METHOD OF CONNECTIONS OF WELLHEAD WITH SUPPLEMENTARY STRINGS (VERSIONS) Russian patent published in 2011 - IPC E21B33/03 E21B33/04 

FIELD: oil and gas production.

SUBSTANCE: wellhead assembly is dismantled up to a casing head CH with a bridge plug mounted in a supplementary string SS. A portion of a zero nipple is cut off and removed, and the CH is set with a skip hanger being detached. The CH is renewed, and the skip hanger and primary seals are fixed therein. If a cement stone is placed at the level of an upper border of the SS, upper portions of the production casing and the supplementary string are cut off, and a spacer ring is placed in between and covered with a sealing compound, and a thrust bush is threaded on the SS. If the cement stone is placed below a false coupling of the SS, it shall be unscrewed and replaced by a twin pin body whereon a landing adapter is threaded with its bottom resting against in an end face of the cut off production casing and with its top placed in a seat for secondary seals; thereafter an assembly of a lower "ТГ" and secondary seals of the proper dimensions is mounted. If the cement stone is placed in a space between the end face of the SS and the false coupling of the SS, tops of the PC and the SS are cut off, while a tube space is filled with a sealing composition. An assembly of a renewed bottom "ТГ" and the secondary seal is mounted on the renewed CH. The other wellhead assembly is installed as specified by a routine procedure.

EFFECT: maintainability enhancement.

3 cl, 4 dwg