GB1274694A - Underwater well completion method and apparatus - Google Patents

Abstract

1,274,694. Wells. ROCKWELL MFG. CO. 16 Oct., 1969 [22 Jan., 1969], No. 50956/69. Heading E1F. An underwater well is completed by sinking into the seabed (e.g. by jetting) a conductor casing 10 with a casing head 11, and a conductor riser 12 attached to it by means of a breech block joint (Fig. 1A, not shown). Drills are then passed down the conductor riser to drill holes for one or more inner casings which are suspended on hangers and cemented in place. For example in Fig. 1 three inner casings 40, 50, 60 are shown suspended on hanger heads 11, 41, 51. The casings may merely rest on the hanger heads, as by lugs 44 in the case of the casing 40, or be clamped by expanding latches 55, 65 as on the casings 50 and 60 in Fig. 1. Risers are connected to the casings by breech block joints 46, 54, or by left-handed thread 64 in the case of the inner, production riser. The well is completed by attaching a blowout preventer to one of the risers and running tubing through it. The tubing is then latched to a hanger in the innermost casing, and the blowout preventer and the other risers are removed. For example the innermost riser may be removed and the blowout preventer fitted to the riser 53 down which an orientation bushing 74 with guide surfaces 75 is run. A tubing hanger 80 (Fig. 3) carrying tubing strings 90, 91 and an access nipple 92 is then run down the riser 53 on a running tool 93 through which pass nipple 95 and another nipple (not shown), connected to handling nipples 94, 96. The hanger 80 is fixed by latches 86, 87, and the installation is presuretested, using bores 99 in the tool 93. Packers may be installed in the tubing strings and tested and the handling strings 94, 96, the tool 93 and the risers 43, 53 removed to leave the well as in Fig. 4. The well may be fitted with a Christmas tree adapter (e.g. 100, Fig. 6, not shown, which engages the breech block joint 54). The adapter may then be capped or a Christmas tree added, and the riser 12 removed. In another embodiment, Fig. 7, tubing strings 270, 271 are run in on a hanger 280 with a latch 290 which engages a groove 261 which guides the latch into a slot 259. The hanger is latched to the casing head 251 by latches 281 and shear pins 273, which locate the hanger on the strings as they are lowered, are allowed to shear under the weight of the strings, which are then lowered until latch grooves 277, 278 on the strings engage latches 282 on the hanger. The handling strings 296, 297 are then removed and a Christmas tree adapter may be fitted over the upstanding ends of the tubing strings.