A coupling including a tubular body with two ends of the body each including a portion of internal threading for joining to a tubular element, and a central portion separating the two ends each including a portion of threading and having a wall thickness greater than the wall thickness of the ends of the body. The coupling includes an extension segment that extends from one of the ends of the tubular body, after the portion of internal threading, the extension segment having same outside diameter as that of the tubular body and an inside diameter greater than or equal to that of the portion of internal threading. Moreover, the extension segment includes a housing, including an opening onto an external surface of the coupling, in which an electronically responsive identification tag is housed.

A lubricant film-forming composition includes as a composition: 40 to 80 mass % of a base oil consisting of one or more selected from pentaerythritol fatty acid ester and trimethylolpropane fatty acid ester; 5 to 20 mass % of a solidifying agent consisting of paraffin wax; and 10 to 40 mass % of a solid lubricant consisting of one or more selected from alkali metal salt of hydroxystearic acid and alkali earth metal salt of hydroxystearic acid. A total content of the base oil, the solidifying agent, and the solid lubricant is 85 mass % or more and 100 mass % or less, and the lubricant film-forming composition does not contain heavy metals.

In a threaded joint for steel pipes comprising a pin (1) and a box (2), each having a threaded portion (11 or 21), a sealing surface (13 or 23), and a shoulder surface (14, 15 or 24, 25), the sealing surface (13) of the pin (1) is formed by a tapered surface, and the sealing surface (23) of the box (2) is formed by a first curved surface portion with a large radius of curvature in the range of 15-120 mm, a tapered surface portion, and a second curved surface portion with a large radius of curvature again in the range of 15-120 mm.

A threaded connection connecting a pair of pipes includes a pin and a box. The pin has a male thread on its outer diameter. The box has a female thread on its inner diameter, the female thread corresponding to the male thread. The male thread includes constant-thread-width and varying-thread-width portions. The constant-thread-width portion has a constant thread-groove width. The varying-thread-width portion has a thread-groove width equal to or larger than the groove width of the constant-thread-width portion and gradually increasing, from the constant-thread-width portion toward the tip of the pin. The female thread includes constant-thread-width and varying-thread-width portions. The constant-thread-width portion has a constant thread-ridge width. The varying-thread-width portion has a thread-ridge width equal to or larger than the thread-ridge width of the constant-thread-width portion and gradually increasing from the constant-thread-width portion toward the center of the box.

An affordable family of threaded pipe connections is disclosed, that have desired strengths and service torques, for a wide range of sizes and services.

A tubular member for threadably engaging another tubular member to form a tubular string includes a first end including a helical female thread formed in an outer surface of the tubular member, wherein the female thread includes a slot extending radially inwards from the outer surface, and a root extending radially inwards from the slot, wherein the root has a maximum width that is greater than a maximum width of the slot, a second end opposite the first end and including a helical male thread formed on an inner surface of the tubular member, wherein the male thread includes a shank extending radially outwards from the inner surface, and a notch extending radially outwards from the shank, wherein the notch has a maximum width that is greater than a maximum width of the shank.

A threaded connection for steel pipes having improved sealing performance is provided. A threaded connection (10) for steel pipes includes a pin (10) and a box (20). The pin (10) includes a nose (11), a pin shoulder surface (12), a pin sealing surface (13) and a male thread (14). The box (20) includes a box shoulder surface (22), a box sealing surface (23) and a female thread (24). When the position of the portion of the pin sealing surface (13) that first contacts the inner periphery of the box (20) during make-up defines a seal position (P), the distance between the seal position (P) and the end of the male thread (14) adjacent to the pin sealing surface (13) as measured in the pipe-axis direction is denoted by x, and the distance between the tip of the pin (10) and the end of the male thread (14) adjacent to the pin sealing surface (13) as measured in the pipe-axis direction is denoted by L, then, x/L is not smaller than 0.4 and not larger than 0.55.

The disclosure is related to methods for testing and/or validating drill pipe and threaded and coupled connectors for use in subsea intervention system riser applications (open-water and through-riser). The methods are novel applications for testing and/or validating drill pipe and threaded and coupled connections that conform to Annex E of API 17G.

A leak-resistant pipe connection has an annular seal bulge on a pin end of the connection and a tapered seal area adjacent a secondary box shoulder of a box end of the connection. The annular seal bulge is coined on contact with the tapered seal area on initial make-up of the connection which provides a metal-to-metal seal that is very resistant to high-pressure fluid leakage even after the connection is subjected to extreme shear and tensile stresses.

A threaded connection for large diameter steel pipe exhibits high torque resistance and high sealability and, at the same time, provides a shear resistance that suits the size of the steel pipe to be connected. The threaded connection includes a tubular pin provided on a tip of a steel pipe with large diameter, and a tubular box 20 adapted to be drawn up on the pin as the pin is screwed in. The pin includes a male threadform made with a taper thread. The box includes a female threadform made with a taper thread. Each of the threadforms are wedge threads and have a dovetail-shaped cross section. The male threadform is designed such that the width of the thread in an end region of the male threadform closer to the tip is set to a size corresponding to the size of the pipe body of the steel pipe.