Method of correcting for axial and transverse error components in magnetometer readings during wellbore survey operations
US5564193A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 23, 1995 |
| Grant date | Oct 15, 1996 |
| Priority date | — |
| Expiry date | Oct 23, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/022
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is disclosed for determining wellbore azimuth accurately, notwithstanding the corrupting influence of axial and transverse magnetic field biasing error components. A reliable value of the axial magnetic field component (B.sub.x) is determined by minimizing the vector distance between B (as measured) and its expected value B. Preferably, this is accomplished utilizing a method of radicals to solve a quadratic equation. Given a reliable B.sub.x, the transverse magnetic field components (B.sub.x and B.sub.x) can be determined from taking a number of surveys as the drillstring is rotated about. B.sub.x and B.sub.x can be determined by utilizing the assumption that the transverse magnetic field components should remain invariant as the drillstring is rotated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.