Page 137 - Hybrid Enhanced Oil Recovery Using Smart Waterflooding

CHAPTER 6

Hybrid Thermal Recovery Using

Low-Salinity and Smart Waterflood

ABSTRACT thermal recovery method is discussed in the references
This chapter discusses the applications of hybrid pro- (Burger et al., 1985; Latil, 1980).
cess by coupling low-salinity waterflood and thermal re- Thermal recovery methods modify the rock and fluid
covery methods, i.e., low salinity-augmented thermal properties and therefore, the dynamic behavior of the
recovery. The thermal recovery methods include hot wa- fluid in a porous media. The heat from the thermal re-
ter injection and steam injection. Research studies of covery methods potentially affects hydrodynamic prop-
experimental and numerical simulation have evaluated erties (liquid viscosity and relative permeability),
the performances of hot water injection and steam in- thermal and thermal dynamic properties (thermal
jection on heavy oil production by controlling water expansion, thermal capacity, thermal conductivity,
chemistry, especially salinity. The synergy of low and latent heat of vaporization), and chemical reac-
salinityeaugmented thermal recovery on heavy oil pro- tions. The effects of temperature on the hydrodynamic
duction is discussed in this chapter. properties and thermal dynamic properties are dis-
cussed. In addition, the heat loss, which is an important
factor in thermal efficiency of the first process, is also
The thermal recovery method supplies the thermal discussed.
energy to reservoirs through two processes: (1) process
in which the heat is produced at the surface and (2) pro-
cess in which the heat is created in the formation HYDRODYNAMIC PROPERTIES
(Burger, Sourieau, & Combarnous, 1985; Latil, 1980). The liquid viscosity is highly affected by the heat. The
The first process injects the heated fluids into the target viscosity decreases with an increase in temperature.
reservoirs, while the second process injects the reactants Most liquids suffer the exponential relationship
occurring during exothermic reactions in the reservoir (Seeton, 2006) between temperature and viscosity
formations. Because the first process loses the heat to rather than linear form (Fig. 6.1). The more viscous
the surrounding formations as the injecting fluid flows, the fluid, the more sensitive it is to the temperature
the performance is dependent on its thermal efficiency. change. Because higher temperature makes both slightly
Because the second process exactly releases the heat at less viscous water and much lesser viscous oil, the
the target zone where the viscous oil is to be mobilized, improved viscosity contrast favors relatively the oil
it has negligible risk of the heat loss. The first process of flow rather than water flow. This contribution by heat
thermal recovery method includes hot fluid injection, enables to deploy the exploitation of thermal recovery
hot water injection, steam injection, cyclic steam injec- method in mainly heavy oil reservoirs. In addition,
tion, and steam-assisted gravity drainage. The second the dissolution of gases such as CO 2 can reduce the vis-
process corresponds to the in-situ combustion. There cosity of liquid hydrocarbons. During the in-situ com-
are several variants of in-situ combustion such as for- bustion, a large quantity of CO 2 forms in reservoirs.
ward dry in-situ combustion and wet combustion or The CO 2 can dissolve in oil at high pressure condition
partially quenched combustion. In addition, there are and the mobility of oil improves. For the gas viscosity,
advanced technologies of thermal EOR including the kinetic theory of ideal gases explains that the dynamic
toe-to-heel air injection. Of that, the first process has viscosity of ideal gases is proportional to the square
been proposed to be candidate for the thermal EOR root of the absolute temperature and not sensitive to
process for the hybrid low salinityeaugmented thermal the pressure. However, there is some discrepancy
recovery method. Prior to the description of low between real gases and ideal gases behaviors. The real
salinityeaugmented thermal recovery method, the ben- gases viscosity tends to increase with an increase in pres-
efits of thermal recovery methods on the oil production sure. The sensitivity of viscosity to temperature is higher
are briefly summarized. Overall explanation of the in real gases than ideal gas behaviors.

Hybrid Enhanced Oil Recovery using Smart Waterflooding. https://doi.org/10.1016/B978-0-12-816776-2.00006-4
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