| 摘要 |
A well bore annulus wiper plug is disclosed. The wiper plug has a central body and inner and outer elastomeric ribs. The ribs are generally in the shape of truncated cones. To operate the device, it is inserted in the annular space between well casing and a drill string. Fresh drilling mud is circulated downwardly through the annular space above the wiper plug. The wiper plug scrapes both the outside of the drill pipe and the inside of the casing free of a previous well fluid.
|
