Method to improve directional survey accuracy
US4956921A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 21, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Feb 21, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/022
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method is proposed for better determining the azimuth and inclination of a borehole in which a priori information regarding the magnitude of the earth's gravitational field strength, its magnetic field strength and direction are utilized to constrain the measured components of the earth's gravitational and magnetic field vectors. The constrained fit method adjusts the accelerometer and the magnetometer tri-axis measurements to optimize agreement between the measured data and the a priori magnetic and gravity field strengths and the magnetic dip angle. The adjustment that is selected is that which produces the least increase in the statistical measure .chi..sup.2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.