Introduction to Electrokinetics - Electrokinetics for Petroleum and Environmental Engineers - page 17

Upon application of DC current, the mobile Gouy layer migrates
toward the (negative) cathode. This motion of the water molecules and
cations within the Gouy layer drags the water molecules, cations, and
anions, in the free fluid, as well as any non-wetting fluid, along with it (Hill,
1997).
Extensive experimental work, conducted at the University of Southern
California (Anbah et al., 1964, 1965; Chilingar et al., 1968a,b, 1970, 1997)
showed up to six-fold volumetric fluid flow increases in cores containing
clay minerals, compared to only 2-fold increases in pure silica cores (see
figure 3-15). Chilingar et al. (1970) speculated that in pure silica core, fluid
flow might be, at least partly, due to a thermal effect. Mitchell (1993) main-
tained that all silicate minerals show this increased flow effect, to some
extent. Those with high cation exchange capacity (CEC) exhibit the great-
est flow increases.
EEOR is an emerging technology that could significantly improve oil
recovery, at costs below other secondary and tertiary oil recovery tech-
nologies, in environments where other technologies either do not work
or are not attractive. EEOR has a nonexistent water demand, a smaller
carbon footprint than traditional EOR technologies, such as steam injec-
tion, and does not involve injection of hazardous liquids, as is the case for
caustic and/or co-solvent flood. EEOR requires minimal surface facilities.
No steam generators, compressors, surface working fluid pumps, and/or
hazardous material storage tanks are required.
EEOR involves passing direct current (DC) electricity between cath-
odes (negative electrodes) in the producing reservoir and anodes (posi-
tive electrodes) either at the surface and/or at depth. Anbah et al. (1965)
suggested a few electrode arrangements for waterflooding operations (see
Chapter 3). Fig. 1.6 shows the originally proposed EEOR field installation
(Fig. 1.6).
The use of DC electrical power as an EEOR process was patented by
General Electric (GE) (Bell and Titus, 1973, 1974) after it had originally
been proposed by Prof. George V. Chilingar in 1950. It is currently being
developed by Electro Petroleum, Inc. (EPI) of Wayne, Pennsylvania, USA
(Bell et al., 1985; Titus et al., 1985; Wittle and Bell, 2005a, 2005b). These
two organizations, collectively, spent several years and millions of US dol-
lars in R&D to overcome encountered field operational difficulties. Their
combined efforts resulted in successful EEOR demonstrations in California
and Alberta heavy oil fields (Wittle et al., 2008 and 2011). Application of
EEOR would return about 25 dollars (2012) per each dollar invested, con-
sidering the initial installation cost and that of electricity.