U. S. Patent No. 5,325,918: Issued for ``Optimal joule heating
of the subsurface'' to J. G. Berryman and W. D. Daily on July 5, 1994.
ABSTRACT:
A method for simultaneously heating the subsurface and imaging the effects of
the heating.
This method combines the use of tomographic imaging (electrical resistance tomography or ERT)
to image electrical resistivity distribution underground, with joule heating by
electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density.
Measurement of the voltages and currents also permits a tomographic reconstruction of the
resisitivty distribution. Using this tomographic information, the current injection
pattern on the driving electrodes can be adjusted to change the current density
distribution and thus optimize the heating. As the heating changes conditions, the applied
current pattern can be repeatedly adjusted (based on updated resisitivity tomographs)
to affect real time control of the heating.
Pertinent publication
E-mail to
berryman@sep.stanford.edu
Lawrence Livermore National Laboratory