first tubular component includes a female portion defined on an interior surface of the first tubular component. The female portion includes an inner threaded portion and an outer threaded portion which are offset radially with respect to a longitudinal axis of the first tubular component by a first shoulder. The second tubular component includes a male portion defined on an exterior surface of the second tubular component. The male portion is to be inserted into the female portion, and includes an inner threaded portion and an outer threaded portion which are offset radially with respect to a longitudinal axis of the second tubular component by a second shoulder. The second shoulder is to abut the first shoulder once the male portion is connected to the female portion.

This invention builds up on technical features and on the industry experience with the use of Merlin™ family connectors. In addition to friction, structural means utilized to transfer high torsional loads include keys and may also include: interlocked thread systems, shear pins, dog-clutch teeth and splines, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin™ family connector designs to increase they torque transfer capacities may be also feasible.

A threaded joint for casing pipes and production pipes has a threaded portion, and a metal-metal type sealing assembly structure in the form of a combination of sealing elements which provide 100% effective functioning of the joint under compression and tension, inter alia under the effect of internal and external fluid pressure, by observing the size ratio criteria of a ball-and-cone type seal, in which a radial sealing surface has two consecutively arranged toroidal surfaces which, in the event of axial contact between flanges, form, together with a mating sealing surface of a female member, two seals which remain tight under any combination of loads. The technical result of the group of inventions is an increase in the reliability of the threaded joint under the effect of static and variable operating loads, including external pressure, compression, twisting, and combined loads during the bending and turning of a pipe string, wherein the pipes can be used in the construction of wells having a degree of deviation of up to 13°/10 m.

A threaded tubular connection comprises a first tubular (12) component and a second tubular component (14). The first tubular component (12) includes a female portion (10) defined on an interior surface of the first tubular component. The female portion includes an inner threaded portion (16d) and an outer threaded portion (16b) which are offset radially with respect to a longitudinal axis of the first tubular component by a first shoulder (26). The second tubular component (14) includes a male portion (18) defined on an exterior surface of the second tubular component. The male portion is to be inserted into the female portion, and includes an inner threaded portion (18d) and an outer threaded portion (18b) which are offset radially with respect to a longitudinal axis of the second tubular component by a second shoulder (28). The second shoulder is to abut the first shoulder once the male portion is connected to the female portion. The threaded tubular connection comprises an inner short length fluid tight seal.

A threaded connection includes a pin and a box. The pin includes, in the order from a free end side of the pin toward a tubular body side thereof, an inner sealing surface, an inner male threaded portion, a shoulder portion, an outer male threaded portion, and an outer sealing surface. The box includes, in the order from a tubular body side of the box toward a free end side thereof, an inner sealing surface, an inner female threaded portion, a shoulder portion, an outer female threaded portion, and an outer sealing surface. Between the inner sealing surface and the inner female threaded portion of the box, an inner groove along a circumferential direction is provided, and some threads of the inner male threaded portion of the pin are contained in the inner groove.