Drill stem mud wiping apparatus
US5012866A · kind A · utility
Inventor
Key dates
| Filing date | May 1, 1990 |
| Grant date | May 7, 1991 |
| Priority date | — |
| Expiry date | May 1, 2010 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B37/04
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A wiping tool for free fall in a drill stem is disclosed. The wiping tool is adapted to be dropped in the drill stem to wipe the inner wall. It is constructed with an elongate mandrel terminating at upper and lower subs. The upper sub supports a fishing neck and the lower sub encloses a check valve assembly. Adjustable weight means are affixed to the lower sub. Wiping is accomplished by an elongate sleeve having narrow upper and lower ends slideably mounted on the central mandrel, and the sleeve is enlarged at central portions to a diameter sufficient to wipe the wall of internal upset pipe, and wherein said sleeve is resilient, and is therefore able to reduce in diameter on passing through an internal upset and resiliently restores to the initial diameter after passing through the upset. A closed system stores incompressible fluid to keep the sleeve filled and inflated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.