DEVICE FOR CONNECTION OF CASING STRINGS AT WELL HEAD Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this can be used in designing new equipment for connection of casing strings to surface coupler at well head. Device is additionally provided with secondary sealing components which are located between cylindrical surfaces in annular clearance of casing string heads. Secondary sealing components interact with spacer nut through thread on its external cylindrical surface. This in combination with casing string head creates threaded pair. For secondary sealing components of Christmas tree equipment, made in end face of internal casing string head is cylindrical supporting shoulder. For circulation of fluid, slots are made in internal cylindrical surface of external casing string head. Slots ensure circulation of fluid in washing and cementation of casing string even in case when seating cones of casing string heads are interacting with each other. Clearance between casing string heads after washing of surfaces is sealed off by means of flexible component with help of spacer shaped rings and spacer nut with thread in its external surface. Nut is also provided with hole in its end face for using wrench. Application of device allows for reducing amount of metal needed to manufacture, improves reliability and upgrades performance characteristics. EFFECT: higher efficiency. 1 dwg