Vallourec Oil and Gas France

Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Russell Elder

Bertrand Maillon

Yousuke Oku

Masaaki Sugino

Tatsuya Yamamoto

A threaded tubular connection including a first tube and a second tube is provided. The first tube includes a pin member which extends from an end of a main body of the first tube to a terminal end of the first tube. The second tube includes a box member which extends from an end of a main body of the second tube to a terminal end of the second tube. A cross-sectional area of a pin critical cross-section is within approximately &#xb1;5% of cross-sectional area of a box critical cross-section of the box member. The cross-sectional areas of each of the pin and box critical cross-sections are within approximately &#xb1;5% of the sum of the cross-sectional areas of a box intermediate critical cross-section of the box member and a pin intermediate critical cross-section of the pin member.

Tubular threaded connection

In a screw joint for a steel pipe, a taper angle of a tapered surface of a pin is substantially the same as a taper angle of a tapered surface of a box. In addition, the pin and the box interfere with each other in a radial direction while a seal surface of the pin and a seal surface of the box contact each other in a process of make-up between a male screw portion and a female screw portion, and at least apart of the seal surface of the pin comes into close contact with at least a part of the seal surface of the box over the entire circumference. Moreover, a contact pressure amplification mechanism, which increases a contact pressure between the seal surface of the pin and the seal surface of the box at the completion of the make-up, is further provided.

Screw joint for steel pipe

A threaded tubular connection includes a first tube and a second tube. The first tube includes a pin member and the second tube includes a box member. A cross-sectional area of a pin critical cross-section is within approximately &#xb1;5% of cross-sectional area of a box critical cross-section of the box member. The cross-sectional areas of each of the pin and box critical cross-sections are within approximately &#xb1;5% of the sum of the cross-sectional areas of a box intermediate critical cross-section of the box member and a pin intermediate critical cross-section of the pin member. In a made-up state, a first seal surface on the pin engages a second seal surface on the box in a radial direction so as to form an off-center fluid tight seal that extends in an axial direction of the threaded tubular connection.

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Houston, TX, United States of America

Russell Elder