| 摘要 |
A cementing plug (10) having a universal construction has a body member (24) and an elastomeric jacket (26) on the body member (24). The body member defines a central opening (30) therethrough with a shoulder (34) therein. To configure the plug as a bottom cementing plug, a shearable insert (48) is positioned on the shoulder, and to configure the plug as a top cementing plug, a non-shearable insert (50) is positioned on the shoulder. The inserts are interchangeable. The jacket (26) has one or more wiper cups (40, 42) which have a conical surface (44, 46) extending at an acute angle with respect to a longitudinal axis of the plug, thereby providing a substantially large contact area in use in a well casing to improve wiping efficiency and extend life.
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