WELLHEAD STRIPPER FOR OPERATING UNDER PRESSURE Russian patent published in 2025 - IPC E21B33/02 

FIELD: obtaining oil and gas from wells.

SUBSTANCE: invention relates to oil and gas industry, namely to devices intended for wellhead sealing during lowering and lifting of pipes under pressure. Disclosed is a wellhead stripper for operating under pressure, which comprises a housing with upper and lower flanges, having a passage for passage of pipes connected by couplings, installed in the housing lower centraliser with a through hole, the diameter of which is greater than the outer diameter of the coupling, sealing element arranged in housing and having through hole, upper centralizer located above the sealing element and tightly interacting with the upper part of its through hole by the annular cylindrical protrusion, pressure nut interacting with upper centralizer, lower centralizer installed in housing under sealing element, and housing cavity is communicated with atmosphere by hole made in housing wall. Sealing element is assembled in the form of alternating metal and rubber rings. At that, under the lower centraliser in the bore of the lower flange there is a bushing with a through hole, the diameter of which is greater than the outer diameter of the coupling. At the same time the lower centraliser is equipped with a lower annular recess, and the bushing from above is equipped with an upper annular recess, and its lower annular recess is placed in the upper annular recess of the bushing with the possibility of limited axial movement in the housing relative to the fixed bushing. Bushing is equipped with an internal cavity, and in the internal cavity of the bushing there is a polyurethane ring pressing radially inward an annular retainer made of two equal halves. Each half of the retainer is equipped with a through semi-annular hole, and the end parts of the halves of the retainer, which are in contact with the couplings when lifting the pipes, are equipped with chamfers with an angle of inclination from the bottom upwards of 55°. Bushing has longitudinal channels connecting the cavity under the lower centraliser with the wellhead. When sealing the pipe sealing element, the cavity under the lower centraliser is hydraulically connected to the wellhead by means of longitudinal channels of the bushing, combined with the through annular holes of the retainer, and when sealing the pipe by the coupling sealing element, The cavity under the lower centraliser is hydraulically separated from the wellhead due to the limited radial movement of two halves of the retainer inward with compression of the polyurethane ring and divergence of the through annular holes of the retainer with longitudinal channels of the bushing.

EFFECT: improving operating reliability of the sealing element, enlarging functional capabilities of the device and increasing durability of the sealing element.

1 cl, 5 dwg