摘要 |
A method and apparatus for multiple stage cementing of well casing in subsea wells. Also, a subsea stage cementer, plug stack assembly. The combination with a subsea stage cementer, plug stack assembly of a packing and shipping crate therefor. A trip-plug for operating a stage cementing collar to open the ports thereof. A dart adapted to enter the bore of a hollow plug to block the flow of liquid through the bore.
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