Casing restriction sub
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United States of America Patent
Stats
-
Apr 21, 1992
Grant Date -
N/A
app pub date -
Apr 1, 1991
filing date -
Apr 1, 1991
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
In accordance with an illustrative embodiment of the present invention, a restriction sub apparatus for use during well cementing operations includes a tubular body having upper and lower internal recesses, a restriction ring having a shoulder engaged with the upper recess, and depending, inwardly inclined fingers at its lower end, and a back-up rubber ring mounted in the lower recess that yieldably resists expansion of the fingers as the drive plate of a displacement plug passes downward therethrough to provide a positive surface indication in the form of a pressure change that the plug is located at a particular depth.
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