Measuring standoff and borehole geometry
US8611183B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 2007 |
| Grant date | Dec 17, 2013 |
| Priority date | — |
| Expiry date | Sep 2, 2031 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/085
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Refracted ultrasonic waves are utilized to calculate tool standoff. An ultrasonic transmitter sends a wave toward (and into) the borehole wall at a critical incidence angle for refracted waves. The refracted wave travels along the borehole wall and continuously radiates energy back into the borehole at the critical angle. The refracted wave is detected by a receiver, and the travel time of the refracted acoustic wave from transmitter to receiver is measured and used to calculate standoff. By making repeated measurements at various azimuths (for instance, as the tool rotates), one or more caliper measurements can be made. The caliper measurements can be combined to yield two-dimensional geometry of the borehole. Measurements made at different azimuths and depths yield three-dimensional borehole geometry. Arrays of transmitter-receiver pairs can be used to obviate the need for varying azimuth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.