WELL-HEAD PACKER

oil and gas production, geological prospecting. SUBSTANCE: invention is intended for tightness test of well-head part of casing string together with anti-outburst equipment when drilling oil and gas wells. Well-head is made of body, sealing unit and tail part. Sealing unit is composed of two radial sealing rings with collars and sloping outer chamfers to put packer into well-head. Sealing rings are separated by washer with bevels geometrically corresponding to surfaces of collars of sealing ring. Washer has ducts to feed fluid from upper sealing ring to lower one. Spacing sleeve limits degree of compression of sealing rings by rests-stabilizers. Upper rest-stabilizer has ducts to feed fluid from well clearance into space of upper sealing ring. Tail part is provided with circular row of through radial holes with thread for setting of stopping screws fixing tail part in annular groove of body. Packer is lowered on drilling pipes. Pressure is formed in well clearance. Packer seals zone of hydrostatic test. Sealing rings take original shape after stop of feed of hydrostatic test fluid. EFFECT: increased functional reliability of packer in process of hydrostatic test of well-head part of casing string together with anti-outburst equipment. 1 dwg