Page 77 - Hybrid Enhanced Oil Recovery Using Smart Waterflooding

CHAPTER 4 Hybrid Chemical EOR Using Low-Salinity and Smart Waterflood 69

1000
Unified viscosity model
Bulk shear viscosity [Delshad et al.(2008)]
Apparent viscosity [Delshad et al.(2008)]
100 Carreau model
Viscosity [cP]

10

1
0.01 0.1 1 10 100 1000 10000
–1
Shear rate [s ]
FIG. 4.2 The description of viscoelastic behavior of Flopaam 3630s as a function of shear rate. (Credit: From
Kim, D. H., Lee, S., Ahn, C. H., Huh, C., & Pope, G. A. (2010). Development of a viscoelastic property database
for EOR polymers. Paper presented at the SPE improved oil recovery Symposium, Tulsa, Oklahoma, USA,
24e28 April. https://doi.org/10.2118/129971-MS.)

adsorptions of nonionic and anionic polymers decrease permeability reduction to shut off water channeling
with an increase in the temperature. The mechanism of through high-permeable zones and water conning
temperature-dependent adsorption of nonionic poly- from the adjacent aquifers. The permeability reduction
mer is different to that of anionic polymer. For the by the polymer adsorption mainly occurs in water rela-
nonionic polymer, the adsorption is mainly attributed tive permeability rather than oil relative permeability. It
to the attraction by the hydrogen bond. Because the is known as the mechanism of the disproportionate
increasing temperature breaks up the hydrogen bond, permeability reduction (DPR). There are a number of
the attraction between nonionic polymer and rock sur- gels: movable gels, pH-sensitive polymer, BrightWater,
face becomes weak, resulting in less adsorption. For the Microball, preformed particle gel (PPG), etc.
anionic polymer, higher temperature increases the
negative charge on the rock surface. The increased elec- Low SalinityeAugmented Polymer Flood/Gel
trostatic repulsion between the polymer and rock sur- Treatment
face results in the less adsorption of anionic polymer. Experiments: polymer flood
Ayiralaetal. (2010) developed the desalination scheme
Permeability reduction for Designer Water developed by Shell. The desalination
The adsorption of polymer potentially reduces perme- scheme is designed to formulate the desired injection wa-
ability or blocks pore throat. There are a number of ter composition to suit the formation condition. Using
terms to describe the permeability reduction (Sheng, the desalination scheme, the conventional polymer
2011): (1) permeability reduction factor (R k ), which is flood can be advanced through incorporating the low-
the ratio of permeability when water flows to the salinity water as makeup brine. The advanced polymer
permeability when aqueous polymer solution flows; flood using the low-salinity water is the hybrid low
(2) residual resistance factor (R RF ), which is the ratio salinityeaugmented polymer flood (LSPF). In the LSPF
of water mobility before to after polymer flood; and process, the cost-competitive LSWF compared with the
(3) resistance factor (R F ), which is the ratio of polymer other EOR methods can bring a couple of benefits to
mobility to the water mobility during polymer flow. the expensive polymer flood. The study investigated the
The cross-linked polymers and gels exploit the benefits when the polymer flood exploits the low-