FLANGE CONNECTION OF WELLHEAD EQUIPMENT (OPTIONS) Russian patent published in 2021 - IPC E21B33/38 F16L23/36 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry and can be used in the repair of a well for fixing the wellhead flange during well operation. The flange connection of the wellhead equipment contains a support and wellhead flanges with holes for studs or bolts for mounting, an O-ring installed between the flanges in grooves with conical surfaces. According to the first variant, the bolts for fastening are made with segment heads, which exclude mutual turning between each other when tightening the nuts. In this case, the segment heads form a ring with an outer diameter of D_o and an inner diameter of D_i. Moreover, D_o corresponds to D_o = D_bc-1.5×d, and D_i corresponds to D_i = D_bc + 1.5×d, where D_bc is the diameter of the bolt circle, mm, d is the diameter of the bolts, mm. In this case, the outer circumference of the segment, L₁ of one of the segment bolt heads equal to each other is determined by the dependence L₁ = π× D_o/n, where π = 3.14, D_o is the outer diameter of the segment heads forming the ring, mm, n is the number of bolts with segment heads. The internal circumference of the segment, L₂ of one of the segment bolt heads equal to each other is determined by the dependence L₂ = π× D_i /n, where π = 3.14, D_i is the outer diameter of the segment heads forming the ring, mm, n is the number of bolts with segment heads. In this case, the segment bolt heads with their lower ends are in contact with the wellhead equipment used throughout their entire area, and the height a of the segment bolt heads is assumed to be equal to 0.8 of the height b of the nuts, and the bolts and nuts have a large thread pitch of 3.0-4.0 mm. According to the second option, blind threaded holes are made in the wellhead flange, the number of which is equal to the number of holes in the support flange. Moreover, when sealing the flange connection, studs are screwed into the blind threaded holes of the wellhead flange. The depth of each blind threaded hole is 1.25 times greater than the thread height of each nut, after pre-installing the O-ring in the groove with the conical surface of the support flange. At the same time, the studs and nuts have a large thread pitch of 3.0-4.0 mm.

EFFECT: reduction in the assembly time of the flange connection of the wellhead equipment, simplification of the maintenance of the device in operation, reduction in the duration of the time of fastening nuts to studs or bolts and reduction in the metal consumption of the structure.

2 cl, 7 dwg