A TIGHT THREADED JOINT OF OIL FIELD PIPES

摘要

The invention relates to oil and gas well building and can be used in pro cess casing pipes. The inventive sealed threaded joint for oilfield pipes co mprises female and male pipes provided with conical threads and with sealing and thrust surfaces. The sealing surfaces are brought into contact in a rad ial direction. The sealing surfaces are embodied on the external surface of three end section of the male pipe and on the internal conical surface of th e female pipe on the section between the conical thread and a pipe body, res pectively. The thrust surfaces are embodied on the male pipe in the form of a conical end face, the angle of cone of which is of 5°<=.beta.<=25°in the direction of the conical thread axis, and of a mating end conical surfa ce on the female pipe which is embodied on a section where the first conical surface of said pipe transforms into the body thereof, respectively. The co nical thread profile has a negative angle along the bearing face. The height of the thread profile of the male pipe is less than the height of the threa d profile of the female pipe. The sealing surface of the end section of the male pipe at the beginning and at the end of the conical radial seal is shap ed in the form of a sphere. Said invention makes it possible to increase the reliabilityand tightness of the joint in bending deformation conditions.