Power sources for downhole electrical heating
US5099918A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1991 |
| Grant date | Mar 31, 1992 |
| Priority date | — |
| Expiry date | Jan 25, 2011 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/06
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Electrical power sources and systems for heating in or adjacent to an oil well or other mineral well, or for heating other earth media, each comprising an A.C. heating generator that generates an A.C. heating current at a selected heating frequency substantially different from the conventional 50/60 Hz frequency used by power companies; the heating generator may comprise an A.C. to D.C. converter for developing an intermediate D.C. output of predetermined amplitude from a conventional 50/60 Hz A.C. input, and a solid state switching circuit for repetitively sampling the D.C. output of the converter at the selected heating frequency, usually in a range of 0.01 Hz (or even lower) up to about 35 Hz. A heating rate control varies the energy content and the frequency of the A.C. output to suit well requirements. Each power source or system includes output connections for connecting the output of the heating generator to a normally inaccessible main heating electrode, usually located downhole in a well, and to a return electrode; most have the capability of including a very small controllable D.C. component in the output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.