| 摘要 |
A non-rotating cement wiper plug has an insert, with inner and outer telescoping sleeves, within a resilient outer body. The outer body has annular fins which bear against a casing wall. The inner sleeve has a tapering nose within a tapered cavity in the outer sleeve. Slots in the outer sleeve form a plurality of segments. The inner and outer sleeves are preferably of a frangible material. When the plug is pumped down and lodges against downhole float equipment, pump pressure compresses the plug, forces the inner sleeve down within the outer sleeve, forces the segments radially outward, and fractures or separates the outer sleeve segments. The outer body is forced against the casing wall so tightly that it cannot rotate in response to the forces from a rotary drill bit. Lock surfaces on the inner and outer sleeves lock them together and maintain the outer body in its forced-outwardly position.
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