GB855053A - Integral well head unit and method of fabricating the same - Google Patents

Abstract

855,053. Oil wells. OIL CENTER TOOL CO. May 27, 1959 [Aug. 18, 1958], No. 18034/59. Class 85. [Also in Groups XXVI and XXIX] A well-head unit comprises a body 12 having a bore 14 intersected by transverse tapered openings 24, 26, 28 which receive non-rotatable valve bodies 50. As shown, the valves are of the plug type, but other types of valves may be used. Each valve body 50 has an outer surface tapered to complement the surface of the respective opening 24, 26 or 28 is threaded to receive a locking-ring 80 anc has a cylindrical bore 58 which receives a plug 60 having a bore for alignment with the bore 14, and a spindle 66 with a squared end 68 for an operating key. The plug 60 is retained in position by a screw plug 64. The valve body 50 is positioned, with the bore 54, 56, 14 in line, by a key and key-way 88 90. The junctions between the bores 14, 54 and 14, 56 are sealed by two grooves 100, 102 which encircle each of the bores 54, 56 O-sealing rings 104, 106 being placed in the grooves. The ring 104 in each of the oute grooves 100 is spaced from the inner wall o the groove, a passage 108, 110 serving for the injection of plastic into this space to rende the seal ring effective. The bores 16, 18 in the branches of the body 12 are likewise provided with non-rotatable valve bodies. In a modification, the tapered surfaces of the openings 24, 26, 28 and the bodies 50, are stepped, comprising cylindrical parts of successively decreasing diameter, joined by tapered parts. Grooves running circumferentially around the body 50 in the tapered parts thereof, receive tapered metal sealing rings which are made effective as the nut 80 is tightened. An O-ring surrounds each of the bores 54, 56, and plastic sealing material is injected into a circumferential groove in the body and, through a communicating channel, into a space between one of the metal sealing rings and an annular stop ledge in the bore 24. The well-head unit may be designed for dual tubing strings; the bores 14 may be fitted with a steel liner; and the unit may be combined, Fig. 8, with a tubing hanger 214 retained on its seat 218 by cone-headed screw pins 222. Laterally extending bores 230, 232 connect with the bore 212 beneath the hanger 214 and have transverse openings 234, 236 to receive valve assemblies as described above. The openings 240, 242 also receive valve assemblies. Advantageous residual stresses are produced in the body 12 by heating, cooling, re-heating, quenching by spraying the bore 14 and subsequent immersion, and tempering by re-heating, temperatures and times being given. Alternatively, body is subjected to high hydraulic pressure to stretch the inner wall of the bore beyond its yield point, so that this inner wall region is under compression when the hydraulic pressure is removed.