Page 20 - Hybrid Enhanced Oil Recovery Using Smart Waterflooding

12 Hybrid Enhanced Oil Recovery using Smart Waterflooding

1.5
A = 0.535

1.0
C/C 0 A = 0.563

Thiocyanate (tracer)
0.5
Magnesium
Calcium

0.0
0.6 1.0 1.4 1.8 2.2 2.6 3.0
PV

FIG. 1.13 History of effluent concentrations of Ca ,Mg , and SCN 1 of coreflooding at 130 C. (Credit:
2þ
2þ
From Zhang, P., Tweheyo, M. T., & Austad, T. (2007). Wettability alteration and improved oil recovery by
2þ
spontaneous imbibition of seawater into chalk: Impact of the potential determining ions Ca ,Mg , and
2þ
2
SO 4 . Colloids and Surfaces A: Physicochemical and Engineering Aspects, 301(1):199e208. https://doi.org/
10.1016/j.colsurfa.2006.12.058.)
70°C 100°C 130°C
60
CM-4 (SWOx4S, add Mg at 53 days)
CM-1 (SWO, add Mg at 43 days)
Oil recovery (%OOIP) 40 Add Mg 2+
CM-3 (SWOx2S, add Ca at 43 days)
CM-2 (SWOxOS, add Mg at 53 days)

2+
or Ca
20
Add Mg 2+
0
0 15 30 45 60 75 90 105 120
Time (days)

FIG. 1.14 Oil recovery of the spontaneous imbibition tests at various temperatures (70, 100, and 130 C) and
various concentrations of Ca ,Mg 2jþ , and SO 4 2 . (Credit: From Zhang, P., Tweheyo, M. T., & Austad, T.
2þ
(2007). Wettability alteration and improved oil recovery by spontaneous imbibition of seawater into chalk:
Impact of the potential determining ions Ca ,Mg , and SO42 . Colloids and Surfaces A: Physicochemical
2þ
2þ
and Engineering Aspects, 301(1):199e208. https://doi.org/10.1016/j.colsurfa.2006.12.058.)
In addition, brines with addition of Mg 2þ produce up to 60%. When the brine only has lack of Mg 2þ or
higher oil recovery with an increase in the concentration SO 4 2 , the oil recovery is less than 30%. These
2 2þ
of SO 4 . It implies the strong relationship between observations indicate that the efficiency of Mg as
Mg 2þ and SO 4 2 on the wettability modification. In wettability modifier dramatically increases when brine
the tests at 130 C, all cases increase oil recoveries and has SO 4 2 and high temperature. This study summa-

2þ
brines containing Mg 2þ and SO 4 2 result in oil recovery rized and concluded that potential of Ca ,Mg 2jþ ,