  Fines migration behavior can either promote or obstruct fluid flow within the
reservoir and is crucial for productivity optimization that needs fundamental
understanding. The present work focuses on the contributions from effective
stress build-up due to reservoir depletion and decreases in brine salinity from
low-salinity water injection. Particle detachment is studied analytically by
using the critical retention concentration function modified with stress and
salinity dependents. Increase in formation effective stress leads to
deformations within the reservoir configurations due to micro-cracks and
reduced pore dimensions. Decreased size of the travelling channels promotes
particle detachment, while the critical retention concentration decreases. A
sensitivity study reveals that, under influence of effective stress, particle
size and fluid velocity are dominant parameters controlling the fines migration
by influencing the particle detaching forces. With decreasing brine salinity
(e.g. via low-salinity water injection), clay particles that are attached on
the pore surface increasingly swell, leading to reduction in effective pore
space and flow channel. Decreased pore space directly obstructs travelling of
suspended particles and fluids which results in permeability decline. Initial
clay particle size is found to be a critical factor controlling particle
detachment behavior. Small initial particle sizes are not likely to detach from
the pore surface as a result of weak detaching forces, hence the analysis finds
the critical retention concentration unchanged resulting in negligible
permeability decline as a function of brine salinity. Considering both effects,
effective stress and brine salinity, stress-dependent effects dominate
salinity-dependent effects at low effective stress while the two contribute
equally at high effective stress.
