Reduction of Contaminants in Soil and Water By Direct Electric Current - Electrokinetics for Petroleum and Environmental Engineers - page 84

conventional heavy oil recovery methods including steam flood or cyclic
stream flood. Also, these field pilot studies demonstrated the capability of
EEOR in cracking heavy oil in-situ, reducing water cut and increasing oil
production rates. The field tests in California demonstrated up to a ten fold
increase in the oil production from a field containing 8˚ API gravity oil.
Haroun and coworkers (Haroun et al., 2009) reported the results of
DC electric field application, concurrently with water-flood recovery
in mobilizing the connate water and the trapped oil through core-flood
studies. In the first set of experiments, DC was applied after ultimate
water-flood recovery and in the second set of experiments the DC was
applied on oil saturated core plugs concurrently with water flood from
the beginning of the test. Comparison of the two processes revealed that
application of DC concurrently with water flooding at the beginning of
the process recovered approximately 1.5-4% more oil and reduced water
requirement by 15-22% in comparison with the water flooding process
alone (Alshalabi et al., 2012; Haroun et al., 2009). However, application
of DC on a completely water swept core was found to recover 3-9 %
additional oil. Also, on repeat application of DC, up to 30% increase in
permeability of cores was reported which was attributed to clay dislodge-
ment due to electrophoresis mechanism involved in EEOR. Jihong and
coworkers (Jihong et al., 2009) reported that application of DC concur-
rently with water flooding on core samples containing oil with viscosity
of 8 MPa.s, increased the oil recovery rate by more than 5%. Also, the
apparent viscosity of the oil was found to decrease as the electric field
strength was increased.
The authors (Ghazanfari et al. 2012, 2013b) conducted a series of labo-
ratory experiments on oil-bearing rock core specimens retrieved from a
shallow oil formation in Kentucky to investigate the oil extractability and
change in the rock-core permeability under applied electric field. The
physical properties of the three core specimens (diameter: 36mm; length:
82 mm) are given in Table 2.2. The physical properties of the natural oil in
the rock cores and the brine solution used in the experiments as the sur-
rogate formation water are given in Table 2.3. Acurrent density of 1Amp/
m 2 was applied to the cores in accordance with the achievable current den-
sities of 1.0-1.5 Amp/m 2 in practical applications in the field.. The total
flow generated in each phase (oil and water) was measured periodically for
120 hours. The oil separation and analysis were conducted using standard
techniques.
As observed in Table 2.2, most of the oil recovered was produced at the
catholyte, while the oil recovered at the anolyte was negligible. The total oil
recovered was in the range of 5 to 11% by mass of the initial oil content in