Method of and system for determining the free point in a drill pipe
US7591307B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 2006 |
| Grant date | Sep 22, 2009 |
| Priority date | — |
| Expiry date | Jul 30, 2027 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/09
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of determining the stuck point in a bore hole is provided. The method employs a device, such as an inductor or coil, for writing magnetic marks into the bore hole casing. The device is incorporated into a retrieval tool so that when a decision is taken to back off from the bore hole and recover any down hole equipment, the magnetic marks can be written on the casing of the bore hole as the retrieval tool is lowered into place. As the retrieval tool is raised in the bore hole, lifting the down hole equipment towards the surface, the magnetic marks are read using a three dimensional magnetic field sensor disposed either in the fishing tool or in the down hole apparatus itself.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.