Page 139 - Hybrid Enhanced Oil Recovery Using Smart Waterflooding

CHAPTER 6 Hybrid Thermal Recovery Using Low-Salinity and Smart Waterflood 131

1.0 1.0
Ko at 45°C
Ko at 100°C
0.8 Ko at 150°C 0.8
Oil Relative Permeability 0.6 Kw at 100°C 0.6 Water Relative Permeability
Ko at 200°C
Kw at 45°C
Kw at 150°C
Kw at 200°C
0.4
0.4
equal-perm trail line
0.2 0.2

0.0 0.0
0.28 0.37 0.46 0.55 0.64 0.73 0.82
Water Saturation(Decimal)
FIG. 6.2 Relative permeability modification due to temperature change. (Credit: Qin, Y., Wu, Y., Liu, P., Zhao,
F., & Yuan, Z. (2018). Experimental studies on effects of temperature on oil and water relative permeability in
heavy-oil reservoirs. Scientific Reports, 8(1), 12530. https://doi.org/10.1038/s41598-018-31044-x.)

HEAT LOSS the heated zone. This process modifies the displacement
The heat loss to the surrounding formations is the major efficiency of heated zone and increases the ultimate
concern in the first process of thermal recovery method. heavy oil recovery. In addition, the thermal expansion
The heat loss reduces the temperature of the hot zone of oil contributes to the recovery by oil displacement.
except in the steam condensation zone and affects the Abass and Fahmi (2013) proposed the low salinitye
thermal efficiency of the process. Therefore, the expecta- augmented hot water injection or LS-hot water injection,
tion of heat loss is of importance. Because of the heat and experimentally evaluated its heavy oil recovery from
loss, the conditions of thin reservoirs or the large well sandstone. The coreflooding experiments compare the
spacing between injector and producer are not appro- performance of LS-hot water injection to the conven-
priate for the hot fluid injection. While the hot fluid tional waterflood, hot water injection, steam injection,
flows from the surface condition to the target zones and LSWF using a BAW field sandstone core and uncon-
through the injector, significant heat loss occurs. The in- solidated sand packs. Heavy oil from the BAW field and
jection well is surrounded by the colder formations or two additional heavy oils are used. The oil from the BAW

conditions. In addition, the part of enthalpy of fluid is field has the viscosity of 1700 cp at 65 C and other

lost by either temperature decreases of hot fluid or steam oils have viscosities of 700 cp at 35 C and higher

quality reduction. In these conditions, heat transfer than 1000 cp at 60 C. The high salinity brine of
occurs by conduction, convection, and radiation. 24,000 ppm TDS and low salinity brine of 200 ppm
TDS are prepared. Three displacement experiments
with unconsolidated sand packs and one coreflooding
HOT WATER INJECTION experiment with a BAW field core are performed.
Low SalinityeAugmented Hot Water In the first displacement, a sand pack is saturated with
Injection the BAW field oil and is set to have temperature condi-

In hot fluid injection, preheated fluids are injected into tion of 65 C. The low salinity water with 200 ppm
relatively cold reservoirs. The injecting fluids are heated TDS is used for the connate water. Conventional hot wa-

at the surface or well bore using well bore heaters such ter injection and LS-hot water injection with 95 Care
as down-hole heaters. The fluids can be water, air, nat- deployed in the sand pack system. When the water-cut
ural gas, CO 2 , solvent, etc. The hot fluid injection using of displacement reaches 0.9, secondary conventional
hot water, i.e., hot water injection, is involved with the hot water injection is converted to tertiary LS-hot water
two-phase flow of oleic and aqueous phases. The front injection. Not only the reduction in water-cut, but also
of hot water loses the heat to contacting reservoir zone an increase in oil recovery is observed by switching
and the transferred heat improves the fluid mobility in from hot water injection to LS-hot water injection