Method for magnetic survey calibration and estimation of uncertainty
US6179067A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1999 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | Jun 11, 2019 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/022
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The present invention provides a method for determining magnetometer errors during wellbore survey operations. It is capable of determining errors on up to three axes, with or without the use of an external reference measurement of the local magnetic field, and is capable of providing an accurate result using data from a minimum number of surveys. A model is used to correct the observed data and the corrected data are transformed from the tool coordinate system to a different coordinate system referenced to the earth. The difference between the corrected transformed data and reference data in the earth coordinate system is minimized to determine the model parameters. The present invention also provides a method for determining residual uncertainty in the measurements and for quality control of the measurements. By making the observations over a period of time, any deterioration of the sensors may be identified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.