Method of changing well fluid
US4893684A · kind A · utility
3Cited by
13References
2Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1989 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | Apr 5, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B37/10
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.