| 摘要 |
950,495. Wells &c. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. Aug. 8, 1961 [Aug. 10, 1960], No. 28665/61. Heading E1F. Apparatus for installing or retrieving, from a base positioned above a body of water, wellhead equipment in a well having a submerged casing- head comprises a pipe string supported by the base and capable of extending to the casing- head, an hydraulically actuated connector carried by the lower end of the string, outwardly extensible latches carried by the connector and engagable with the wellhead equipment, and means in the connector to operate the latches. A casing hangar 41 connected to casing 40 is engaged by the latches 70 of the connector 42 at the base and the casing is lowered by the pipe string 23 until the hanger seats in the casing-head 28. Before latching the connector to the hangar spring loaded slips 50 on the hangar are held inoperative by screws 63, but after latching the screws are removed since the slips are held by pins 64. The latches are engaged with the hangar by supplying fluid through a check valve 96 to move a cam piston 73, and immediately before lowering a needle valve 94 is opened. After the hangar has seated in the head a dart 83 is seated on a shoulder 82 in the connector, and fluid pumped down the string enters a duct 86 to force the piston upwardly. Tension applied to the string frees the latches so that the connector may be raised to the base. The removal of the connector from the hangar permits the pins to move and release the slips which become operative to prevent the hangar and casing moving upwardly relative to the head. When the connector is used to retrieve the hangar or other equipment the valve 94 is closed before lowering the connector into the equipment. A dart 105 (Fig. 8) is seated on the shoulder 82 and fluid pumped down the string passed down duct 107, through part 93, and ducts 92, 91, 90 to force the piston downwardly to engage the latches with the equipment and permit its retrieval. In a modification the valve 94 is replaced by a check valve having a spring loaded ball and a stem which locks the ball whilst the piston is forced downwardly to engage the latches with the hangar. In a further modification, useful for cementing, the valve 94 is replaced by a check valve having a spring loaded ball closing a passage leading from the space above the piston to outside of the connector, the spring being strong enough to keep the passage closed whilst the piston is forced downwardly and to withstand the cementing pressure. Specifications 948,322 and 950,496 are referred to.
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