Method for the detection and correction of magnetic interference in the surveying of boreholes
US4761889A · kind A · utility
37Cited by
3References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1986 |
| Grant date | Aug 9, 1988 |
| Priority date | — |
| Expiry date | Sep 10, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/022
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method is presented, for use in borehole drilling, for correcting errors in azimuth determination resulting from variations in the earth's magnetic field to which a measuring instrument is exposed. The method distinguishes between variations in the earth's magnetic field caused by the drillstring and variation caused by external sources, and the method corrects only for errors caused by the drillstring. If the error is caused by the drillstring, an azimuth correction is made based on dip angle data, thereby reducing errors caused by scale factor variations since dip angle is a ratio quantity of magnetic field components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.