COMBINED SEAL FOR COLUMN HEAD IN WELL ON SHELF Russian patent published in 2019 - IPC E21B33/35 E21B33/43 

FIELD: sealing.

SUBSTANCE: invention relates to means for sealing of annular gaps between conductor and installed in it suspension of technical string of pipes during operation of wells on shelf. Combined seal is made with two-stage seals and has housing 7 of H-shaped profile in form of two rings 8, 9 with transverse web 10 for their connection and pusher 15. Housing 7 comprises three contact surfaces: inner surface 11 and outer surfaces 12 and 13 in contact with landing conical surface 5 of suspension 3 with equal inclination angle 6 relative to well axis to 10 degrees. Contact length of surface 11 is greater than the total contact length of surfaces 12 and 13. Surface 11 and surfaces 12 and 13 form the first stage of metal-metal seal. Besides, housing 7 is provided with thrust 14 with locking spring ring 16 fitted on pusher 15 to retain housing 7 from axial displacement downwards. Between housing 7 and pusher 15 there is side gap 17 to allow displacement of housing 7 relative to pusher 15 in radial direction. Besides, pusher 15 is rigidly connected with housing 7 by shear element 18. Between pusher 15 and housing 7 there is an external seal of high elasticity 19 for sealing of the surface of conductor 1, and for sealing of suspension 3 there is an internal sealant of lower elasticity 20. Sealant 19 and seal 20 form together second stage of seal – elastic elastomer seals. Besides, pusher 15 is provided with retainers in form of split resilient rings 21 and 22 to interact with fixing slots 2 and 4 and lock 23.

EFFECT: improving sealing reliability of conductor and suspension of technical pipe string during well operation on shelf and simplification of technological operations.

3 cl, 3 dwg