US Patent 10954740 Top plug with transitionable seal

A top latch-in plug includes a housing having a bore; and a transitionable seal, wherein: the transitionable seal seals the bore of the housing when in a first configuration, the transitionable seal unseals the bore when in a second configuration, and the transitionable seal is triggerable to transition from the first configuration to the second configuration. A casing floatation system includes a casing having a pre-load collar and a landing collar; and a lower bottom latch-in plug comprising: a catch mechanism compatible with the pre-load collar; and a landing mechanism compatible with the landing collar.