External pulling tool and method of operation
US5605366A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 24, 1995 |
| Grant date | Feb 25, 1997 |
| Priority date | — |
| Expiry date | Apr 24, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B31/20
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An external pulling tool for retrieving a fish from a wellbore comprises a mandrel fixedly secured to an upper sub, an outer cover fixedly secured to and depending from the upper sub, a collet assembly telescopically surrounding the bottom portion of the mandrel and a support sleeve telescopically surrounding the collet assembly and positioned between the collet assembly and the outer cover. An expandable fluid cavity is formed between a portion of the facing surfaces of the support sleeve and the mandrel. A coil spring, which is disposed between the support sleeve and the upper sub, downwardly biases the support sleeve so that it rests against a lower shoulder on the outer cover when fluid pressure is not applied to the expandable cavil. The collet assembly includes a plurality of collet fingers, each having a collet head at the end thereof. The collet fingers are naturally outwardly radially biased in the direction of the outer cover. When the support sleeve rests on the lower shoulder, the collet heads are radially inwardly displaced or wedged. Before lowering or raising the outer cover to surround the fish, the support sleeve is raised by introducing fluid pressure into the exp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.