GB1455051A - Casing hanger assembly and operating tools therefor - Google Patents

Abstract

1455051 Well casing hanger and seal assembly RUCKER CO 21 March 1974 [7 May 1973] 12542/74 Heading E1F A well casing hanger 17 is run into a wellhead mandrel 14, together with a sleeve 36 carrying a seal 38, a seal actuator 42 and (optionally) a bowl protector 46, and when the hanger has landed on mandrel shoulder 22 and the cementing operations have been completed the running tool 12 is rotated to fracture a shear pin 60 connecting it to the bowl protector and to partly unthread it from the hanger to expose wash ports 28, the running tool being finally released and pulled from the well after circulation of water to wash the seal and the sealing areas. At this stage, a seal setting and testing tool 62 (Fig. 3) is run into the mandrel to engage the hanger via a seal 92 and to be engaged by blowout preventer rams 68, this tool including a piston 72 which, following landing of a plug ball 94 in the tool and pressurization of the tool via its running string is depressed to abut the actuator 42 and drive it and a lock ring 40 and the sleeve 36 downwards, shearing pin 44 and aligning the lock ring with a recess 34 into which it is wedged by the actuator, the seal .38 meanwhile being expanded into contact with the hanger and the mandrel and being held in its expanded condition by the self-locking tapers on the actuator and the ring 40 and by cooperating ratchet teeth on the actuator 42 and on segments (102) which are carried by the sleeve 36 and which are biased radially inwards by rubber pads. If the hydraulic test on seal 38 shows that the seal is leaking, then the tool 62 is pulled from the well and a retrieving tool (Fig. 8, not shown) is run in to engage in the actuator 42 and contact pins carried by the actuator and engaging the toothed segments (102) so that the latter are urged out of engagement with the teeth on the actuator, allowing the latter to be raised relative to the sleeve 36 by the retrieving tool which includes spring-biased pins engageable under the head of the actuator, the initial raising of the actuator allowing release of the ring 40 from recess 34 and relaxation of the seal 38, subsequent raising of the actuator causing its head to abut the adapter 52 so that the sleeve 36, the lock ring, the actuator 42 and the bowl protector 46 can be pulled from the well to allow checking of the assembly. After such checking, the assembly may be run back into the mandrel using the tool 62 which is connected to the sleeve 36 via a shear pin and which is fitted with a spacer above piston 72 so that the seal can be reset by applying the weight of the running string to the piston. The bowl protector 46 may alternatively. be run into the mandrel separately from the hanger using a tool 144 (Fig. 9) with lugs 146 engaging in tapering openings 140 in the protector, the tool being disengaged from the protector, once the split ring 54 on the latter has engaged in mandrel recess 56. by rotating it so that the lugs 146 are urged inwards by the taper of openings 140, the lugs being held in their inward positions by a locking sleeve 148. When the tool 144 is used to retrieve the protector, the sleeve 148 is locked in its upper inoperative position by a pin (156), leaving lugs 146 free to engage in the openings 140 when the tool is run into the mandrel. An alternative form of tool for use in running and retrieving the bowl protector and for retrieving a seal assembly includes (Figs. 11 and 12) lugs 176 each of which is urged radially inwards by springs 196, 198 and radially outwards by spring 178, the latter overcoming the springs 196, 198 and extending the lugs when a piston 174 is positioned to align a larger diameter portion 184 with spring 178, depression of the piston onto ring 194 serving to align a smaller diameter portion 186 of the piston with spring 178 so that the latter is then overcome by the springs 196, 198 which then retract the lugs, the piston 174 being held in its operative positions by a detent 188 cooperable with recesses 190, 196. In a modified seal assembly (Fig. 14), the actuator 42a is acted upon by the setting tool piston 72 via a stack of belleville springs 202 surrounded by collet hooks 206 which depend from retainer 204 and engage a shoulder 208 on sleeve 36a to hold the seal in its set condition.