METAL-TO-METAL-TYPE SEAL IN COLUMN HEAD FOR UNDERWATER WELLS Russian patent published in 2019 - IPC E21B33/35 E21B33/43 

FIELD: technological processes.

SUBSTANCE: invention relates to sealing of annular gaps between conductor and installed in it suspension of technical pipe string during operation of underwater wells. Disclosed is a seal, made with three-step annular seals of metal-metal type and having housing 5, pusher 17 with shear transport element 18, two fixing rings 23, 29 and lock 35. Housing 5 comprises outer sealing elements 6 including lower 7, middle 8 and upper 9 sealing bands, conjugated with conductor 1, forming the first labyrinth system. Housing 5 comprises inner sealing elements 10 including bottom 11, middle 12 and top 13 sealing bands coupled with suspension 2 to form second labyrinth system. Said belts 11, 12, 13 can contact with support surface 3 of suspension 2 made at angle 4 equal to not more than 10° relative to well axis. Surfaces formed by tops of belts 11, 12, 13, and surfaces formed by tops of belts 7, 8, 9 have angles of the same range "X" with the well axis. Also, housing 5 comprises contact surfaces 14, 15, which are located one relative to the other at angle of 16. Pusher 17 comprises contact surfaces 19, 20, one of which has groove 21 for water discharge. Surfaces 19, 20 are located one relative to the other at angle 22 equal to angle 16 of surfaces 14, 15 or less. Pusher 17 has the possibility of fixing conductor 1 relative to suspension 2 from axial displacement relative to each other by means of rings 23, 29. Ring 23 can interact with suspension 2, and ring 29 can interact with conductor 1. Each of rings 23, 29 has small-tooth toothed profiles, and grooves – small-module teeth. Width 28, 34 of rings 23, 29 is smaller than width 27, 33 of grooves 25, 31. And profiles can be fixed on teeth, and rings 23, 29 have possibility of interaction with lock 35.

EFFECT: higher sealing reliability of conductor and string suspension.

1 cl, 6 dwg