Page 79 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

Low-Salinity Water Flooding: from Novel to Mature Technology 61

• Core experiments and simulations have demonstrated that synergies
can be achieved by combining LSWF with several other IOR
techniques.
• Nanofluid treatment prior to LSWF can help control fines migration
adjacent to injection wells, and significantly maintain well injectivity.
Although nanofluid treatment has the capacity to advance the break-
through of injected water, it has minimal negative effects on the
mobility control assisted by fines migration in layered heterogeneous
reservoirs.

NOMENCLATURE

th
C mi;i Molar i ion concentration in water at initial conditions, moles/m 3
th
C mi;j Molar i ion concentration in injected water, moles/m 3
f w Fractional flow function
S w Water saturation, decimal
S wc Connate water saturation, decimal
th
Z i Valence of i ion
n N Bulk number density of ions, 6.022 3 10 25 number/m 3
κ Inverse Debye-length, m 21
k B The Boltzmann’s constant, 1.381 3 10 221 J/K
l Levers (l d for drag forces; l n for normal forces)
r FP Size of fine particles, m
ς FP ; ς NP ; ς GS Zeta potentials for fine particles, nanoparticles, and grain surfaces, mV
Relative permeability of water phase
k rw
Relative permeability of oil phase
k ro
Initial undamaged permeability
k 0
k(σ s ) Damaged formation permeability
h The surface-to-surface separation length, m
n N Bulk number density of ions, 6.022 3 10 25 number/m 3
y The ratio between the drag and electrostatic force
φ Porosity of sand pack
The percentage of internal cake thickness, about 0.10
φ c
μ Viscosity of fluid
μ w Water viscosity, Pa.s
μ o Oil viscosity, Pa.s
ε Ratio between detaching and attaching forces
F Forces (drag, lift, gravity, electrostatic)
F e Electrostatic forces, N
β Formation damage coefficient reflecting the degree of formation damage
due to pore plugging