Cementeringspløk samt et pløkafskydningsværktøj til offshore olie- og gasborehuller

摘要

A subsea cementing system that inc a first wiper plug having a central bore releasably connected to a launching mandrel, and a second wiper plug having a central bore releasably connected to the first wiper plug. The system includes a flrst dart that is adapted to seal the central bore of the second wiper plug. A first increase in pressure releases the second wiper plug from the first wiper plug and a second increase in pressure breaks a burst dise of the first dart allowing cement to flow past the second wiper plug. A second wiper dart is adapted to seal the central bore of the flrst wiper plug. A third increase in pressure releases the first wiper plug from the launching mandrel. A fourth increase in pressure releases a sealing member from the second dart, which is adapted to seal the central bore of the second wiper plug.