THREADED JOINT FOR HEAVY-WALLED OIL COUNTRY TUBULAR GOODS

摘要

The purpose of the present invention is to provide a threaded joint for an ultra thick oil well pipe, the joint being able to maintain sealability and prevent the occurrence of galling in a state where a high compressive force is applied and high external pressure acts on the joint. A surface of a pin (3) that serves as sealing parts (13, 11) and a surface on a box (1) side respectively have a convex curved surface and a tapered surface. With respect to the pin (3), a pin seal thickness ts is no more than 15mm, a shape parameter ts/D (D is the outer diameter of a pin original pipe section) is at least 0.045, and a total screw length ratio L/t (L is the pin total screw length, and t is the thickness of the pin original pipe section) is no more than 4Ø