Apparatus for electrode heating of earth for recovery of subsurface volatiles and semi-volatiles
US5621845A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1995 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | May 18, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B41/0099
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Improved methods and apparatus are disclosed for confining ohmic heating currents to a subsurface formation in the use of in situ ohmic heating for recovery of volatile and semi-volatile materials, such as hazardous waste, hydrocarbon-like materials, and valuable minerals having thermally responsive properties. Spacing between emplaced electrodes and the number of electrodes employed are controlled to cause coupling between electrodes for more uniform and higher temperature heating. Electrode designs are disclosed which suppress spurious earth currents which would heat other formations not of interest. Suppression of electrode end currents is accomplished by the use of distinct rings of insulation, control of the applied potential along the electrode, and injection or withdrawal of fluids at distinct locations along the electrode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.