Apparatus for conduit free-point detection in boreholes
US4351186A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 27, 1981 |
| Grant date | Sep 28, 1982 |
| Priority date | — |
| Expiry date | Apr 27, 2001 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/09
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The apparatus includes a body member lowered within drill pipes and having an upper part (26) and a lower part (27) arranged for limited movements with respect to each other. Each part of the body member is anchored inside the drill pipes and the movements between said parts are detected when stresses are applied to the drill pipes from the surface. A first radial-coil transformer has a primary winding (35) integral with a part of the body member and a secondary winding (36,37) integral with the other part to detect the angular movements. A second axial-coil transformer has a primary winding (40) integral with a part of the body member and a secondary winding (41,42) integral with the other part to detect the longitudinal movements. The signals delivered by the transformers are linear functions of the respective movements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.