Methods and apparatus for evaluating formation characteristics while drilling a borehole through earth formations
US5017778A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 6, 1989 |
| Grant date | May 21, 1991 |
| Priority date | — |
| Expiry date | Sep 6, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/01
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The MWD methods and MWD apparatus disclosed herein include methods and apparatus for rotating a directionally-responsive radiation sensor having an outwardly-directed response axis in a borehole. These MWD methods and MWD apparatus further includes methods and apparatus for obtaining a series of successive measurements representative of a geometrical parameter of the borehole as well as a characteristic of the adjacent earth formations as the sensor scans circumferentially-spaced locations on the walls of a borehole interval. Methods and apparatus are provided for determining the means of the successive measurements as well as the standard deviation of the successive measurements and then combining these computations for providing output signals that are uniquely corrected in accord with variations in the traverse cross-sectional configuration of the borehole for providing indications representative of the desired formation characteristic as well as indications respresentative of the borehole configuration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.