Page 147 - Percolation Models for Transport in Porous Media With
P. 147
Chapter 8
Conductivity of a
Heterogeneous Medium
under Impulse and
Alternating Current
Even a preliminary theoretical study allows to assume, with a considerable likeli-
hood, that the use of impulse electric current has certain advantages in applications
over other types of electric action. This is due to both the diminishing of the role
of dissipative processes {in particular, heat conducting losses) and to the fact that
the concentration of energy release in an impulse can bring about the realization
of a more effective mechanism for the conductivity change in a medium at the
micro level.
8.1 Threshold Values for Electric Treatment with
Impulse Current
The majority of reservoir rocks consists of a strong skeleton and a far weaker com-
ponent, cement {clay, biotite, etc.), that conducts electricity and fills mainly the
thin capillaries. It was shown in §§1.2 and 1.3 that as the electric current passes
through a saturated porous medium, the density of energy release concentrates
sharply in thin capillaries, limiting the velocity of the fluid flow in the medium.
Such concentration is caused by heterogeneity of the medium and results in the
increase of temperature T and temperature gradients T' in these capillaries rela-
143
