| 摘要 |
A subsea cementing system, the system comprising:
a launching mandrel positioned within a casing string;
a top plug having at least one wiper and a central bore, the top plug being releasably connected to the launching mandrel;
a bottom plug having at least one wiper and a central bore, the bottom plug being releasably connected to the top plug;
a lower dart including a central bore that is selectively closed by a rupture member, wherein the lower dart is adapted to engage and seal the central bore of the bottom plug;
an upper dart including a central bore and an inner sealing member selectively retained within the central bore of the upper dart, wherein the upper dart is adapted to engage and seal the central bore of the top plug. |
