SEALING DEVICE FOR TUBING-CASING ANNULUS ON WELL HEAD Russian patent published in 2015 - IPC E21B33/04 

FIELD: oil and gas industry.

SUBSTANCE: device includes a cylindrical housing with a flange at the top end face, an internal annular bore in upper part, and axial and radial central channels for side branch pipes. In the internal annular boring of the housing the sealing unit interacting with the coupling of the internal casing string is placed. The companion top flange interacting with the sealing unit is attached to the housing flange. In the lower part of the housing there is an external connecting thread by means of which it is connected to the reducer. In the reducer the support ledge with boring located under the housing is implemented. The centralizer of internal casing string implemented as the cylindrical bushing with through axial channels interacts with the bearing ledge. Connection of the reducer with the coupling of the external casing string is made using the branch pipe. Diameter of the hole of the branch pipe Dhb complies with the relation: Dbb > Dhb > Ditp, where Dbb - diameter of boring of the bearing ledge; Dhb - diameter of the hole of the branch pipe; Ditp - internal diameter of the top pipe of the external casing string.

EFFECT: decrease of expenses and improvement of reliability of performance.

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