FACILITY TO SEAL WELL-HEAD Russian patent published in 2001 - IPC

FIELD: drilling and operation of wells. SUBSTANCE: proposed facility includes body, cover, sealing member, sleeve with space for sealing member. Piston has surface for placement of sealing member , working chamber and return chamber. Hydraulic conduits communicate working and return chambers with source of hydraulic pressure. Second sleeve is mounted in space of body. Unloading compensation chamber is formed between first sleeve and cover. It communicates with throttling valve by means of hydraulic conduit. Facility has locks-bearings. Pressure is applied for sealing of well-head. Piston goes upwards compressing sealing member which extends into hole in body and embraces tool or shuts off free well-head. Axial effort from piston and well-head pressure is partially transmitted through sealing member and sleeve to bearing. Main effort is compensated by pressure in unloading chamber on upper part of nut relieving bearing. Some fluid is forced through throttling valve, lubricating, washing and cooling bearing. With loss of pressure piston goes downward and sealing member releases tool. EFFECT: simplified arrangement of well-head binding, reduced dimensions, simplified attendance and operation. 8 cl, 3 dwg