GB1472229A - Subsea well-head installations - Google Patents

Abstract

1472229 Subsea well completion P S PUTNAM 17 July 1974 [17 Aug 1973] 31580/74 Heading E1F A subsea drilling and completion template 10 includes a number of rings 22 with stab connector receptacles 62, 66 communicating with flowlines and hydraulic control lines carried by the template which is adapted to receive a variety of modules including, e.g. wellhead equipment modules 26-28, at least one header module 29, a separator module (not shown) a gathering header module 30, and a power equipment module 33 serving as a source of electrical and hydraulic power required for operating the other modules, each module having stab connectors receivable in the receptacles 62, 66 of the corresponding ring 22. The modules are run into engagement with the template with a diverter 100 (Fig. 2) which includes guide sleeves 124 for receiving posts 25 of the template. The flowlines carried by the template include nipples 64 in which plugs retrievable by wireline are installed prior to the corresponding module(s) being landed or retrieved. Wellhead equipment modules: Each of these includes (Fig. 2) an open-bottom housing 40 accommodating a production tree 58 and diverters 70-76 which connect with the template flowlines via stab connectors on ring 49 and which connect with the production tree via large-radius bends and with tubing sections 78, 86, 88 extending to the top of the housing where they terminate in stab connector fittings 80, 90, 92 and plug-receiving nipples 98, 99, these tubing sections also incorporating valves 82. 94, 96. The housing also accommodates a hydraulic connector 56 adapted to latch onto a well casing head 52, and may include detectors 130 which respond to the accumulation of leakage oil in the housing. The hydraulic control lines in the housing include 3-way valves (Fig. 13, not shown) which when the housing is secured to the diverter 100 connect the downstream ends of the lines to control lines which are run in with the diverter and provide for direct control of the valves, diverters &c in the housing. Once the housing has landed, the diverter is used to communicate with each template flowline in turn to allow removal by wireline of the plugs in nipples and to allow introduction by wireline of plugs into nipples 98, 99, the diverter then being released for use elsewhere. Header modules: The or each header module includes (Fig. 7) serial diverters 160 adapted to connect with an output line 140 going to a separator module, these diverters connecting via further diverters 146 with the template flowlines 131-138 coming from a number of wells served by the template, the diverters 146 also connecting with tubing sections 148 incorporating valves 154 and terminating in plug-receiving nipples and stab connector receptacles as with the wellhead equipment modules. Further valves are provided at 144 below diverters 146. The multiple diverter 100: This is the subject of Specification 1472230 and includes an upper connector 108 for attachment to a riser and a tube 114 extending between the connector 108 and a lower connector 118 on post plate 120 which is rotatable relative to fixed plate 104 by hydraulic motor 122 to allow the tube 114 to communicate selectively with tubes 110 which connect with the module tubing sections when the diverter is secured to the module. The lower connector 118 includes a nipple 214 fast with a piston 222 providing for hydraulic actuation of the nipple into and from sealing engagement with connectors 228 on the tubes 110. The hydraulic motor 122 includes a pair of piston units 192, 194 received at their ends in sliding cylinders 204 and connected intermediate their ends to pins 186 which in response to reciprocation of the piston units cause angular movement of a sleeve (178) connected via an over-running clutch (184) to a shaft fast with the port plate 120. The hydraulic motor and the connector 118 are hydraulically connected so that an operating cycle is obtained in which the nipple 214 is first withdrawn from a connector 228, the piston units 192, 194 are next advanced to rotate the plate 120 and align tube 114 with the next connector 228, and then the nipple 214 is advanced into the aligned connector and finally the piston units are reset in preparation for the next cycle.